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Post by warmstrat on Jul 5, 2007 18:12:12 GMT -5
After poking about in my guitar's guts and lamenting the price of spare parts where i live, i thought "what cool stuff couldi do to this guitar (standard squier strat), without buying ANYTHING new?" ('m about to perform an altogether more expensive and complex mod on said guitar) What I have got so far, without changing the appearance of the guitar, is to add the missing two pickup configurations (B+N, B+M+N) using one of the original tone knobs as an "override" switch to switch the bridge pickup on (and control how much of its signal arrives in the final mix), no matter what position the stock 5 way switch is in. The other tone knob has become a master tone knob, which I'm sure will be a minor change for some, but I've yet to come across a strat player who actually uses the individual tone knobs to do anything a single knob couldn't do. Here's a diagram (lovingly ripped off from JohnA's original "stock strat wiring" page on the GN site - thanks to him for the diagram. If he demands royalties, I shall have to do my own one properly ;D)  R1, R2 and R3 are whatever is already in your guitar, as is C1. NO EXTRA COMPONENTS NEEDED! R3 needs one tiny modification though - open up the pot and cut the track on the open (high side) of the track so that the wiper makes no contact whatsoever when turned all the way up. This is fairly easy to do, i am assured, just exercise some caution and test it with a multi meter before you close up the guitar. (at R3's furthest point of turning, there should be no connectivity between the wiper lug and the low side of the pot) I'm going to try this out on a consenting and curious friend's spare strat copy guitar that is currently totally unused, so i can muck about to a certain extent, but if anyone can anticipate any problems with it i'd love to know of these before I perform the mod. P.S.: This is the first mod I have designed, so a more experienced eye over it would be a great help and will be much appreciated. I will post pictures as things progress, if anyone wants. |
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Post by sumgai on Jul 6, 2007 3:05:15 GMT -5
warmie, Needs more cowbell! (That's Saturday Night Live-ish for 'back to the drawing board for you!  ) Youi've taken the Bridge + lead and inserted a resistance between it and the wiper of the master Tone pot..... why? No, not the placement of the connection, that's equivalent to connecting the + lead straight to the hot side of the volume control, and that's OK. What I'm getting on you about is the fact that merely inserting a resistance into the connecting wire won't have the desired effect. In short, without the long-winded explanation (for which I am too famous  ), let me just say that your extra resistance in the signal path will only serve to kill off some of the high frequencies, just like the volume control does when you turn it down from 10. Going directly to the point, the volume won't decrease very much over the entire range of R3, but as you increase the resistance, the tone will get more and more muddy. Bad ju-ju. How can you get around this "feature"? Well, a moment's reflection will show you that you can't use the standard volume pot configuration - when the pot's at 1, the bridge signal is killed regardless of the selector switch. Equally bad ju-ju.  Or is that really true? We want a blend pot, we just don't want it to ground out the Bridge pup when it's turned off (down to 1), for obvious reasons. That's why you cut the track in the first place. So, keeping in mind the desired cost goal (0 dollars!), let's look around a bit......... Well looky what we got here....... See that pickup selector switch? Didn't we just take one Tone pot and turn it into the Bridge "blend" pot? And how about the remaining Tone pot, isn't it now a Master Tone control? Then what do you suppose is happening with one half of the selector switch? Isn't it kinda....... empty?  Time to put your thinking cap on. Come up with a way to use that "free" half of the selector switch such that it turns off the Blend pot in the Bridge position, but leaves it operable in the other two positions. Show your changes in a newly modified diagram, don't just replace the one above, OK?  Good luck! sumgai p.s. Still and all, not a bad first shot at modding for maximum tone. ;D |
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Post by warmstrat on Jul 6, 2007 14:23:44 GMT -5
Damn. I accept what you say, and thanks for your grudging compliments... ;D I have a few queries though... "the volume won't decrease very much over the entire range of R3, but as you increase the resistance, the tone will get more and more muddy." -Surely it would operate in exactly the same fashion as my current volume knob, except only on one pickup? Or do i need to COVER the low part of the pot's track (instead of cutting it) and ground what is currently the loose end of R3? Wait... no... I'm clutching at straws here, and my brain hurts now anyway. However, ChrisK PM'd me this diagram (thank you to chris...) of what one of Hendrix's guitars was set up like...  His guitar had only a 3-way switch, and had a mid pickup blender, but his blender and mine do appear to work in the same way. Surely if it's good enough for Jimi it's good enough for you and I? "when the pot's at 1, the bridge signal is killed regardless of the selector switch." - I don't think it would be killed entirely, as the blender is in parallel, but now that i think of it, it doen't seem like such a great idea to leave it like that... hmmm let me see now... *grabs pencil and paper* |
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Post by warmstrat on Jul 6, 2007 15:26:02 GMT -5
Fixed...  My father (who has a degree in electrical engineering) confirms what i suspected, and says the blender IS shorted out by the five-way... So here it is... |
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Post by JohnH on Jul 6, 2007 15:39:57 GMT -5
warmstrat - looking at your diagram, I think it would do the job of getting you a 'bridge-on' function, without needing a switch, so it would give you access to b+n and b+m+n. So theres no harm in trying it. But I think you may find that it is not a very interesting job for a pot. Using a resistance in series with one pup to gradually suppress it in relation to other pups does work (I have tried it), but all the audible action happens in the first few k of the pot travel. So it would probably sound more like an on-off switch, rather than a control on which you can set finely judged mixes. This is because the total resistance of bridge pup plus pot quickly becomes alot higher than that of the other pups, and so the bridge sound is shunted away and fades quickly from the mix. A better pot for this job would be about 50k, with the track cut, rather than the 500k that you have.
The other comment is that with the change, the second half of the 5 way switch is now redundant, its always connecting the same points. Better to bypass it.
I think the second half of the Strat 5-way switch is an under utilised resource. You can wire p a Strat perfectly fine with standard functions without using it at all.
I also think that this subject of zero-cost mods is quite interesting, and theres more possibilities. How about using that tone knob to bring the mid pup in series with N or B at one end of its travel, and have standard parallel sounds at the other?
John
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Post by warmstrat on Jul 6, 2007 16:05:38 GMT -5
How about using that tone knob to bring the mid pup in series with N or B at one end of its travel, and have standard parallel sounds at the other? Yeah, but that can only be done if you lose the master tone as well... or i suppose you could buy a tiny cheap single pole on/off switch to do the job of the blender, like you said, it would act more like a switch in any case - but then it's not a zero-cost mod, is it? - Isn't that what i just did? Or did you post that before i posted the latest diagram? |
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Post by JohnH on Jul 6, 2007 16:42:37 GMT -5
Yes, I was writng while you posted. The series idea was an alternative thing to do, rather then an addition.
John
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Post by ChrisK on Jul 6, 2007 21:57:14 GMT -5
As I'd mentioned in my PM, the circuit as you originally had it was fine and most similar to the blend designs over the years. While you had some extra "switchage afoot" regarding one half of the 5-way in that all five positions were of equal effect (moot is), the design was indeed functional since the series blend pot was shorted out when the bridge or bridge+middle were selected, and the series resistance was between the signal bus and a generator (which is much less deleterious in effect than a resistance to ground, which will load the signal, especially at high frequencies). My father's son (who also has a degree in electrical engineering) likewise confirms what you suspected. Again, as I had mentioned, the taper of an audio tone pot is BACKWARDS from what you want for a blender (unless you're willing to turn it backwards (CCW is full on, CW is mostly OFF). As JohnH mentions, you might want a much smaller total resistance change to effect meaningful blending. The bridge pickup signal isn't shunted (as in parallel loaded or shorted), but the effective output impedance of said circuit goes much higher and the bridge signal (as are all other pickup signals) is divided by the effective series resistance and the other pot values in circuit. Pickups in parallel are essentially averaged as a function of output levels and effective output impedances to the averaging point. Again, these have existed.   These have been around for awhile a'web (file dates of 21Apr03, when I found these), electron.tailfeatherz.com/c21.htmlThey've changed some. Note that with the MegaSwitch "E" one gets a blendable version of: guitarnuts2.proboards45.com/index.cgi?board=schem&action=display&thread=1163395682Here's a link to similar stuff: alexplorer.net/guitar/mods/stratserpar.htmlSearch for "all of these words" [series parallel blender Strat pot]. Now, If'n ya wanna get reel cleever (use the first picture above), use one pot as a series blender to place the bridge or (/and to follow shortly) neck in series with the middle, try using a 500K (or 250K for now) pot for the master tone pot, connect the top volume pot lug to the wiper on the tone pot (as above), connect the cap from the bottom terminal on said pot to ground (as above), AND THEN connect the unused top tone pot lug to the bridge pickup. When the tone pot is set at "10", the bridge will be fully in circuit. If the neck position is selected on the 5-way and the series blend pot is at full series mode, you get (B+N)*M. As the tone pot is rotated toward "0", the parallel blended pickup is quickly removed from the circuit and then the tone control works normally (why the 500K is suggested). To limit the lowest output level of the blended-in pickup, the top terminal and wiper terminal of the tone pot can have a fixed resistor in parallel to limit the maximum resistance in series with the blended pickup. A reeeely cleeever sort would use that there other half of the 5-way switch to select which pickup would be parallel tone blended in. Uh, you know, when the bridge is selected, the neck is a blended.........(Opposite IS.) There's more than enough cognition afoot here than to require an actual picture thereof (after all, at least a kiloWord (kW) has been rendered a'theme). (This sort of means that I want YOU to draw it up.) And, uh, like experiment or sumpthin'. |
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Post by warmstrat on Jul 7, 2007 3:18:36 GMT -5
the taper of an audio tone pot is BACKWARDS from what you want for a blender (unless you're willing to turn it backwards (CCW is full on, CW is mostly OFF). You'll note that in my diagram, the low end of the pot is on the opposite side as the volume and tone pots. Learning how to use a new switch system is gonna be weird anyway - the direction of the pot won't make it much worse i don't think. Now, If'n ya wanna get reel cleever (use the first picture above), use one pot as a series blender to place the bridge or (/and to follow shortly) neck in series with the middle, try using a 500K (or 250K for now) pot for the master tone pot, connect the top volume pot lug to the wiper on the tone pot (as above), connect the cap from the bottom terminal on said pot to ground (as above), AND THEN connect the unused top tone pot lug to the bridge pickup. (This sort of means that I want YOU to draw it up.)  That was easy ;D... I swear i'm missing something here... I'll work on using the other side of the switch, but this should do it for me for now... |
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Post by warmstrat on Jul 7, 2007 14:24:25 GMT -5
Hah! Its done! I did it to a strat copy (actually a yukky modern squier) as per the diagram above, but left off the tone pot, so one pot is a series blend, and the other is a parallel blender. Despite the irritating hum when you let go of the strings, it really sounds great, and has turned from a totally unused "spare guitar" into something really respectable that could actually be used. Just for fun, we added a reverse phase switch to the neck pickup for some extra sounds, making it even more fun. At the last count, we had 13 different-sounding combinations. Not bad for a few cent's worth of wire and solder and an hour or two's careful work!
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Post by JohnH on Jul 7, 2007 14:58:13 GMT -5
Cool! - you are now a GNut-case! Have a +1 from me.
I was looking at that diagram, and you'll see how the ground sides of the neck and bridge are connected and controlled by the series blend pot. When its in series, the unused N or B is hanging at one end, ie, its connected at one end to the circuit but not grounded. This could contribute a small part of the noise. What I'm getting to is that a good job for the other switch half would be to provide switching to the ground sides of N and B, so they are only connected when they need to be.
John
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Post by warmstrat on Jul 8, 2007 6:09:50 GMT -5
a good job for the other switch half would be to provide switching to the ground sides of N and B, so they are only connected when they need to be. Hmmm... Like how? *thinks* *fetches paper and pencil* p.s. thanks for the point! btw how do the rankings on this place work? (new member, full member, god etc) |
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Post by JohnH on Jul 8, 2007 6:47:36 GMT -5
The rankings are all based on quantity rather than quality. I think Full member is at 100 posts, Senior member at 300, God at 500, and at 2557 you can be UnklMickey.
John
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Post by warmstrat on Jul 8, 2007 7:21:44 GMT -5
aha. nice. btw the squier that i modded - it DIDN'T have ground loops!!! I was astounded, to say the least...
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Post by sumgai on Jul 8, 2007 14:04:02 GMT -5
The rankings are all based on quantity rather than quality. I think Full member is at 100 posts, Senior member at 300, God at 500, and at 2557 you can be UnklMickey.
John Oh no you don't! I'm not letting two of them in here, no way Jose! ;D 50 - Junior 100 - Full 250 - Senior 500 - God The authors of the Forum software have not given any thought to those ranks being based on Karma in addition to quantity, which saddens me, we have so many deserving contributors here. sumgai |
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Post by ChrisK on Jul 8, 2007 23:14:42 GMT -5
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Post by warmstrat on Jul 9, 2007 14:35:55 GMT -5
the ground sides of the neck and bridge are connected and controlled by the series blend pot. When its in series, the unused N or B is hanging at one end, ie, its connected at one end to the circuit but not grounded. This could contribute a small part of the noise. |
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Post by ChrisK on Jul 10, 2007 17:03:48 GMT -5
The clue was that it was stated that touching the strings seems to reduce the hum. Don't ever let go!
Is the bridge/string ground connected to the bridge and neck pickup ground (and hence "floated" by the series pot)?
As in ground loops (redundant ground paths) are bad and it fortunately didn't have any of them,
OR
ground loops (connections to grounds and pot shells) are good and it didn't have all of them?
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Post by UnklMickey on Jul 11, 2007 1:49:46 GMT -5
The rankings are all based on quantity rather than quality. I think Full member is at 100 posts, Senior member at 300, God at 500, and at 2557 you can be UnklMickey.
John ;D 50 - Junior 100 - Full 250 - Senior 500 - God The authors of the Forum software have not given any thought to those ranks being based on Karma in addition to quantity, which saddens me, we have so many deserving contributors here. sumgai Pffft! As if there could be another. Sure, there might be another madman who furiously posts away until his postcount is astronomical. But he'll have his own demons to deal with, and his own brand of insanity. Disclaimer:There is, and will always be, only one UnklMickey. Accept no substitutes. |
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Post by sumgai on Jul 11, 2007 3:32:29 GMT -5
Unk,
You had me at "Pfffft"! ;D
sumgai
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Post by warmstrat on Jul 11, 2007 8:08:58 GMT -5
ha ha ha ha ha. I will pwn you all! Is the bridge/string ground connected to the bridge and neck pickup ground (and hence "floated" by the series pot)? Um... if i understand you correctly it isn't. All the grounds are electrically connected, but when the series blender is active, as JohnH and my diagram confirm, there is no grounding for the other unused pickup. As in ground loops (redundant ground paths) are bad and it fortunately didn't have any of them Yes. I was amazed because of the guitar's hum levels before modding. I was expecting them. |
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Post by sumgai on Jul 11, 2007 13:16:13 GMT -5
warmy, As it happens, ground loops are potential sources of audible hum/buzz, but they aren't guaranteed to produce such. Note that part about "audible"....... As you found, lots of other things are usually the culprit, we just have to hunt them down and eradicate them, one by one. So far, you seem to be ahead of the game, and that's a good thing. ;D sumgai |
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), let me just say that your extra resistance in the signal path will only serve to kill off some of the high frequencies, just like the volume control does when you turn it down from 10. Going directly to the point, the volume won't decrease very much over the entire range of R3, but as you increase the resistance, the tone will get more and more muddy. Bad ju-ju. 
