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Post by ozboomer on Nov 11, 2009 5:31:54 GMT -5
For those who came in late... My original project, the SPlender, went pretty well and the design is in daily use at the moment. There was a minor problem after construction but that was quickly resolved and gave me some encouragement to try another project - this time, I wanted to simplify the SPlender design 'coz it was a bit complicated and its operation was certainly not that easy to explain to people... and thus, the X-Blender project commenced. Now, although the design process went fairly well, I had some significant problems with the construction. What with "other priorities"(!), it took me about 3 months to build the project... only to find it didn't work . After another month of trying to debug the thing, I spat the dummy and pulled it all apart... and so, I'm now working on the next project.. This time, I simply took the pickups, pots, switches, etc from the failed X-Blender and re-assembled all the components in a more-or-less standard wiring pattern... except that: - I've incorporated an "always on" switch for the bridge and neck pickups. This is much like the common "neck always on" (in parallel) mod but I included an extra wire so that it provides the 2 missing "standard" sounds in a couple of ways; that is, neck+bridge (parallel) for positions 1 & 5 on the 5-way... and all pickups on (parallel) for the other positions on the 5-way.
- I've simplified the tone controls so that there's only a master volume and a master tone control. Much simpler and seems to be all I really need anyway (but see later).
- I've included the "treble bleed" mod, where a small capacitor and resistor are placed across a couple of lugs on the volume pot to help maintain the high frequencies in the circuit as the volume comes down (but also see later).
Now, all these changes were fairly simple to do and I actually had everything wired-up and working inside an hour. ...But! I wanted to get my series sounds back... but I'm currently lacking the confidence to fiddle with the multi-switch/multi-connection complexity after the X-Blender disaster, so I was thinking of going another route. Initially, I thought I could work on some simple tone controls to help get some beefed-up sounds. It wouldn't be a big deal to use the G&L -style of tone control.. or even do something with a Baxandall -style tone control. Having successfully built simple op amp circuits on perfboard in the past, I then thought why not do something with an active filter, for example (coming from a keyboard/synth background, I was thinking along the lines of having those Cutoff Frequency and Resonance controls)? Why not go the whole hog and build a little pre-amp with some active tone controls... and so, this where I am now. The current circuit arrangement is like this: ...where there's a sort of "black box" for the alternate tone control. I'm just finishing building a little test rig with a breadboard and some other basic components (and I'm aware of the capacitance of the breadboards but I'm looking at "ballpark" effects here)... so I'll be able to switch that into the guitar circuit fairly easily as I try some ideas out. So for now, I'm going to try building up some basic passive circuits and see what they sound like, to try and get the understanding of how these things work.. and then I'll probably have a go at a pre-amp -style of thing (JohnH: I must still get your thoughts on the comparisons/applications of your original JFET buffer, RunoffGroove's Fetzervalve design and other pre-amp designs). I was thinking it might be useful to have the pre-amp provide a bit of gain so I could get the beginnings of overdrive happening at the guitar, thus I think we'd be looking at the JFET-style of thing, given the way it distorts.. Ultimately, I'll have another go at the series wirings again... but I'll keep the "simple" idea going for now... and we'll see what sorts of sounds we can get and maybe they'll actually be all I need, eh? Looking forward to anyone/everyone's thoughts on how I might approach things... Thanks!! John
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Post by newey on Nov 11, 2009 7:06:24 GMT -5
OZ-
Adding both a "neck on" and a Bridge on" switch adds complexity (contrary to your stated goal) without adding any extra sounds.
I understand that you want to do this so that you can switch to N+B from either position 1 or 5 on the 5-way, without having to move the 5-way itself. My point is, it's a lot of redundancy for that convenience.
If being able to select N+B with one switch move is the prime consideration, consider that you can accomplish this by dedicating the 5-way switch to switching the neck and bridge only (a simple 3-way is really all that's needed), then using a separate switch to turn the mid pup on/off. That way, one flick of the pickup selector to the middle gets you N+B, and one flick of the mid switch gives you all 3 pups, or your std N+M or B+M, depending on the position of the pickup switch. And you've eliminated one switch as well as a lot of redundant options.
And, if the mid pup switch were to become a DPDT "center off" type, one could switch the mid into the mix in either series or parallel with whatever's on the pickup switch, giving you some (but not all- no N*B) of your series sounds back.
Just my 2 cents worth, anyway.
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Post by pete12345 on Nov 11, 2009 8:15:09 GMT -5
If being able to select N+B with one switch move is the prime consideration, consider that you can accomplish this by dedicating the 5-way switch to switching the neck and bridge only (a simple 3-way is really all that's needed), then using a separate switch to turn the mid pup on/off.Just my 2 cents worth, anyway. That's the arrangement I prefer, especially as I never use the middle pickup on its own. N+B is similar to M but with more tone. I also find it much easier to operate a 3-way switch than a 5-way, since there is only one middle position to find.
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Post by ozboomer on Nov 11, 2009 22:34:13 GMT -5
Granted there's some extra complexity with the 1 extra wire on the "neck on" switch... but I find it an easier thing mentally to work with a "symmetrical" switching system than to have a switch whose positions don't directly match the pickup layout, for example... and I don't really care about the redundant positions - I'm trying to go for some useful, quickly-accessible combinations; that was part of the problem with the SPlender - it was very versatile but really had too many options. Actually, Newey, your suggestion about a 3-way to control the bridge and neck pickups (replacing the 5-way), together with a single toggle to switch-in the middle pickup in series/parallel is an idea that appeals to me a lot, thank you I must see if I can nut-out the wiring for that one...
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Post by newey on Nov 11, 2009 23:03:51 GMT -5
No need to reinvent the wheel- there's a few of those schemes floating around here. I'm far from the first to come up with that! I'll see what I can dredge up . . .
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Post by JohnH on Nov 13, 2009 17:46:15 GMT -5
oz - I offered some more info on buffers and gain stages. Ive put it here: JFET buffers and buffer cablesSee the last part of the first post, edited today JOhn
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Post by ozboomer on Nov 13, 2009 18:47:36 GMT -5
oz - I offered some more info on buffers and gain stages... Ahh, good-ho... and it talks about the slight overdrive things as well.. Great! One problem, though... Where in the heck can I get those J2N5457 JFETs!? DSE (*cof*), Jaycar, Altronics (all in Melb.) all have no clue about 'em or the J201s. Will I have to ask my guitar tech to order some for me? ...or do I need to do something about ordering some from outside Oz? Thanks. John
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Post by JohnH on Nov 13, 2009 19:28:29 GMT -5
yes, electronics supply is a PITA in this country. DSE have the MPF102, which I have used for boosters and buffers. There's less gain available though. This from Jaycar should work, but I havent tried it: www.jaycar.com.au/productView.asp?ID=ZT2375&CATID=33&form=CAT&SUBCATID=475Its specs look better than MPF102 for the gain stage. I find the 2N5457 though is just right, I use them for everything. Im sure I bought a few a various DSE outlets, but I dont think they stock them officially now. Ill bet theres a few around though, but not in Sydney or Wollongong because I bought them all! A friend in the US sent me most of a packet of 100, and they worked out at 10c US each from Mouser. Heres a great one-time offer - Ill put a couple in an envelope and mail them to you if you pm me your address. cheers John
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Post by ozboomer on Nov 13, 2009 20:17:54 GMT -5
DSE have the MPF102, which I have used for boosters and buffers. There's less gain available though. Well, while I'm in 'experimenting mode', that should probably be good enough, I think... and the 5484 JFET is ringing bells from my recent explorations... Hopefully, they mightn't be too tempramental...! Oooo... Useful info.. AND! a Lagniappe all in one posting... Fantastic Would appreciate that a lot! PM to follow... Thanks... John
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Post by JohnH on Nov 13, 2009 20:50:20 GMT -5
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Post by ozboomer on Nov 15, 2009 4:54:28 GMT -5
[...about transistors... and suppliers...] Very useful thread, Fanx! ...and it seems the substitution might work... but I'll have to do some detailed study, methinks -- I can't remember all that theory about biasing, drain voltages, etc.. and the methods of setting-up the JFET so it's working properly(!) That supplier looks like it'll be useful for lots of things, including the weirdo rotary switches, custom circuit boards ( for our killer circuit designs ), etc as well as the transistors. An excellent find. More soon... John
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Post by ozboomer on Nov 15, 2009 5:13:39 GMT -5
I've now had a go at coming-up with a wiring scheme, a la newey's description (although I'd still be keen to see any designs we KNOW work, please ): The pickup combinations this arrangement gives us are: 3-Way | SW2- Off | SW2- Parallel | SW2- Series | 1 | B | B+M | B*M | 2 | B+N | B+N+M | (B+N)*M | 3 | N | N+M | N*M |
+ = Parallel * = Series ...but note this means we can't have the middle pickup alone anymore. Still, I think it's a fairly simple arrangement to use and understand for someone using the mod. Select the combination you want of Neck and Bridge pickups... and if you want to add the Middle, you can do so in parallel or in series with the (Neck/Bridge) combination. However, whilst building this up, I've had a few thoughts in terms of staging the construction. Thus, we could take a standard wiring scheme, say, on an existing loaded pickguard and then do each of the mods in turn (see the 'bracketed' sections in the above diagram), viz: - Mod 1: Simplify the tone circuit to only have a master tone and a master volume
- Mod 2: Apply the "treble bleed" mod
- Mod 3: Replace the 5-way switch with a 3-way switch and re-wire to provide B/N pup selection
- Mod 4: Include the parallel/series switching
This way, we can 'debug' on smaller sections as we build-up the entire design. It also means we'll get lots of practice changing strings and such For now, I'm still pursuing the "alternate tone" route, to see if I can come up with some little circuit that sounds useful (be it with active or passive arrangements) - this is, after all, half the fun of fiddling about with designs/module ideas, innit? ...but I really *do* like the series sounds... and I'll get my head around the wiring issues e-ven-tu-al-ly Anyway, just some more thoughts to throw into the mix... John
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Post by newey on Nov 15, 2009 11:48:03 GMT -5
Oz-
Sorry I hadn't had the chance to search the archives. But your schematic looks like it will work. And +1 for the modularity (we're big on promoting modularity lately!).
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Post by newey on Nov 15, 2009 12:27:25 GMT -5
Oz- Been rackin' my brain to think of where I last saw the "mid on" scheme around here, then had a "D'oh!" moment. It's Pete 12345's design!
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Post by sumgai on Nov 15, 2009 14:11:58 GMT -5
ob, To get a Middle only output in addition to your other choices, your upper switch would have to be a Tele 4-way. That might be more complicated than you wanted, but it's doable. Short of that, unless you add an additional switch, then you can't have Middle only, sorry to say. I do see one other potential problem here.... you've got the Middle's hot output on at all times, even when it's not selected for output (IOW, when you've selected Bridge and/or Neck only). We call this condition a "hanging hot". This is where the pickup is ungrounded, and thus acting as an antenna for unwanted noise. You can solve this by merely swapping the switch functions so that the Middle pup's negative lead is always grounded, the Bridge and Neck's shared negative connection selects either ground or the Middle's hot lead, and the Bridge/Neck selector's output terminal is always going to the Volume/Tone section. That way, no matter what pickup is currently selected for output, the other end of it is always grounded. HTH sumgai
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Post by ozboomer on Nov 19, 2009 6:36:30 GMT -5
Oooo, my first Karma point... Fanx!, newey ...and I was interested to read pete12345's notes... and that post has me thingking about individual tone controls... mmm... maybe we're getting too complex again... *shrug* Many thanks for the info, too, about the 'hanging hot', sumgai; I was sort-of wondering about that 'connected' pickup floating about in the air... I have now re-designed the circuit and although I might be forgoing simplicity for complexity a bit now I think the deconstruction/modular approach will make for an easier time debugging should things not work down the track. The Design: The latest changes: - Incoroporating sumgai's notes and changing the functions of the "parallel - n/c - series" switch. We now have one side of the middle pickup always at ground and the other end will switch between off, on (series) and on (parallel).
- Including my favourite complicator, a blend pot NOTE that the blender will ONLY work when the middle pickup is switched into the circuit in series; I don't really hear too much difference when blending the pickups in parallel mode but I *do* notice a difference when blending in series mode.
I've also drawn the diagram so you can simply scroll up'n'down in your browser rather than left'n'right -- I've gone mad on usablity issues The mods defined (again, from simplest to most complex - I think): - Mod 1: Treble bleed
- Mod 2: Re-work of the Tone and Volume controls (may be replaced, depending on my tone/preamp experiments)
- Mod 3: 3-Way functional conversion (replace 5-way with a 3-way switch, providing B, B+N and N selections)
- Mod 4: Series Switching
- Mod 5: Inclusion of a Series Blender
As an aside, although I'm still experimenting with the tone mods, I'm thinking I'll probably stick with something close to the shown tone/volume arangement or something similar. The preamp might be useful but I don't know that I'll go with a Baxandall tone control or an active filter or something... but who knows? Appreciating the useful thoughts again, folks... John
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Post by sumgai on Nov 19, 2009 12:49:57 GMT -5
ob, This looks good, but as usual, they call me "the fly in the ointment" for a good reason. Look at your series blender control.... if you turn down the control the least little bit, attempting to take out some of the Middle, you'll get more than you bargained for. What'll happen is that all the chosen pickups will be greatly reduced in volume, not just the Middle pup. This is because the N/B pickups are situated at 250KΩ above ground, and the only way they get a complete circuit (or a complete signal path, to be technical about it), is to go through the Middle pickup (a very much lower resistance). Not what you wanted, I'm sure. Try turning the Blender around such that the wiper is connected to the Series terminal of the switch, one end of the pot goes to ground, and the other end goes to the Middle pup's hot lead. That should do what you want with no problems. ;D HTH And I do like your modular approach! sumgai
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Post by ozboomer on Nov 19, 2009 16:22:10 GMT -5
Heyas, sumgai... This looks good, but as usual, they call me "the fly in the ointment" for a good reason. Paah! 'tis the idea of a forum, after all, to get as many heads thinkin' 'round things, I reckon... so no dramas about 'finding things' Ohh... Yup, I can see the whole 'series grouping' of pickups will be affected. Dang. I always have troubles with these silly blenders...! Ya, I've been re-thinking things to try and get mods done this way, so you can take a standard wiring and modify it bit-by-bit... and in that vein, only showing the 'module' where we're making changes, here's what I've understood from your latest posting: As I see it, the Middle pickup is now in a lil' section of the circuit of its own and we 'tap' some signal from it, which we shoot off to the rest of the circuit. Good-ho! I think we're getting closer now... John
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Post by sumgai on Nov 19, 2009 20:46:32 GMT -5
ozzy,
Your understanding is correct. Take it away, maestro! ;D
sumgai
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Post by ozboomer on Nov 21, 2009 1:27:15 GMT -5
With sumgai's contribution, we now have a fair bit of the design done, methinks. Again, the modular approach helps here, as we develop each section.. and then we can slot them all together Whilst all this has been going on, I've been experimenting with the Tone Control module... and I'm not getting too far here I've tried designs borrowed from G&L, a Baxandall-style thing and the standard RC-filter -style of thing... and it seems that really, the standard RC design appeals to me best at this stage. It has a single control and the variation in tone seems Ok. For simplicity's sake, I might leave well-enough alone here... and just play about with the component values some. Otherwise, I'm still thinking about incorporating a preamp module... so I'll hold-up on this design for a bit while I nut out the preamp issues... ...but so far, so good with this design, I reckon John
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Post by JohnH on Nov 21, 2009 1:33:44 GMT -5
oz - all good, but Id suggest just one addition to your blender circuit:
Really, in series mode, your blender is a volume control for the middle pup, but at mid position, all the N+B goes through it too. Its the same way i have for series pup mixing on my LP designs. So it could do with its own treble bleed circuit - ie a cap and resistor from centre to right hand lugs on the blender pot - it works for me!
John
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Post by ozboomer on Nov 21, 2009 1:40:15 GMT -5
Really, in series mode, your blender is a volume control for the middle pup, but at mid position, all the N+B goes through it too. ... ... So it could do with its own treble bleed circuit Quite right you are... Given that I recognized the 'blender module' here is running like a volume control, I shoulda remembered that it would do best with a treble bleed treatment. Dang. Still slow on these things... Fanx! for the pickup tho. John
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Post by sumgai on Nov 21, 2009 12:34:40 GMT -5
ozzy, After seeing John's Treble-Bleed comment, I re-visited both incarnations of your Blender.... I now think I was a bit hasty in my analysis, but my conclusions were correct. As I now see it, in your first iteration, if you were to turn down the Middle, the N/B pups won't maintain a constant output level, but they well never go "way" down in level, either. What I've now doped out is that the N/B pups will always be at some resistance level above ground, the exact number being an algebraic expression of VR1 and Middle pickup combined. The results can be plotted in a graph, but the simple example that's easy to imagine is like so: A potentiomenter is really a pair of resistors, each one being a variable resistance in inverse proportion to the other, such that the total is always the same. Now, if you consider the wiper at one end, the pair is the total, and that's all we have to work with. Thus, VR1 total in parallel with the approximate impedance of the Middle pup will work out to a tiny hair less than that impedance. IOW, VR1's resistance is effectively doing almost nothing to our signal. Now let's turn the wiper all the way in the other direction. Here, it's again obvious - the Middle pup is completely out of the circuit, and we have only the 250KΩ resistance to deal with. At this point, the N/B pups are not fully grounded, and they may, or may not, sound out with full clarity. I'm of the mind that since there is an additional ¼MΩ of resistance in the circuit, their output will be somewhat reduced, but it will not be completely knocked out. With me so far? Good. For the final "plot line", let's look at VR1a and VR1b, where the wiper is at "half-mast". Now we have VR1b in parallel with the Middle pup, and both of those are in series with VR1a. The calculation is really a pair of calcs, perhaps like so: VR1b x Mp / VR1b + Mp = X (two resistances in parallel) X + VR1a = R T (two resistances in series) R T of courseis the total resistance presented to the N/B pups on their ground lead. That number will go up and down, not remain a steady ratio, as the wiper is turned. (If anyone has doubts, don't just test at 25% and 75% of rotation, the varying action will occur much closer to 50%.) Overall, you might not easily notice this action, particularly on stage, but in your studio, it will be apparent. Of course, your fingers will quickly learn to avoid any spots that your ears interpret as "unwanted". Points to ponder: 1) While the blending action may not be perfectly smooth, it would probably be sufficient for most needs/uses. 2) I've purposely avoided the issue of AC versus DC. Above, I use the term 'impedance' correctly, but because impedance implies a frequency sensitivity, the fact is that my formula is only a rough approximation. If we start considering frequency, then it gets much more complicated, and the results end up with a really messy plot or graph that only an engineer could love. 3) My analysis here is much deeper than needed for most purposes! But it exercised my brain for the morning, and that's why I bother to get up outta bed at all! ;D The bottom line? You'd probably be satisfied by going with either method. In fact, with John's suggestion about the treble-bleed, "my" way may not sound as good as your first iteration. Try it both ways, and pick what works best for you. HTH sumgai
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Post by JohnH on Nov 21, 2009 14:40:10 GMT -5
I think the second blender diagram is a better way of fading the M pup up and down than the first way. If you look at the arrangement of lugs, and carry on with the analogy that this pot is like a volume pot for the middle, then the first diagram, is like 'reverse wiring', that puts the full pot resistance in series with the output when it is off. For a series circuit, that is too much for treble-bleed circuits to deal with, and the remaining N and B pups will suffer.
The second diagram has zero added resistance when the middle pup is off, and so N and B are not compromised, and also at full M all is well.
Circuit 1 puts a maximum of just under 500k in series with N and B while circuit 2 puts only about 130k in series, in a configuration that can be dealt with by treble bleed, plus, both extreme ends are not damaged.
Are you happy with the combinations that this gives? - I think they are fine, but there are ways to either fade both M and NB (that blender from my Dual sound, with a cut track), instead of just M, or have volume controls for each instead of a master volume
cheers
John
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Post by ozboomer on Nov 21, 2009 18:19:14 GMT -5
sumgai: I appreciate your detailed explanations of how the blender might work in each of the proposed configurations... but as you say, I think the blending action we're settling-on is going to be good enough for my applications; I don't need to have it working perfectly AND! I don't have to completely understand to the nth degree how it works(!) I'm just wanting something that works reeeasonably well... and to satisfy my still relatively uneducated/non-discerning ears; and from my experiences with the previous SPlender design and X-Blender discussion, I'm now going to try and keep things as simple as I can, in terms of construction (wiring-up DPDTs are bad enough for my awkward, fat fingers, thank you) and in terms of understanding how the design works. I can see and understand the 'volume control' -style of mod for the blender and I can understand the treble bleed concept... and the fact that my understanding is 'simplified' or incomplete doesn't worry me too much. In fact, I'm hoping we might be able to do something with these little sections (modules) and shoot them into the Design Modules sub-board. Simple, reasonably well-debugged modules with back-references to their discussion/parent postings would be a nice lil' contribution for me to make, I think... but only after I've built the complete design, so 'unforeseen features' can be included/removed JohnH: My SPlender mod has given me some good info on what sounds I like best at the moment. The original 'problem' of not having the M sound alone is not that big a deal as N+B sounds similar to M alone, I think. In short, I'm pretty sure I'll be happy enough with the combinations we can get from the current design. All I'm thinking about now is whether I want to include a preamp in this design... so I'll continue studying that and might try some things out... An updated layout will follow soon. Again, I appreciate all the assistance, everyone John
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Post by sumgai on Nov 21, 2009 20:03:08 GMT -5
ozzy, There's simple, there's complex, and then there's engineers! ;D So far as I'm concerned: a) so long as you aren't about to blow up gear and/or harm yourself, I don't care - I'll not say a thing in a negative or derogatory fashion; and b) so long as it's your money and not mine, I'm not gonna bust your chops. Other than that, one needn't have an engineer's level of understanding to do anything we're likely to encounter here in The NutzHouse. I threw that out there because some folks here do like to go that deeply into it. Also, in keeping it simple, we tend to forget that there are reasons for why we're not getting the expected results, and that those reasons are the ones we didn't discuss in the first place. I was merely anticipating such possibilities, that's all. I personally like the second go-round, for all the reasons mentioned by John and more, that's why I brought it up in the first place. HTH sumgai
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Post by JohnH on Nov 22, 2009 5:52:14 GMT -5
oz - I reckon, if you are considering on board boosters or buffers, just make one as a free standing unit and try it. Since they go at the end of the guitar circuit, you can test them out first outside of a guitar. There's nothing to lose, since the parts are cheap.
John
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Post by ozboomer on Nov 22, 2009 6:28:45 GMT -5
Mr sumgai, maaate: There's simple, there's complex, and then there's engineers! ;D Well, yup... After all I am one myself ( albeit civil... sometimes ) Quite true. Still, I'm just being mindful of what I understood the Design Modules sub-board to be about: something that Joe Tinkerer can look into for a "clean booster/preamp" for example and just find a circuit, have a couple of instructions for tailoring, configuring, debugging and then go to the discussion 'parent' for the gritty details if required. [...I have just self-edited and removed a long-winded blurb on writing- and learning- styles -- something for another time, that...]Ditto.. mainly 'coz it's clear, well-understood.. and for all the techy reasons, too Fanx! John
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Post by ozboomer on Nov 22, 2009 6:35:24 GMT -5
JohnH: ...considering on board boosters or buffers, just make one as a free standing unit and try it. Waaay ahead of you ...and is why the ol' breadboard has been out and in use for the tone experiments. Only drama is I'm still testing a couple of alternate tone circuits and I want to check those JFET circuits but I only have the one breadboard(!) *thinks* Also, for some reason, I find it hard to work out the stripboard layouts onto a tiny breadboard (I just think I'm out of practice).... So, I'll probably lash out and just go through the soldering route anyway for the JFET circuits. As you say, they won't break the bank... I just have to get my head 'round the way they work [...a task that's still in progress as we speak write...] John
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Post by newey on Nov 22, 2009 9:09:42 GMT -5
Your understanding is spot-on. If this works to your satisfaction, by all means post the digested version there.
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