|
Post by JohnH on Apr 7, 2024 16:10:00 GMT -5
The schematic type of diagram is the only way I can think through how a circuit works electrically, unless its very simple and standard. It let's you tease out the parts independently of how they will be physically placed, to help visualise the signal flow. Plus for me, I started thinking this way as a teenage electronics nerd in the '70's, and what we learn at a young age is much easier learnt. Also, I have to start with a piece of paper and a pencil in most cases.
But then, transcribing it to a wiring diagram and adding the thinking about where each connection goes physically is an important final step before wiring it up, unless it is simple.
For many circuits, you can assemble the design out of familiar part-circuits or modules. In this case, the obvious starting point for the series-parallel switching is that each pickup would have two poles for this job, because usually that's what they do when this is done with toggle switches. Then you have another pole to switch the output, analogous to basic LP switching. So then there's 5 poles needed and we need to think harder.
The key here is that it's never required to have full series-parallel switching on both pickups at once, and it turns out that one pole can be shared. I dont think we have any hanging-from-hot issues in this one. That's an example of the enjoyable mental leap or light-bulb moment that can make these interesting or frustrating puzzles to solve. For me, it tends to happen (if at all, and much slower these days) over multiple scribbled sketches on paper.
Actually, I'm a structural engineer and I teach design. But in a tricky situation, the same process can apply to finding the solution. I'm really interested in this as an abstract topic. How do other people do this? How about younger folk who grew up and are familiar with more modern design tools than a pencil? Our guitar circuits can be a very nice self-contained toy-box for exploring how design is done in general.
|
|
|
Post by JohnH on Apr 7, 2024 6:36:46 GMT -5
hi someguyThanks for your interest in GF. It is due for an update, and I haven't done anything major to it in a few years. It does rely on quite a few excel features, mainly for buttons and sliders, but the maths of it is quite simple. Porting it to other systems isn't perfect. But the nearest version that runs on a free software is from GF6.4 where there is a link to a Libreoffice version. Google also has a spreadsheet, but I haven't tried if that might work. Meanwhile, most people who work in offices, or study at colleges etc get access to excel in some form.
|
|
|
Post by JohnH on Apr 6, 2024 21:32:18 GMT -5
Thanks Yogi, now with 50's tone control on Neck, and wiring fixed
|
|
|
Post by JohnH on Apr 6, 2024 19:21:20 GMT -5
Here's a diagram which needs a check!
|
|
|
Post by JohnH on Apr 6, 2024 16:49:11 GMT -5
I think this can be done....
Each pickup has one coil grounded as usual
One switch pole grounds whichever other coil needs to be grounded in a parallel mix.
Two poles take the hot side of each grounded coil to where they need to go, for series or parallel.
Hot side of each pickup goes to its pots
One pole switches the output from each set of VT pots
Will make a diagram...
|
|
|
Post by JohnH on Apr 6, 2024 3:22:27 GMT -5
We used to worry about such loops here on GN and GN2.
But the usual ground-loop issue between units of audio kit is related to equipment with different grounds, which have very slight voltage differences between them due to stray currents, that then get amplified. They are usually fixed by lifting one ground, or using isolatated/balanced connections.
A guitar has a single ground and there can't be a ground loop.
But the shielding does act as a cage (a Faraday cage? ) around the pickup electronics. I had a shielded cavity, and a shielded pick guard. Due to the wiring, I could have the pg connected to the amp as I assembled them together. While separated, there was a slight, normal amount of hum. But as the cavity and pg shielding touched and connected, there was a crackle, and then much quieter as the cage was completed!
|
|
|
Post by JohnH on Mar 29, 2024 14:47:55 GMT -5
Yogi's circuit is very clever and gives you the tone settings. It doesn't operate the same as the design intent though and that could be an issue for how you want to use it.
It looks to me that you'll really need to get that on-on-on to get what you seek. I had in mind that this switch would be a 3-position mini-toggle? Actually, just personally I find such switches are too annoyingly fiddly for me to use while playing (ok for presetting an option though)
But another and very viable option is that the extra switch is either another tele switch, or, a Gibson-style toggle (with care to make sure it fits, maybe an SG type). Then you can have exactly what you need with two robust guitar-optimized switches. You could probably put a Gibson toggle to replace one of the three Strat pots.
|
|
|
Post by JohnH on Mar 28, 2024 14:07:36 GMT -5
hi bpf8hz, thanks for posting. I'm going to say not, even though it's a good intent and worth discussing. The show-stopper for this use is the middle switch setting, in which with a dpdt on-off-on with 6 lugs, nothing is connected to anything. That leads to either the middle, or the 3-way output needing to be hard-wired on. It doesn't matter which order the options are placed, always there's some form of this problem in some position. The easiest (temporary?) workaround is to consider losing the middle-only option, and just use a 2-position switch either to connect the middle to the 3-way, or switch it off to just have the 3-way output. I think many players don't use M, except as part of a combo. (this message will self-destruct when Yogi shows us how to actually do this even though I've said it's Mission Impossible)
|
|
|
Post by JohnH on Mar 25, 2024 3:56:30 GMT -5
Hi mullardnerd and thanks for replying. If you can handle a few workshop skills , our design will get you a better result for less $. The Marshall forum thread has grown enormously since I posted here , so best to follow the link back there. The basic design is now M2, which has one coil. Hundreds of these have been built. With all stages engaged, it will reduce power by a factor of 1/1400. That's enough to take a 50W amp down to moderate to low TV volume. But it’s surprising how clear and reasonably loud that is. But if you need quieter, you can add more stages based on the three resistive stages and bring it down even lower. But most find it's attenuated enough. Happy to answer questions either here on on the MF.
|
|
|
Post by JohnH on Mar 17, 2024 4:05:19 GMT -5
I think you have one spare Ge transistor because a BC108 is a Silicon transistor.
It was my favourite transistor for my teenage projects in the 1970's because I had a bag of them. It was part of a series along with BC107 and BC109 (lower and higher gain respectively) and could usually be bought sorted into gain ranges A, B and C (increasing gain). The above is what I remember, those here into pedals will know more accurately.
For images, you can switch to desktop version even on your mobile. Button at lower right.
|
|
|
Post by JohnH on Mar 10, 2024 12:20:22 GMT -5
My guess would be that the metal backplate messes with the properties of the dummy coil for both its inductance and tendency to pickup up hum. Because of geometry of the coil or its placement or different winding arrangement, the dummy coil is affected differently to the coils which it combines with, plus the pickup coils are not under the plate, Hence the plate is throwing off the balance of them. The Humbucker is OK because they are two equal coils in about the same position and orientation and they are not directly below the plate.
|
|
|
Post by JohnH on Mar 6, 2024 2:44:41 GMT -5
hi themfruit, welcome to GN2 A similar arrangement to Carls 3x thread should be possible, if you'd like that simple on-off function with the silenced all-off. Can you post a photo that shows where the controls are and also shows the pickups?
|
|
|
Post by JohnH on Mar 3, 2024 19:14:14 GMT -5
Thanks Carl A wire from the ground (eg back of tone pot) to the Bridge or trem is normal, and will ground the strings by contact.
Yes the yellow rectangle at the tone pot is the tone cap. It can be whatever you prefer, its not really specific to this design but a good starting value, very common, would be 22nF = 0.022uF. It doesn't matter what style/type of cap it is (although some may have opinions!)
|
|
|
Post by JohnH on Mar 2, 2024 16:19:51 GMT -5
Hi carlbrunstril Here is a wiring diagram, which took a bit longer to get to, but it should be ok I think: I think it respects your design in terms of which control is where, and which direction the switches work. I added a treble bleed to the volume, which is optional. If you want this and are using 500k pots, then I suggest this should be 1000pF(=1nF) in parallel with 150k. Not shown: a wire to ground the bridge and strings. If somebody had a quick check of this diagram it'd be a good idea. cheers John
|
|
|
Post by JohnH on Feb 29, 2024 17:58:44 GMT -5
Yes thanks, that should do it!
|
|
|
Post by JohnH on Feb 29, 2024 15:32:01 GMT -5
hmmm well, it looks like my tone pot wiring is not as right as it should be. In fact it look wrong! (sorry!).
As drawn, the tone pot is directly connected from hot to ground, so as it gets towards zero, it's shunting the whole sound. So, remove the black wire from tone pot right lug to ground at back of switch, a put the tone cap in its place.
So connections are: volume outer hot lug to tone middle lug (as currently shown in green), tone right lug to cap, other end of cap to ground at top of switch.
Now the tone pot can't get to ground except via the cap.
|
|
|
Post by JohnH on Feb 28, 2024 7:25:11 GMT -5
Well who knew!!. Does ?? have a meaning to mathematicisns too ??
|
|
|
Post by JohnH on Feb 26, 2024 3:08:20 GMT -5
Hi maxmI don't think a simple 5 way can get that B+N tone at position 3. A superswitch can do it easily. Or, you could wire the neck pickup at position 2 and get B B+N N N+M M Or do a basic strat wiring and add a neck-on switch
|
|
|
Post by JohnH on Feb 25, 2024 15:48:00 GMT -5
I agree that some kind of temporary patch board or external switching will be good for testing before deciding on permanent wiring. That might add a bit of noise, which would be much improved in a final version.
My guess is that the best sounds will be either one rail pair, with its own coils in series or parallel. Or both pairs, overall in series or parallel and also try series or parallel within each pair.
ie out of all those, all arrangements are symmetrical with 2 or 4 coils and all are hum-cancelling. And out of them, I'm guessing that maybe three or four will be chosen for putting into a permanent switching scheme?
|
|
|
Post by JohnH on Feb 25, 2024 15:09:10 GMT -5
Hi @ahamn , welcome to GN2 and tgankyou for your ideas.
Could you explain a bit more about what issues you are solving with this arrangement? There can be reasons to consider pots of different overall values, to suit different pickups etc. But why do you want a pot that has an overall resistance that changes with different settings? From the diagram, it looks like the back half of the dual pot will take the overall value to very low values (or zero, maybe put a fixed resustor in series to it doesnt go to zero?) in the lower part of the turn?
Setting it to a lower overall value will trim some treble from the tone, but I suspect that the net result is likely to be fairly similar to what a conventional guitar tone control can do.
|
|
|
Post by JohnH on Feb 23, 2024 1:43:32 GMT -5
Hi Carl, that looks fine if its what you want . You'll need to rout a space for the volume pot. But just 3 wires will go from volume back you the main cavity. It could be a single 2-core wire with a ground shield, like a piece of microphone cable. You'll need to rout a channel for that. The main wiring can be mostly between the switches and the tone pot.
|
|
|
Post by JohnH on Feb 22, 2024 19:04:36 GMT -5
Yes that'd help. If you draw looking from the back of the pick guard as you wire it up, and approximately place the controls where you want them, indicating which direction is 'on'.
|
|
|
Post by JohnH on Feb 22, 2024 18:34:46 GMT -5
Yes that'd help. If you draw looking from the back of the pick guard as you wire it up, and approximately place the controls where you want them, indicating which direction is 'on'.
|
|
|
Post by JohnH on Feb 22, 2024 16:09:00 GMT -5
Ok great, I'll put it on the to-do list.
So questions for you: Do you prefer slide switches or mini-toggles? Would you prefer/expect 'on' for each switch to be 'up' or 'down', in terms of which way you push it?
|
|
|
Post by JohnH on Feb 22, 2024 15:09:20 GMT -5
My suggestion as I described, is based on configuring the switches as ashcatlt suggested in the previous post. The D lugs are then free for this extra job since outputs come from the A lugs. I wouldn't expect any significant pops from this because the guitar never goes fully open-circuit , even at the instant of switching. The volume pot is always there and never switched. I think this will work fine with any two-pole switch with lugs laid out 2x3. It would probably affect which way is 'on' and which is 'off'. Slide switches connect the middle lugs to the outer lugs in the direction of pushing the switch. Most toggle switches, including the mini-toggles that would probably be used for this, connect the other way. ie flick the lever up and the middle lugs connect down. But either way, the diagram would be essentially the same. You have to decide whether you prefer 'up' or 'down' to = 'on'. American and British people will disagree about this, based on our different life experiences of how other switches work. And on toggles, I had previously expected that 'flick up connects down' was always true. I think it is true of most, but I have some larger toggles built into my attenuator that work the opposite way.
|
|
|
Post by JohnH on Feb 22, 2024 7:47:23 GMT -5
Given that as ashcatlt has pointed out, you only need one half of each switch using lugs A and C, you can use the other side for a nice refinement. A feature of such on-off wiring is that there's an all-off position. Not used often but, it can create some nteresting staccato effects, or mute the guitar if needed on stage. But disconnecting all pickups can allow some noise to enter. So the optional refinement is to string all the 'off' positions of the three switches in series, so that only when all three are off, the output is shunted to ground for totally noise-free muting. If you wire the left side per Ash's suggestion, then you do another wire ground to D on 1st switch, F 1st switch to D on 2nd switch, F on 2nd switch to D on 3rd switch, and F on 3rd switch to guitar hot output. If that's interesting but not clear, can do a diagram.
|
|
|
Post by JohnH on Feb 21, 2024 17:51:10 GMT -5
No-loads are easy to make out of standard 24mm pots, but a PITA with dual-ganged or concentric ones! having a tone on each PU is all fine.
If youd like a switch to help with this, how about its wired to completely cut out the Master volume? You can find out what the tone effect is with/without the MV and if its significant or not, plus, you get a handy 'blower' switch to quickly switch up to full volume for a solo?
|
|
|
Post by JohnH on Feb 21, 2024 15:12:09 GMT -5
I think you've hit on the issues to consider. Adding an extra volume control stage does take another slight edge off the tone. Very high pot values help at max volume but add more issues as you turn down. Treble bleed helps a bit. My friend has a Gretsch, which have a similar arrangement. Here's how they are configured: www.gretschguitars.com/support/basic-control-guideIt sounded good with its Filtertrons though, and fine for what it was for. We tried a few options of how best to set it (without mods) and one thing that made a nice difference was to change from his 20' cord to a 10' one. No-load tone pots would be a great way to get high end back by reducing load. But this could be difficult to create out of dual-ganged pots. My thought is, do the Master volume if you have a particular need to suit your playing, but otherwise I'd consider ditching it, like most other guitars.
|
|
|
Post by JohnH on Feb 13, 2024 16:15:01 GMT -5
It all 'depends' on the circuit.
If you are just using one outer lug and middle wiper, to make a variable resistor, a parallel 1.2k with a 10k pot will look like (1.2 x 10) / (1.2 + 10) = 1.07k. If you are using all three lugs, then maybe 1.2k from each outer to the middle, but it'll be a bit off at mid turn (itll look like about a 2k pot). Also with any of these, the pot action is all squashed to the end of the pot turn.
|
|
|
Post by JohnH on Feb 12, 2024 23:51:55 GMT -5
Hi frets
There can be resistors in parallel either across outer lugs, or from outer to inner. It depends on the application,and its not generally possible to match the sweep and consistency of a 'native' 1k. What clever scheme have you hatched up where you might need this?
|
|