Piezo/Mag combination questions...jazz box project

[4real]

Nov 16, 2011 5:11:53 GMT -5 JohnH said:

As a further option for the blender, I could imagine a dual-gang blender with a switch for mono/stereo, and one more buffer module required. Ouputs 1, 2 and 3 are replaced by just two outputs. In mono mode, both of these are the same and get the blended mix, in stereo mode, mag goes to one and piezo the other, and the blend knob now acts like a balance control to fade one up and the other down. But I can’t see a good way to do this that lets you have the full signal level of each into separate outputs when needed, so I have not drawn such.

cheers
john

ps, sad to hear that one of our pollies couldnt take his Fender bass to work at Parliament House today for his weekly jam session, for fear of getting his long thin instrument case exploded by the CIA
www.skynews.com.au/politics/article.aspx?id=685780&vId=

No Bass...oh well, it's only 2 days...I didn't even know they had a parliamentarian Jam session...

...

I'm finding it a little hard to come to terms with the idea that one can't have a fader between outputs...is this not what is in a common stereo?

Perhaps one needs a dual gang volume control reversing for one as the blender...but then perhaps in the centre both would be on 'half volume'...but then how does one make such a control in a stereo speaker system?

Perhaps I will just have to be content with the Hex thing being separate if I want to have master control on the blend or separate P/M outputs. There might even be a performance advantage to being able to do this though not as much as complete control over the volume of the instrument I suspect.

I expect that passive mode to be an 'emergency thing' and that one of these gangs could be switched in to accommodate this for passive mode...perhaps combine it with a power off switch (another aspect that may need to be addressed)

I do think that I will want to be able to have separate out's for each signal, especially for recording situations...but perhaps I have to hear it and through different systems.

My thoughts are that I may well wish to run a stereo system with mag on one side and hex and piezo on the other but with the hex separately processed then recombined...potentially into 3 channels of a PA or recording mixer/interface.

Perhaps to achieve broader aims like this will require an outside box or 'pedal board' that includes the hex power thing.

We do seem to be looking at a few switches...perhaps too many to practically hide if not careful...hiding switches may get tricky given the difficulty getting into the the guitar.

I feel like I should be able to work out at least in some block form what I am wanting to do here so a little frustrating and given the length of time to get parts and all...it would be nice to have a plan...but perhaps it is something that needs to be worked out through some experimentation...I seem to have a lot of parts coming to do just about anything twice over!

[ashcatlt]

guitarnuts2.proboards.com/index.cgi?board=reference&action=display&thread=3195

Perhaps one needs a dual gang volume control reversing for one as the blender...but then perhaps in the centre both would be on 'half volume'...but then how does one make such a control in a stereo speaker system?

 
Does your stereo get twice as loud when you set the balance control to the center?  Most don't.  See Blend and Pan Pots.

I'm not completely convinced that you'll want your guitar to get twice as loud when the blend control is centered, either, but that's for you to decide.  

If you end up with a "True Blend" pot you'll probably want some "mixing" resistance in series with each source at some point.  Otherwise, in the middle position where both are full on you'll have the two buffer outputs connected by straight wire.  Usually not a good idea.  Maybe use your choice of Blend or Pan pot basically wired as individual volumes on the buffered mag and piezo, then to JohnH's full blend circuit with a trim pot.  The individual outs will come from before the trimpot and will crossfade as you desire.  The trimpot will act like those mixing resistors I mentioned, but allows you to adjust the "centered blend" in a set-and-forget manner.

And how bout that stepped Master V?

[4real]

Sorry Ash, mind is distracted by a few things of late...not taking everything in but did see your posts...

The stepped vol, I am assuming something like a ten position rotary switch with graduated resistors and as many gangs as required...something like that?

Of course possible, but complex and large and well...it would click between positions so not that desirable compared to simpler options offered and a conventional control

...


Good point about the blend thing. I was trying to think my away around john's comment...

I can’t see a good way to do this that lets you have the full signal level of each into separate outputs when needed, so I have not drawn such.

The last drawing is close to the desired result and with extras, the previous scheme too has it's appeal. It is close and in the end some experimentation will be required.

In truth, other than recently testing out and hearing the piezo system (which worked very well) I have really not heard this guitar other than acoustically which is not really a gauge of anything on the electronics side.

What it seems to be required, thanks for that link which I will consider further...is a blend pot for mono and a pan pot function when used with separate outs. As things will all be active, it is unlikely to suffer from the added load to make this happen I suspect.

You are right, one does not want the guitar to be twice as loud in that mode. John is also right to point out that the piezo system has it's own volume control and that allows for quite a bit of 'mix' and his last scheme does provide separate outs and in a round about way some control over the major systems while maintaining the basic stripped down control layout of three knobs (and hidden switches for various 'modes' of operation).

The description of your blend/pan thing seems to make a lot of sense and worth pursuing and elaborating on I suspect.

Perhaps incorporating this idea into John's scheme above will prove a good solution...will study that link more and await further comment!

...

Some more parts have come in, but still lacking some of the newer variations such as the dual gang volume knobs needed to really start work...those and a plan of course! Amongst them a couple of linear dual gang pots.

The critical parts for working on the hex at all and making that anything like close to a reality are still lost in the mysteries of the red china mail service (doh) but generally things get here eventually. A bit surprised as I sprung for an extra postage charge, but go figure.

I'm kind of parting up for a range of experiments it seems, most suppliers having a minimum order amount or quantity so as things change or I need to access another supplier or another part...well, the costs are mounting and the plans not set and some things not even fully proven...but such are the ways of things.

My general approach and possibly the best way is to try out a few of these ideas and amalgamate things into something that works. Likely, built to a scale format of the guitar in cardboard, possibly built onto an aluminium plate that can be inserted right into the guitar once built and tested and hold all the switches pots and circuits it their correct place. A bit of work but would allow for better shielding and future tinkering and easier to get in and out of the guitar.

...

I appreciate all the thought and interest everyone is putting into this project, I hope that it will be a credit when finished to the ingenuity of the collective.

In reality it is a 'concept guitar' with a lot of 'bells and whistles' that are likely to be rarely used in practice I suspect. By enlarge I can forsee, putting the player hat on, that I will want to simply plug the guitar in and get a blended mag/piezo signal out of it with a simple single lead and amp set up. Similarly, I generally play in standard tuning and without effects. So, the capabilities are all bonus points but interesting enough.

Perhaps the most 'rewarding' capability that has come from the overall project is that it is a go anywhere, compact acoustic instrument that plays with the comfort of an electric and is matched to my style and technique. It is a fun guitar to play that invites playing it physically. It is of cheap construction but sufficient quality to work well. It has some aesthetic appeal.

Along the way I am making small improvements all the time, improving intonation and getting a handle on the trilogy system and what is required to keep that happy. I can for instance successfully drop from E to Eb in an instant and things like drop D or even open G are fairly reliably obtained. This project is at least if not more about the physical instrument as the electronics to run it.

However, in essence, for any kind of performance other than practice, and the true sound is very much locked in the electronics. Any extended range and texture locked in the success of the 'hex' side of things which is something of an unknown still.

If one were to do it again or produce a less 'concept' one off swiss army knife of a guitar, I suspect I would be simplifying things down a whole lot further perhaps...but that is not likely to happen any time soon, so all the eggs are going in this one basket!

Anyway, all suggestions and comments are food for thought and influencing the end result in one way or another and I suspect from the results so far, something truely unique will come of it...perhaps by christmas.




^ a pre-improved pic to remind people what we are working on...

[JohnH]

I'm still suffering from an inability to find a good way to do the mono blender/stereo balance pot - and I've thought about those dual gang blenders and true blenders etc.

On a home hifi, the balance pot doesn't need to change roles, and if it has a loss of signal due to the way it works, that is accounted for in the gain of the overall circuit.

There could be extra gain stages added, or switchable gain, with more circuit complexity etc...yawn!!

But the basic circuit is very close to doing what you need, with just the simple very high quality buffer modules and simple pots.

Here's another doodle. Since as you describe, the hex may be unlikely to need mixing into the other pups at the guitar, I got rid of that switch (but its still possible), and put in the idea of a switched jack socket on the piezo as you noted.



So in mono mode, you have the blend of whatever mix you want, switchable to passive mag. Plug into the direct piezo out and the piezo is removed from the blend. Now you have what was the blend control, acting as a mag volume control, and you can turn it all the way to max for full mag.

So you have full control for balancing the two sounds in stereo, using the piezos own volume, and the blend knob which is now acting as a mag volume. And all under master volume control too.

I think that separate pots for piezo and mag, when in stereo mode, may be better than a balance pot, because they are very different sounds and going into different amp systems. eg, you could dial in the right crunch on the guitar amp, without messing up the piezo sound going into a PA system. Also, if you need to turn up the mag to get full output, you don't want to also be turning down the piezo!

cheers
John

[4real]

Thanks john for all your efforts.

It is not likely that I will have 'crunch' in this style, the intention is to kind of getting a stereo 'two guitar' effect. The problem with distortion is that it is hard to play any chords, let alone the complex 'clusters' that are becoming more a more of a by product of the contrapuntal melodic ideas.

The real purpose of the 'hex' thing is to provide a following octave 'bass' (or sub bass like effect) mostly. I can see other uses of it to provide colour though. Part of the difficulty, though also it's charm, is that one needs to arrange within a narrow range and only the colours available from a single guitar (generally an acoustic style).

As a result, the hex thing needs to be processed and will always require a separate output really....unless the processing was done on board, but not something I'd want to power and all that...better off on the floor or amp.

Generally though, the guitar will not be used with the hex, but it may well be the case when one wants to have a big stereo mix with acoustic sounds with it's own amp and mag pup in another, perhaps with a warmer tome or the treble rolled off for a jazzier like sound.

In general use, most likely a blend...so priority of controls should probably follow that format.

...

We are well on the way though to a workable if not great solution.

...Meanwhile, got to spend the afternoon playing through some material and developing the technique. It is kind of a funny experience and only really works when you can relax and just let it flow...then it is a bit like Vai once noted, enjoying watching yourself as a kind of 'out of body' experience..but then he can be a bit OTT at times.

I also have a terrible problem remembering things with a lot of detail, much more at home when things kind of flow naturally...so although based on arrangements and such, there is a fair degree of 'improvisation' involved. The main thing is that you can navigate the melody, have a strong bass line and the backbeat as required...and having as many ways to navigate through a tune as one can so you don't get lost. A lot of practice tends to let you forget eventually and just trust things will flow through to the end of a tune LOL.

Another interesting aspect is that at least 50% of the time I don't get to play familiar chord shapes (though I keep them in mind), you have to just keep you 'ear' out for the individual lines framed by the melody and bass.

...

Anyway, the ideas are coming along and I am sure by the time we get parts here, something will become apparent.

So in mono mode, you have the blend of whatever mix you want, switchable to passive mag. Plug into the direct piezo out and the piezo is removed from the blend. Now you have what was the blend control, acting as a mag volume control, and you can turn it all the way to max for full mag.

So you have full control for balancing the two sounds in stereo, using the piezos own volume, and the blend knob which is now acting as a mag volume. And all under master volume control too.

I think that separate pots for piezo and mag, when in stereo mode, may be better than a balance pot, because they are very different sounds and going into different amp systems. eg, you could dial in the right crunch on the guitar amp, without messing up the piezo sound going into a PA system. Also, if you need to turn up the mag to get full output, you don't want to also be turning down the piezo!

NOt quiet sure about this, but more in line with some of my thoughts.

Passive/active mag
Blend
Piezo out with separate mag when used
separate hex

I really don't want to add more controls and operating multiply volume controls, especially when one is tiny and on the edge of the guitar to effect the changes needed is possibly a bit impractical.

Ash pointed to some ideas that may bring better results, what we are looking for is a blend say on one gang and a pan for use when separate outputs are used...either controlled by the master volume.

Imagine for instance, you are playing a tune with a more piezo sound for the verses and then you want to bring up the mag and lower the piezo...without stopping the flow of the playing. Or perhaps dialling in a Wes Montgomery sound that you only want to use for a solo section against the 'hex bass' then back to am more balanced acoustic sound for the rest of the tune.

Most of this is to create a big range of variety in tones from the one guitar and easy to operate while doing it.

The 'concept' for this guitar is to address some of the things that I think the solo guitar genre and instruments lack. Range and separation (hence the hex ideas) along with a consistency of colour (hence the Hex and different pickup systems) and; A tendency to rely on 'guitar keys' generally the sharp keys (hence the multi-tuning which I seem to at least have allowed a half step flat tuning reliably so far)

Will have to study the scenario a little more in the morning perhaps...

[JohnH]

One more time...!

This explores how blending in mono might be combined with a proper balance control in stereo.



Diagram A is the type of blender circuit we have been discussing. Diagram B is the same pot, converted into a balance control between two output channels. The key is the 100k resistors. With that value, the output from each channel at the mid point 3db less than that of the single output in diagram A. So with two channels pumping, the overall power is the same – seems good. When the balance control is fully turned one way, one channel is cut out, and the other rises until it is about 1.5db below full signal, which is quite a small drop. So this balance control would give a credible knob to tweak two separate channels up and down without mixing them. The blend version is giving a full range of blends, and the volume output of both circuits is reasonably similar.

The two circuits can be combined. Diagram C shows a dual gang blend/balance pot (2x 500k lin), you have an output for the blend and one each for the two separate channels, plus the dual gang master volume as before. Five buffers needed. A passive out can be added too.

Diagram D, instead of having both A and B in parallel, it has a 4-pole switch to convert A into B (call it a mono/stereo switch), so only a single blend/balance pot is needed and four buffers. This one also has the passive switch shown. There’s another feature too, being the switch on the piezo socket, which allows three modes of operation.

If the 4-pole switch is in mono mode, and only the upper output socket is used (labelled mag), its the mono blend of mag and piezo. If a cable is plugged into the lower output, we get yesterdays diagram where piezo is removed from th emag output and there are effectively two separate mono channels, one for mag controlled by the 500k blend pot (but just acting as a volume control for mag) plus the master vol. The piezo has its own volume control, plus master as before.

Flick the 4-pole to ‘stereo’ and you have diagram B, with a balance control plus master volume.

4PDT toggles are about $7 at Jaycar – I have some spares if you want one though.

That about it..best I can think of!
cheers
John

[4real]

Thanks John, again much appreciated and at an after midnight glance, seems to do the tricks required...will have to study it a bit more.

Thanks for the offer on the 4pdt, I ahve quite a few of thoes about from the sustainers...

What I don't have nor coming are 500k linear pots...grrr...I'm not sure that I have even seen them about...is only the blend/balance linear, a 100K linear case too much bleed (I have two of them, doh)...

Will do a quick search in the morning perhaps, I am accumulating a few too many excessive parts I fear, and costing...so I may well be wanting to off load some onto you guys sometime soon...

Now...500/470k linear dual gangs...1 or 2 required (or is the vol log?)...and the switch jack looks like it need only be a stereo jack..that's cool...check for 100k resistors while I am at it...

4 buffers, should some have a power saving resistor mod?

Busy for the weekend but have most of the parts now to start building except for these pesky new pot/pots...I'll likely need a power on switch by the look of it too...so that will be a few switches in the thing wont it with these and the HB S/P and 'tone switch' If I do that...better not get them confused in operation LOL

Much appreciated John .. pete

[JohnH]

There are a few options, and I think some refinements possible. The circuits above could do with a bit more consistency in levels and mix between the mono and stereo modes. 100k pots could be a part of that, combined with a slightly different output stage with a small amount of gain.

Just a few questions:

Out of those circuits above, which of C or D appeals most?
What pots do you have or have ordered, values. lin/log and single/dual ?
Do you have any other transistors - eg some small NPN transistors of any type? (thinking of a low gain JFET stage with a transistor buffer out - watch this space.)

How about a two stage approach to the build, which might allow initial testing to inform the final version? Build a couple of buffers and a blender module and hook those up with the dual gang master volume, no complex switching. Direct outs if you wish. You should have enough to do that and it will let you evaluate the mixing and output levels. The modules will be useful for the finished version and a simpler first stage build will help with troubleshooting. (ie guaranteed: It wont work first time!). A simpler build will get you playing quicker.

John

[4real]

Thanks John...

I never assume things will work first time or be quite right, no matter how good a plan! Especially with something as unknown as this.

The plan is to take the pickup wires out fo the guitar, extended as necessary, power from the piezo preamp out and work to a template and test as much as possible with the guitar in a playable condition but with wires sprouting out of it to tinker with...so we are right there.

Did a search and a 500K or similar dual gang is hard if not impossible to get. Mouser never got back to me, but $40 in post is crazy, so something wrong there.

So...I am likely to have enough parts t make 25 of these things, due to minimum orders and the like from suppliers like element14. Most have come in to make the buffers. Each time I order is another ten dollars so things are adding up.

So, plenty of transistors a of the type specified (forget the number) and any number of bits and pieces about in boxes. Not used to working with discretes nor remember the numbers...but there are a few.

The pots though, have two 470k log's that you linked to coming apparently. Have several 100k dual pots. A range of single pots about. I found one dual gang, likely audio, 250K pot. There is a possibility that I could take this and other pots apart and mix and match as I ahd to do with the sustainer pot to get a push pull of that value and on those uber pots too...but it is tricky and does not always work. Potentially one could make pots though of mixed value though..perhaps a dual gang 250K will work fine as is.

So...yes, a more cohesive plan would help, but some experimentation is needed.

I quite like the last plan for the blend/balance thing...more of the functionality that I envisaged perhaps, but seems a bit fussy.

I believe I have a two stage discrete 'prechamp' kit about...

www.ozitronics.com/docs/k100.pdf

rather thn reinvent the wheel, these things might be bent to such a circuit if you wanted gain over buffers or give ideas.

I have this nagging thought that there is an easier way..but then i am naive perhaps.

One could imagine say a stereo out socket with piezo/mag but when a stereo plug used going to separate outs, a mono plug a blend thing...but i ahve not yet read crissk's article I am afraid...so underestimate the requirements

...

You are right though, I think some actual work needs to be done...so, run the wires out of the guitar, the piezo is tested, now do the same for the HB in passive mode. Wire a S/P switch and perhaps a switch selected tone control...ok. Now, run it through a buffer perhaps. Build a basic blend with a 100k pot as described perhaps and see how the combination works. Perhaps test the passive bypass switch. Test out some of these ideas for a blend/balance control with the 100k or 250k pots available maybe...

Keep working at it till it is close to being right...play the thing in different combinations and assess the importance and effectiveness of what I 'think' I desire or want verses the reality of things.

Work out how one can physically accommodate all these 'hidden' switches with a difficult guitar to access (thinking of aluminium plates held on by the pots and shaped to put the switches in the right position and come out of the guitar when the pot removed.

...


Yes, so a good plan, the dual gang volumes not yet arrived...


The GF is on her way so a lot of this stuff is packed away...but grabbing a bag of stuff...I ahve a couple of single gang 500K Lin, 100k log, 100k lin, 3x 500k log, 10k log, 2x 100k dual gang lin...and two 470k dual gang log on the way. Possibly one 250k(suspect log) dual gang about.

Any number of switches of various types and hundreds of mixed parts, some hard to identify LOL.

With a min order of $10 and the time it takes to get some parts and some things like resistors and such coming in 10,25 or even 50 minimum numbers...it all adds up and collecting a few excess parts along the way as one can imagine. Still, if that is what it takes...and there are still other things to make I am sure along these lines.

The whole hex thing may well need some of these parts over time to experiment with for all I know...but perhaps time to limit costs and make something work and experiment.


...

Ok, better run...hope that answers some questions there...the transistors are 2n5457 n polarity JFETS

cheers... pete

[4real]

I may be over complicating things of course...

On a side note, I imagine that most people realize that just about everything that GFS offers is hyped up marketing of Artec stuff. What artec has though is far more extensive and in the idea of acoustic/mag/mic and other such things, they have quite a range...



www.artecsound.com/acou/edge.htm

They quite legitimately off this 'warning...
www.artecsound.com/pickups/electronics/images/counterfeit-warning.gif

on their preamp circuits...

www.artecsound.com/pickups/index.html

which of course look all too familiar...

...

It's hard at this stage to really ascertain what a good compromise is on this project, clearly it is an electric guitar and the electronics are a key component, any of the schemes offered has some appeal and it is probably a lot to ask for the thing to do 'everything'...especially without hearing the options.

The intentions are good but there are limitations I guess and clearly a good danger of over engineering things to become less practical than more simple solutions.

The piezo test really surprised me with a huge range of sounds out of the EQ on this guitar and the bridge ideas worked exceptionally well to bring out the best in that...the tuner is not chromatic and a little 'so-so but it was cheap (about $50) and likely cheaper and better than other DIY solutions if you have the room and all that.

Given the range of control there, and the unknown of the HB thing and what the combination sounds are, perhaps asking too much to separate the signals, but there are sound reasons why one would like to do that. We have found solutions to that too, but the control may be a sticking point.

How the third hex system will also integrate or even work is a huge unknown.

So, fully intend to do some exploratory experimentation and even to install one of the compromise schemes and return later to refine things perhaps as new ideas emerge...hmm...

Again thanks to the brains trust and john especially, it was inevitable that the construction side of things would give way to the electronics and wiring side of things eventually LOL...

[Billw100]

Pete, Have you tried the artec pre amp at all?

I just ordered up that very one. I am working on a hidden mag pick up guitar (2 single coils) with piezo. I got that artec so I could blend the two pickups types.

I was stumped on if I should try the 3 input (mic, piezo, mag) setup, but will go with the 2 input for now since it has a lower profile to put in an electric guitar body once I strip it down.

[4real]

No...I've not, but be interested in how you ordered, costs and all that from artec as they tend to be a manufacturer wholesaler.

I have a number of these kinds of things, might have to off load a bunch of stuff in the future in fact...I was not aware of these new artec preamps and other very cool gear that they offer and some simply rebranded and over priced and hyped by GFS..hmmm...

It would likely be a better solution than some of the options I am exploring, in some ways at least.

Artec make (like eden in necks and such) most of this sort of stuff and manufacture for major companies like components. They are typically low to mid range products but seem to work well enough.

In this guitar, I actually wanted to address some of the problems that I have experienced with electro-acoustic piezo guitars...in particular handling noise and thump and other areas of performance. This is mainly involved in the way the bridge is designed to take the energy mainly from the individual strings and very little comes from the 'top'.

In the testing I have done, it seems to have been successful with little sound coming from say 'tapping' on the body other than on the bridge saddles themselves. I will often damp the strings or rest the edge of my right hand on the bridge itself just beyond the strings and I did not want to get any noise from using such techniques. The bridge even seems immune from what I feared would be noise with the multi-tuning system...people with tremolo/piezo guitars often complain about this kind of noise that makes that combination virtually unusable.

...

I'm still waiting for those dual gang volume pots but am tinkering with the guitar and playing it a fair bit, finding a few problems that very much need to be addressed.

By making the mods to brace the top, the guitar top is 'lifted' and resists the deformation by the string tension...ok, good...however of course, all the intonation was done without and that is enough to throw things out. With this guitar, I took care i the bridge design and setting of it to ensure good intonation and I need that for the music it is designed for...hmmm.

So, intonation is off and it is not an easy 'fix' though doable and anticipated. I can unscrew the bridge and move it slightly, fill and re-screw, to get pretty good I am sure...but to adjust finer I need to actually file of each aluminium saddle piece. In this guitar, and by necessity, the intonation is not adjustable like an electric. Still, it is better than a typical arch or flat top acoustic with a straight angled saddle...but not 'good enough' for me LOL.

I am even thinking of doing some kind of compensated nut, so holding off on these kinds of things to think and decide.

Plus, I am enjoying playing the guitar and putting a bit of time in there and that informs the design too. In fact, that reminds me I was going to write about the tune "Life On Mars' and the many examples and variations of the minIV chord effect in that 'where is my mind' thread on that subject...an astonishing tune in many ways.

...

Followers of this thread will also know that one of the really novel and innovative features is the hex system...as components for that have finally arrived and it is a bit of work, I have begun that in earnest the last few days and should be able to show progress later today to give people a far better idea of what this mysterious thing might actually be...with any luck the guitar and the hex will catch up with one another!

...

I just ordered up that very one. I am working on a hidden mag pick up guitar (2 single coils) with piezo. I got that artec so I could blend the two pickups types.

I was stumped on if I should try the 3 input (mic, piezo, mag) setup, but will go with the 2 input for now since it has a lower profile to put in an electric guitar body once I strip it down.

Because i don't want body noise or feedback and the guitar is not remarkable acoustically, mics are completely out of the question for me...how good does the raw sound of the guitar make, if not great, then why mic it?

If running as a piezo system, there is no imperative for it to be hollow or have any chambers and the like either. There has been quite a few great piezo/electric hybrids here of late and well worth tracking down the threads. There is a hidden piezo/mag 'stealth strat' that looks great and practical, JohnH has long since had a hybrid strat + piezo and lot of circuit options, Treguiers mag/piezo acoutic cited in the designs here is also very good.

There are a number of reasons why I am doing a full body 'true' acoustic, a large one is that while an electric solid body can be amde to have 'acoustic' like qualities, it still has the electric's attack, decay, sustain and harmonic signature of that style of guitar. Nothing wrong with that, but for my purposes, I am after those more acoustic qualities that better suit the music to be played on it. I want the playability of the electric in the neck, the acoustic in the bridge and a more hybrid moderate sustain, quick attack and acoustic or semi acoustic jazz like qualities.

I also wanted a certain kind of set up, with an extreme neck angle and high bridge above the top. There would be no way to 'hide' magnetic pickups in it, nor would I want to really. You need to be relatively close to the strings to get a decent response from mags generally that is not possible with this kind of guitar. One only need look to some of the 'failures' that Leo Fender tried in such 'stealth' things or the reactions of people to things like the variax 'no pickup' look IMHO...on many guitars such strategies are really ust a 'novelty' and may even hinder better performance.

This guitar, though has many novel features and aesthetic qualities, like most of my projects, is trying to stay somewhat true to functionality and purpose of design and informed by the music and techniques I use and this facilitates. Hopefully things are not just novelty for novelties sake and will enhance the playing of the thing.

In my opinion, and it is a minority view I suspect, there are far too many things that we guitarists seek or covert that were cleaver in their day but could be done better now...far too much mojo. Almost everything is hyped and refers back to 60 ears ago or more and the original guitars. Pickups in particular 'sound like' the old XYZ and go through fads (like P-90s and PAF's and all that) but very rarely do we get hype about anything genuinely new or people enthused about such things as they are about 'retro cool'.

This may seem odd on a thread for a guitar that would appear to be so retro it pre-dates the solid body, but there is a deeper philosophy at work here if you will and there is a purpose to these things and an attempt to make things that are functionally as good as I can make it...without it looking like some dali-esque post modern sculpture.

This is the opposite of the post-modern philosophy that inspires 'hidden pickups' and the like and harks back to perhaps the more 'victorian era' where they celebrated the working os a steam train or the girders in the Eiffel tower and the like....but with modern functionality, picking up the better ideas that have come along, like Leo's straight string pull headstock design, or the cool tone and superior playability of a traditional jazz guitar. Most of my projects have a bit of this, something old, something new, something completely new and unique of my own creation and all mixed in with a familiar aesthetic but still 'forward thinking'...as if it was meant to be.

I'm not sure what others think, I think I achieved this well with my tele, and in this project, perhaps more so...it is not finished yet of course, but I think the completely novel use of a fender head on this traditional body shape works really well and seems to be 'natural' and not out of place. Functionally, with the mulit-tuning things especially, it is far superior than a more traditional 3+3 headstock on a gibson...again, it is function that rules over 'tradition' not just a 'novelty factor' or that I could only get a fender neck (which is not the case btw).


Anywa, gald of any interest of course, there may well be little features on this and others guitars here that can inform other projects and is the great things abut GN2...

[Billw100]

on the artec home page there is a list of vendors. www.artecsound.com/contact/index.html
Looks like 4 in Oz... if they are still in biz. I am having trouble with those links.

I have only 1 here in the US called
www.acousticpreamp.com/servlet/the-31/Edge-BT-MG/Detail So I ordered from them.

My guitar is a teisco that I was given to me with a neck and body only. Kind of looks like a jazzmaster. It has a giant route on most of the top, so I will make a new top out of wood, which will push the pickups closer to the strings, and might have issues with clearance. if nothing works out, then pickups go in as normal. Maybe a tele neck pickup, or lipstick would look nice. Maybe even a wood like acoustic hole mag pickup.

I have never really cared for the jazzmaster like pickguards + metal parts with switches, so I want something that is all wood, and clean. Something that works like a taylor T5.

[4real]

Sounds cool, there are much smaller piezo amps about, I ahve a few and wondering if I should have chosen a fender branded 'baggs' brand...i had not realised the onboard tuner in mine is not chromatic...hmmm

I have my own strong opinions, and are really just that, so everything is good...I just have my own kind of design criteria to try and keep things on track and functional yet have a certain 'something'...not sure if I achieve it...

...

Now...news of the day...



more on the 'hex thread' otherwise...9.17mmx60mmx5mm... a new kind of pickup is born...

[4real]

THe last, perhaps, cmponents turned up today...apparently the only thing they could didn't just post as instructed..instead they couriered two pots in a truck to the middle of nowhere on a 32C day...post free...amazing...

But a few things happening about here in recent times and been away. Some new projects in the wings perhaps...but hope to make some decisions and try out a few of these ideas for this soon and perhaps work out a good way to fit everything inside.

...

The hex thing was a partial success, but not enough unfortunately. It makes a good sound which is something, but lacks in the separation. I hope to play with the magnets on the prototype that may help...but I have a plan D (i think that is where we are up to) which might be exciting and possibly smaller, but will have to see how things pan out...

...

Now, given that there will be a few switches, i will need to work out how to secret them inside...I was thinking of a bent aluminium plate to hold the switches and held to the guitar by the pot, wired up and perhaps even shielded to it...seems like a plan...

In the immediate term though, need to wire everything up externally to be sure it works.

I am leaning a little towards the blend/pan option at the moment, but will attempt to take it one step at a time perhaps...

[JohnH]

Hi Pete

If you would like to dip a cautious toe into the realm of these modules, might I suggest that you have a go at a blender module with a 500k linear pot. You can see how it works, ground one end and you have a volume module you can try on the mag pup. Or, try blending from piezo to mag (even mag with no buffer). Then maybe a simple buffer module to add to the mag. Step by step, building up a feel for what these systems will behave and sound like. and creating parts that will be useful whatever you choose.

John

[4real]

Yes, very sound advice John....one step at a time I think with this thing.

I think a cardboard duplicate of the output hatch to prevent excessive drilling into the real thing. Get a power line from the piezo peramp.

Then, wire the HB with a series/parallel switch for a lighter sound and perhaps a tone switch for a darker sound on it...these being performance tools attached to a plate held on to the volume pot. Build a preamp module for this and perhaps a temporary 'passive' switch to assess things there.

Combine the piezo signal with the mag and see how things 'blend' using the piezo's on-board volume control. Perhaps mount things hanging out of the f-hole and mounted on some cardboard so the guitar is reasonably playable and spend a little time playing it and assess the sounds and what I really want it to do in that light.

Build a blender module and see how that goes and again, assess this function and sound...

Then, looking through the various proposals, try a separate out into two amps and see how that fares, how useful is the 'stereo' effect. I actually think that it will be a superior sound to have the piezo through another amp or as a recording tool...

If this is something that is of use in 'performance' mode, then try and arrange some kind of blend/pan arrangement and switch to make this happen perhaps as proposed.

Possibly I will need a on/off power switch...maybe combine it into the 'passive mode' switch so I can leave the guitar plugged in (as I have a tendency to do)...switches like that and the stereo switch I don't really see as performance tools and could be mounted in a similar way to the others from the pan pot.

The hex side of things is still a great unknown. I'd still really like that to happen and predict it will, I have a few strategies on the pickup design tried to get better separation and a completely different approach that I have had for a while and have been doing a little research on that looks very interesting.

If and when that works, that can be combined in later and determine how important that needs to be combined into the settled scheme of things.

So yes, sage advice...it may not take that long to get a decent working basic scheme, install it all and live with the guitar in that mode for a bit and see where there might be some 'deficiencies' or strengths. The piezo has been tested to work and produce a good sound but it will be interesting to hear the whole guitar as an electric instrument for the first time.

...

There are still lots of little 'niggles' in the guitar set up that need attending, having an electric output may well assist in that side of things. For instance, when I re-braced the top there, it was a very good idea and significantly helped with the tuning system and added a lot of strength into the guitar without that much loss of acoustic volume...likely something of a feedback inhibitor too. But, by lifting the top top against the string pressure, the intonation is now slightly off and will need adjusting.

I am still considering some kind of 'shelf nut' compensated thing as this style of play uses a lot of open strings and open position fretting as a rule and that is where you get the most problems...this too would require intonation adjustments and this can only really be done by moving the bridge a bit (it needs to be screwed in place though) and likely filing the bridge saddles back a touch.

There are also a few cosmetic things as well, truss rod cover and the like, perhaps to stiffen the head against flex...I don't think there is much but every bit helps with the trilogy thing.

...

So far with the tuning system, I'm still a little wary of these GFS locking tuners, could have been a mistake there...hmmm. Otherwise, I am using half steps down on each string. It works pretty well to drop the whole guitar down to Eb and very well for simple things like dropped d and again reasonably to things like open G. Dropping the whole guitar down to D is a little less reliable and the strings a little loose, though and interesting sound...I might have to be content to do a bit of tweaking when retuning with the device but it is certainly quicker than manual tuning. The ideal I guess is to be able to use the thing in some ways like 'adrian legg' and his banjo pegged ovation...



He uses very light strings, so not sure how he is able to keep things stable so well like that...not really thinking of using the trilogy in quite that way, but it is cool that he is able to change key like that in the middle, or play the solo entirely with the tuning pegs LOL.

...

I have found the ability to lower the guitar to Eb to be a good thing though. The looser strings have a different sound and you are able to get out of all those guitar-y sharp keys for a bit of variety. The looser strings also aids in some bending tricks within chords, such as simulating the opening of a tune like 'wicked game'...

(E)........Bm..........................A..........................E..............
------|--------------------------|---------------------|--(0)-----------------
--0---|---6b7--------------7---|---------5p0--------|--(0)------------0---
------|----7-------------7------|------6-------6------|----------2--s--1----
------|----0----------0---------|----7------------7s-|---2--2s4---4s2-------
------|----x----0---------------|------------------0--|------------------------
------|----7------7-7--------0-|--5----0-5----------|---0-------------------

hmm, perhaps not the best ASCII notation, but that Bm chord means bending up a half step while holding the other notes and an open note by pushing it towards the floor and the high e string right off the fretboard with the first finger alone. Obviously a touch easier with looser strings and allows other such bends and vibrato things that gives it a bit more of a slinky feel. There is a back beat damped strum on 2 and 4 as well. I will often do a bit of a solo section too as besides the B bass note, you have the open A and E strings to support it and the looser strings allow for some country like double stop and oblique bends which seems to suit the song. This guitar also allows you to pull on the strings behind the bridge to create 'b-bender' like tricks within chords, such as bending the G# (1st fret, G string) to A within the E chord. There are a lot of things one can do with harmonics too in this classic but simple tune and this guitar and lowering the tuning a little gives a lot of options...either for this 'finger picking' solo guitar thing, on in more conventional playing techniques...so gets bonus points!

It's very hard to notate this 'style' at the best of times. The idea is to get a distinct bass line, not just root notes but more movement than shown typically, and dampened, the open notes to ring against the others, lots of expressive slides

A big storm today, lots of thunder, lightning and rain (still 16C at 7:30am though)...so if I get some other things done, will have a go at a few things perhaps...

[4real]

Not sure how much time I will have to play with things till next week, have to 'clean up'..well, doing a spring clean anyway that's overdue...and the GF wants me for a few days...

But, let's start with the HB...



I think I ahve some on/on/on dpdt around...so might try this control for the HB, (D) will give series parallel and a split on one switch.

As there is no real tone control, I was thinking a 'tone switch'...any suggestions as to what to use?

Basically the idea of this is to give the option of a 'dark' jazz like sound. I have some 10k and 1K trim pots about I think if that helps, a few different cap values. The tone thing might also be good with the piezo combination that could be set 'bright' and make an interesting mix.

These switches will be hidden just inside the F-hole below the volume control and thinking of making an aluminium plate held on by the pot to mount them, probably along with the HB buffer module.

...

The blend control is likely to have 'non-performance' switches mounted in a similar way on the other side and end of the f-hole. Things like the 'active/passive switch' (possibly including a power on switch in that function to save battery) and the stereo/blend option if that works out.

...

I've not given up on the hex thing but could take some time. In fact I am listening to Pat Metheny's "what's it all about" at the moment and love the amazing sound he gets out of his novelty stringing (the middle strings are an octave higher and the whole guitar tuned low) and is what inspired this idea. That deep bass sound is so rich!

I am awaiting parts and am likely to try another strategy and the idea may evolve a little as well.

I think the guitar looks better with the third black knob on it though, so intend to mount something as a dummy while I work on that aspect...it just seems to balance the look a bit more for some reasons, ties in the trilogy a bit more.

If the hex thing 'ever' works out (never say never) there are lots of things that might work out well for this extra knob...but I am still pretty hopeful for it eventually and some of the new ideas look pretty good.

...

Having the guitar playable as an electric for the first time will be a treat though it will likely take a bit of fiddling about to get it right...

And, there are still a few things to do 'mechanically' to get the best out of I am sure...every little thing makes a difference and they are adding up and pose some interesting ideas perhaps for a future incarnation somewhere down the track perhaps...hmmm

[4real]

Ah, lot's of reasons and excuses for not getting around to wiring this up...

But, got a little time today to do a bit of prep work...

I made 4 of John's 'buffer/blender modules'...








A heap of switches and such about, no on/on/on so no split. Worked out a template for the switch holding plate so have to make that, it is held on by the volume pot and another on the other side with the blender. I will be able to attach these tiny circuits to this assembly and fit them after testing.

The first one will have a series parallel switch and a "dark' switch for the mag and the master volume control. The Other will have the stereo blender to pan switch and the passive switch power on/off switch...well, that's the intention.

So, once the plates are made, will wire up the HB and give it a test, work out how to get power out of the piezo system and try the HB through it's buffer perhaps. Try the piezo and mag's perhaps direct into the volume control and see how that works out, the blender perhaps, the pan idea...I imagine just play around with some options, then work out how to switch things and only then start drilling into the guitar and installing things into it.

...

Having a few too many projects at once and general life events and the season has gotten in the way a touch. It will be good to get this out of the way and work on improving the playability with the electronics more settled.

It will also allow me to work perhaps on the divided pickup a little more, I think a whole new approach is needed there, so awaiting more parts. The original prototype was damaged beyond repair in an attempt to replace the magnets, a nice try and worked as a pickup but not adequate separation which is the point. I think this new alternate approach might be better so will explore that.

I am also messing around with sustainers again, perhaps a new 'model on the way' though not for any particular guitar and certainly not this one....but there has been a bit of interest so I may make some of the kind of thing on my tele available in very limited numbers and select people that could handle the wiring necessary to install such things.

[4real]

Had a few chores to do, mowing the grass and all...so slowly does it but got a few things done...



I ran a wire for power directly from the piezo pre-amp out the back of the guitar and also took a mono 1/8" jack instead of the stereo one to defeat the power output switch wired to it, running a shielded cable out the back along with the mag pickup wires...



Here I am wiring a series/parallel switch to the HB and after that I wired another switch with a small cap to ground and then a output jack for testing.

So, got to hear the mag sound in this guitar. A basic HB neck pickup sound, very quiet (expect so with an HB with all that shielded wire) and warm though not 'powerful' as befitting a PAF style gibson. I think it will benefit from the buffer on it.

The S/P switch gives too flavours, the parallel a little quieter and 'lighter' in sound. The 'tone' or "dark" switch gives that classic 'muffled jazz' tone as per wes montgomery...woman tone in EC vocab I guess. This is good for this kind of thing, but hoping for some interesting sounds with this kind of thing combined with the piezo perhaps.

The buffers are made, so the next step is to test some kind of scheme where I can hear the HB through the buffer and try a few basic ideas with the blend as well...so get to heare the combined sound.

If all's well there, I may attempt the more adventurous blend/pan option for a true stereo output...perhaps running it through to amps and assessing the worth there as well as any problems such as ground loops between amps and the like.

I will also need a power on switch that I am hoping might be combined with the passive option...but one step at a time is perhaps best there...

...

The wildlife have learned that I am a bit of a soft touch and ever more varied creatures are getting bolder...like this Ibis that came a knocking...



Weird creatures, very ungainly/ugly on the ground, but majestic fliers...

[gumbo]

Weird creatures, very ungainly/ugly on the ground, but majestic fliers...



...hmmm..

...known a few people like that....

[4real]

AHHHGGGHHH!!!

This is got to be the hardest thing to wire, so many frustrations....grrr

Still, at this point, I have the S/P switch, "dark" switch and finally, got the piezo out. Have not tried a blender yet, but wired them both to the output and experimented with 'mixes' with the piezo volume control and a volume on the mag.

I also tried a passive active switch and incorporated a power on to the preamps...not sure this is the best idea as ther is a fair pop...though it is not a performance tool

Hard to say what is going on though...the volume control is alomst an on off switch, so not good. And in this mode works as a master volume it seems on everything though not intended the way I wired it...hmmm...not sure if putting the buffer after the pot was such a good idea.

I can confirm that the buffered mag is a great clear sound though but there is some odd interactions going on and not entirely happy with the way things are going and must say it has been frustrating. I'm not even sure that the power is actually going "off" as the original piezo had a strange kind of ground switching jack. I have permanently wired the ground and switch together and switched the +ve to the other circuits in the passive mode, but I am not sure that was the best idea either.

This is of course what happens when you don't have a clear plan, preferably verified.

It is making a sound and a decent one at that. There is a bit of hiss, more so from the buffer it seems. You get a full range of piezo EQ's when the mag is in passive for some reason, less so and overwhelmed when the buffer is in play...very odd too...perhaps I need a buffer on the piezo as well

...

The volume control is a disappointment, but it was the only 470K double gang pot I could get. Could I use a 100K with the buffer ahead of it and forget about the passive thing perhaps?

Anyway, any thoughts would help...perhaps a basic plan and then take it from there. It might well be that I will settle for a simple blend perhaps, but there is certainly something odd going on with the interactions of things...

[JohnH]

OK, well you are making progress.

The pops are understandable when you switch power to an active circuit. If you want rid of them, a cap and a resistor on the power, and maybe a high value one on the output will fix it. Ill sketch if you wish

Shouldnt go combining two active citcuits directly, they fight each other and both lose. The blender module keeps them seperate'd from each other and combiones their signals. For a first pass at that, you can try just the pot part of the blender, ie left and right lugs to the piezo out and the mag buffer, output from the wiper.

But lets first review the mag buffer on its own. Is it noisy? it shouldnt be with those circuits - maybe a detectable amount of hiss but very small indeed. Check voltgae at the source (transitor side of the output cap), it should be 5 to 6 V. Also, give a good hard strum and check for any distortion.

cheers

John

[4real]

Thanks John

The noise is a faint hiss really, all the cabling is shielded but hanging out the back of the guitar, so not idea...acceptable.

Fighting each other, well that seems to be the case. Oddly, in passive mode combined the piezo is quite dominant and the reverse is true when the buffer is on the mag.

I have single gang 500K log and linear, but not happy at all with the action of the volume control. I got some 100K dual Lin...could they be used as a volume control if the buffer comes ahead of it for the mag? So, thought 100K lin for the blender which I think was the original. Those 500K's are not available. I do have single gang though.

I'm leaning towards a simpler scheme unless something really interesting comes out of the blend, the sounds seem to be in there but as you say, fighting each other.

I'm impressed with how the buffer helped the Mag though, lots of highs and clarity...might put one in my strat and other guitars...

Anyway, might have to strip things right back again and try a few different bits and pieces to get the potential out of it. Might ditch the passive thing and rely on good soldering and carry a spare battery. I just realized that the piezo pre-amp also has a 'lo-bat' indicator so should not be caught out really. I thought of putting a 100uF cap on the switch perhaps, a resistor too?

Will try some alternate pots and the blender with the 100K dual gang and see how that fares tomorrow perhaps...

[JohnH]

A 500k volume pot on the mag, before the buffer, should work fine. Log or Lin to taste. The buffer needs to not have a volume pot between it and the blender however, or else the blend wont go all the way to mag.

You should be able to get a result with mag, 500k pot, buffer, then 100k linear blend pot to mix in the piezo, with output from the wiper.

If you want to de-thump a power switching circuit, put the cap from + to - on the board you are switching, then feed the + power through a series resitor, calculated to drop about 1/4V based on the current draw, then switch that. The cap then acts like a storage battery for a second or two, slow to charge up and slow to run down and the circuit does not feel any sudden voltage changes. My overdrive box in the effects schematics section works this way.

John

[4real]

Any suggestion for the typical resistor for a 9 volt preamp?

The pots are a big problem in dual gangs and most unsatisfied with the results for the type I got, linear is out of the question.

Perhaps I should run the mag through a buffer and then the blender and then the volume and out...these things have got me confused, more these dual gang post and combining different active systems...hmmm

While I am getting a sound out of it, just sitting around plucking the thing and getting used to the electric sound of the thing after playing it acoustically for so long. Lots of bass and the acoustic sound is good, the mag gives it a fuller body but I think there is more that can be got from it.

Lots of thunder and lightning this evening with the sun going down, all very dramatic...strange days lately...here's a view from the W/E

[JohnH]

Perhaps I should run the mag through a buffer and then the blender and then the volume and out...

good idea

But what is happening with the volume pot, why are the dual gangs not good?

th ede-thumping series resitor depends on teh current, but you could try a 100Ohm or maybe a bit more, with your 100uF cap. Only important if switching power while live.

[4real]

Yes, quite right, it is only important then and not likely (though the passive/piezo mix is qutie a good sound and the only time the piezo is getting the full effect when 'mixed' in this crude way. Not likely to be used that way, but slightly concerned that the power might never be 'off' given that the piezo output jack switch is defeated...

I got the dual gang 470K log as linked from element14. Don't know what happened there, unlike everything else would you believe, they actually couriered two of them out here, when they could not find the place, they run for directions then attempted again...could not believe it...still freight is free...hmmm

Anyway,there is no linear equivalent and searched about but found nothing like them...at an outside chance, I could attempt to 'make something' but always a delicate business.

So, dual gang Log, but seems to only work from 8-10 both with and without the buffer (with piezo not connected or with)...Ideally I want a smooth overall travel and off in the "0" position.

I have a few lin and log 500K single gang about.

I have heard that a lot of active electronic systems use 100K pots or even 25K...like EMG's so perhaps it is worth a try.

It's a tricky operation though I have made some progress. The buffers work and the hiss is very slight really compared to the improved signal from the active system. The HB wired fine with the S/P and 'dark switch' (though considering a small trim pot to tailor it a little more).

Just something haywire with the combination...in the passive mode the piezo is strong and huge range of EQ'ed sounds, but with the buffered HB much less so...but then, perhaps a blender will help to balance things out...

Frustrating I must say...

[JohnH]

Just something haywire with the combination...in the passive mode the piezo is strong and huge range of EQ'ed sounds, but with the buffered HB much less so...but then, perhaps a blender will help to balance things out...

Its the battle of the buffers! The one with the lower output impedance wins and both can get distorted. Gotta get that blend pot between them, then you will have smooth blends.

With the 470k pots, is the problem that the volume drops too fast when you turn down? Id try a linear 500k on the mag. Another idea is to add about a 220k resistor from hot outer lug to centre lug, as in a treble bleed circuit but no cap. That will reduce the volume fall off.

[ashcatlt]

Static resistors can be subbed for a blend pot if you want. One in series with each buffer out and then their junction to the output. Basically you need some resistance between the two buffers, so they have more load than just each other.

Tapering resistors are a good idea. Can make a linear pot act log or antilog, or make a log pot more linear. They do divide down the total resistance, though, which isn't a big deal after these active circuits.