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Super bright mod, ... replacing a guitar?


bluefoxicy

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Hey all.

 

I've got my special II sounding pretty okay and I think maybe after the new graphite nut it'll sound really great. I'm also thinking of doing three more mods to it once I get my new iron (which hopefully can actually melt solder):

 

[*] Replace the pots with DiMarzio 500k push-pull pots (stock pots do SUCK, tone=2=10)

[*] Push-pull the Tone pot to coil tap the lower pick-up for a brighter sound (it's bright NOW!)

[*] Push-pull the Volume pot to activate Telecasting Mode: single coil tap the neck pickup (brighter, weaker than the bridge pickup a la overwound bridge pickups in a Telecaster) and activate a Volume pot bypass (.022uF cap and 300k resistor?) to let through the highs (a la the Telecaster volume slider bypass)

 

This should give me a variety of operation modes for my Les Paul, but most interesting:

 

[*] Standard mode: Both pots down, nice and dark, meaty Les Paul sound. It does this now.

[*] Telecasting Mode: Telecaster electronics mimicry when you pull the Volume pot. Bright bypass the volume pot, and weaken the neck pickup by cutting off one of the coils. Also since this puts the neck in single-coil mode, it brightens it too.

[*] Stratocasting mode: Pull volume and tone to activate Telecasting mode for extra brightness, but also use a single coil pick-up on the bridge so it gives a brighter tone itself (but doesn't have higher output than the bridge anymore). Should imitate a Strat.

 

Besides these there's of course the ability to use the bottom pickup by itself in single/humbucker mode and yank Volume to get a bright bypass; or single coil the top pickup with the extra brightness.

 

I actually think this'll give my guitar far more versatility than a simple coil tapping or series/parallel mod, or a phase switch mod. I'll have a number of selections of brightnesses, with a Telecaster or Stratocaster mimic setting. Still, as nice as it seems, I'm actually considering passing the guitar on shortly after finishing these modifications; I want to get an Epiphone Les Paul Studio to replace it and do the same mods to that, but with a few extra settings (like a separate bright bypass for the neck, to allow bright bypass in humbucker mode to give a little bit of a touch instead of a sudden dump into screaming telecaster territory). Probably give/sell it to someone I know who could use a good guitar, rather than just ebaying it.

 

Any thoughts on passing off a first guitar? Also if anyone knows where I can get 1 meg pots with a push-pull (DiMarzio doesn't make them and has no plans) I'd be interested, those could really give me a shot at rolling the tone up or down further. =D> Also the bright bypass should involve a .022uF cap and a 300k resistor across signal in and out of the tone pot right? What does the value of the resistor do to this, because I may want to move that +/-30k to give a brighter touch if possible....

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I think if I remember my electronic school stuff correctly,that the resistor makes the 500k (vol) pot act like a 250-300k pot like in a fender,Also the cap changes the tonal value to more fenderlike ones. I don't have my books anymore, So I can't give you the formulae , but changing these will vary the rc time constant,which will change the bandpass(frequency range of the cicuit). Hope some of this was helpful.

 

Edit I see you said tone pot,same difference, to the signal it will look more like a fender set up.

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Adding a resister in parallel with your pot will decrease the total resistance. In your case, 300K & 500K will equal 187K. The formula is Rt=(r1xr2)/(r1+r2), where Rt = total resistance. This shouldnt add any "brightness" to your signal. You would need to increase the resistance or decrease the capacitance to achieve less high cutting of your signal.

 

EDIT

Sorry, I reread your post and see that you're putting the 300K across the input/output, not across the pot. My bad =D>

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Adding a resister in parallel with your pot will decrease the total resistance. In your case' date=' 300K & 500K will equal 187K. The formula is Rt=(r1xr2)/(r1+r2), where Rt = total resistance. This shouldnt add any "brightness" to your signal. You would need to increase the resistance or decrease the capacitance to achieve less high cutting of your signal.

 

EDIT

Sorry, I reread your post and see that you're putting the 300K across the input/output, not across the pot. My bad =D> [/quote']

 

Adding an RC circuit.

 

.__
|P |------GND
|O |
|T |--------------OUT
|  |    |________
|  |       |     |
|  |    [Res]  [Cap]
|  |     __|_____|
|  |    |
|__|--------------IN

 

I know a higher value cap passes more lower freqs though (how does this go exactly? Please expand); not sure what a higher/lower val resistor does.

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You seem like a really bright guy,I don't have the math to explain this handy,maybe you could google up a basic electronics text and read it.

 

On the topic of 1st guitars,you should keep it,You probably have one of the nicer Special 2s around right?

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Yeah. It's basswood though, tone complexity is to the mids, the highs and lows attenuate fast. Parts on hand and already installed will total:

 

[*] DiMarzio DP161 Steve's Special pickups

[*] 500k DiMarzio push-pull pots

[*] Fresh tone cap

[*] Push-pull for Telecast mode (coil tap neck, bright bypass volume)

[*] Push-pull for coil tapping bridge

[*] Fresh pickup switch

[*] Sperzel locking tuners

[*] Graphite Nut

[*] Locking strap pegs

 

Not to mention the bitmo trio mod going into my VJ head as soon as I get my own iron, plus I'm going to go for a new OT and possibly redoing the electronics with higher quality components. ;)

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20 some years ago I built a Flying V with 2 hums,ea had a mini 3 way so you could select top or bottom or both coils,

that combined with the 3 way pickup selector gave me a lot of choices. I found that reversing the coils gives you a noise added but undeniably more defined signal cool...real scrappy sounding. Of course after playing with it that way I re wired it correctly!

Gosh I miss that Guitar!!

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Adding an RC circuit.

 

.__
|P |------GND
|O |
|T |--------------OUT
|  |    |________
|  |       |     |
|  |    [Res]  [Cap]
|  |     __|_____|
|  |    |
|__|--------------IN

 

I know a higher value cap passes more lower freqs though (how does this go exactly? Please expand); not sure what a higher/lower val resistor does.

 

These links may explain it better than I can.

http://www.projectguitar.com/tut/potm.htm

http://buildyourguitar.com/resources/lemme/

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The formulas for reactance (a measure of resistance to AC voltage) are, for capacitance: Xc=1/2piFC and Xl=2PiFL . You can go here to see calculators that allow you to input the values of capacitance, resistance, and inductance.

 

http://home.new.rr.com/trumpetb/audio/XLXCjs.html

 

When you combine resistance and capacitance in series, you create a resonant network. As you vary the resistance, you change the frequency that the RC network will pass (a tone control). Depending upon the values, the tone control will pass various freqencies to ground or to the output, depending up on the way you wire it. A wah wah pedal is a variable RC/L network that creates a notch filter (a device that passes a specific range of freqencies from low to high).

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Also since this puts the neck in single-coil mode' date=' it brightens it too.

 

Also if anyone knows where I can get 1 meg pots with a push-pull (DiMarzio doesn't make them and has no plans) I'd be interested, those could really give me a shot at rolling the tone up or down further. ;)

 

Also the bright bypass should involve a .022uF cap and a 300k resistor across signal in and out of the tone pot right?[/quote']

 

(1) Uhh... do these DiMarzios come with a three pole switch? Because with all you're planning to do with that one switch you need at least three poles (one for each pickup into coil split and one for the tone bypass = 3).

 

(2) Dunno why you need a 1M pot, it's not really going to give you anything all that useful.

 

(3) I'd blow off the caps and resistor here and just have the switch disconnect the tone control from the circuit. That should give you the brightest signal without taking any of the low end out.

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(1) Uhh... do these DiMarzios come with a three pole switch? Because with all you're planning to do with that one switch you need at least three poles (one for each pickup into coil split and one for the tone bypass = 3).

 

(2) Dunno why you need a 1M pot' date=' it's not really going to give you anything all that useful.

 

(3) I'd blow off the caps and resistor here and just have the switch disconnect the tone control from the circuit. That should give you the brightest signal without taking any of the low end out.[/quote']

 

A DiMarzio comes with a DPDT switch, which means I can coil tap one pickup and switch in a bright bypass circuit across the vol pot on one. The tone pot can coil tap the lower pickup.

 

A 1M pot will let me put more resistance between tone input and ground, passing more signal to output. When turned down, it puts more resistance between input and output, passing more signal to ground. Gives more range in both directions, might be overkill though.

 

I still want tone control in that mode. The RC bypass mimics part of the circuit in a telecaster (hence "Telecasting"; the other part of the circuit is a hotter bridge pickup, which I facilitate by single-coil tapping the neck) to give a sharp bright boost. Basically, because it bypasses highs across the volume pot's input/output leads, it levels out the attenuation curve on the highs; this mean when active the highs don't roll down as fast when I roll down the volume, and even max volume has some highs bypass the pot entirely (which still pushes PART of the signal to ground).

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A 1M pot will let me put more resistance between tone input and ground' date=' passing more signal to output. When turned down, it puts more resistance between input and output, passing more signal to ground. Gives more range in both directions, might be overkill though.[/quote']

 

Yes and no. You do get that extra 500K of isolation when the tone is at '10', but there's a law of diminishing returns here and you're already doing pretty well with 500K, especially considering that a real Tele only has a 250K pot. What you will find is that your tone control won't really start to have any serious effect until you dial down past '5'... Secondly, you are incorrect in that you do not get more range in the other direction; a short is a short and with the pot at '0' the 1M resistance is no longer affecting the circuit in any way (notice that the third lug of the pot isn't even connected to anything).

 

Your .022µF across the volume pot is going to let a LOT of stuff through. Normally the procedure is to put a .001µF here with no resistor, to do what you describe which is to allow the very high end frequencies through at all settings; this compensates for a certain filtering effect that takes place as you dial down the volume. Note that classic Teles had a .05µF tone cap which of course meant that you could get a more drastic rolloff as you dialed down the tone, i.e. less treble. Also the original vintage Teles had a switch position that engaged a .1µF cap to ground for a 'pseudo-bass guitar' kind of effect.

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Secondly' date=' you are incorrect in that you do not get more range in the other direction; a short is a short and with the pot at '0' the 1M resistance is no longer affecting the circuit [b']in any way[/b] (notice that the third lug of the pot isn't even connected to anything).

 

Ah right, the volume pot is a voltage divider but the tone pot is a variable resistor, my mistake!

 

Your .022µF across the volume pot is going to let a LOT of stuff through. Normally the procedure is to put a .001µF here with no resistor' date=' to do what you describe which is to allow the very high end frequencies through at all settings; this compensates for a certain filtering effect that takes place as you dial down the volume. Note that classic Teles had a .05µF tone cap which of course meant that you could get a more drastic rolloff as you dialed down the tone, i.e. less treble. Also the original vintage Teles had a switch position that engaged a .1µF cap to ground for a 'pseudo-bass guitar' kind of effect.[/quote']

 

Interesting. I've seen 560pF in parallel with a 300k resistor across the vol in/out leads for treble compensation with certain pickups (DiMarzio recommended this specifically with their DP161), which is what I assumed the Telecaster's bypass circuit was just with possibly different values. I have a 0.022uF and a 0.047uF tone cap available but went with the 0.022uF.

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Well I want a Les Paul sound, I'm just trying to throw in a switch to give it a Strat or Tele sound. The 0.047 was going to involve itself in a push-pull mod to kick in a deep, dark sound but I made the guitar sound like Slash's without it... and very close to Eric Johnson's GS (he normally plays a Strat though!) with the right settings. Hence the fancy wiring.

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The day i bought my Epi Wildkat i also played a Epi Lucille (BB.King) with a Vari-tone switch.

Didn't like it very much' date=' just made the sound thinner. Ended up buying the Wildkat.

 

Peter[/quote']

 

A good vari-tone switch is $40+ or so...I doubt very much they are putting high quality switches in the epi lucille. this is the one you want http://bigdguitars.com/varitonespec.htm . Or actually buid your own with only few custom caps if you are so inclined...probably better to build your own for going from a humbucker to single coil sound anyway. I've had several blues hawks and they all got very tele-like tones as well as the full range of p-90/humbucker tones....great little guitars....now I want another one!

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