The Watering Hole

I am really fed up with the treble loss that I get when I roll back the volume controls on my guitar.  I have tried various capacitors for treble bleed but none of them really work well, just doesn't sound right.

From what I have read, an FET unity gain amp built into the guitar just before the output jack would do the trick as it is the capacitance of the cable that is mostly doing the tone sucking when the volume pots are rolled back.

So, Howie (or any other electronics genius) do you have or know of an fet circuit that could be wired up to fit at the output jack of the guitar, small enough to fit easily, as of course I will need to put a battery in there too?

Jon


edit: this would seem to be ideal, but a real fucker to build into the tiny space in the cable  http://www.till.com/articles/PreampCable/index.html


edit2: Actually I wonder if that would actually do the trick as I would have thought the buffer needed to be in front of the guitars volume pot?????

OK Jon..What I'm about to say is very subjective and some would say WRONG!

First...A question (or three). What guitar are we talking about? What length of cable and finally, are there any pedals between guitar and amp/DAW?

My first and cheapest/easyist fix would to be lob the guitars volume pot and fit a 1meg (at least) large linear taper pot. Forget the 16mm versions unless space is a problem in the guitars cavity and make sure you get one with the right shaft length/diameter. When you think that a Les Paul has 500K pots as standard and older Strats have 250K pots, you can see why people say to fit treble bleed caps to older guitars.

The other thing to bear in mind is that a treble bleed cap will only work as expected if fitted with a suitable resister in parallel. (As seen on many Strats from the 80's/90's and Peter Greens Les Paul!

What you'll find is, with the new pot fitted, the overall sound of the guitar will be brighter with the volume fully up. With a linear taper pot and say a .22 cap fitted, the treble loss will be virtually nill until you hit about 1/3 volume.

The way my Strat is wired is as standard but with a 1meg volume pot with a 0.33 cap across it but with the added twist of having a mini toggle switch that puts the bridge pick-up straight to the jack output with nothing in between (a full blown bypass switch for the bridge humbucker). Doesn't matter where and pots or switches are set, hit the "hot" switch and watch the looks of absolute awe on the audiances faces as the amp sings :-)  8-).

Hope this helps.

The problem I have is that this is my les paul with "jimmy page" wiring, so it has all the push/pull pots for coil taps and phase etc.  Works really nicely, but no matter what variation of caps and/resistors I use for treble bleed it still loses too much of the treble as I roll the volume back.  

I'm thinking that maybe my only option is a buffered volume pedal (which would work) but then there's the added fiddle of having to be near the pedal everytime I want to roll back.

I've spent many hours trying different combinations of caps and resistors but none work good enough to give a satisfactory sound.

I've just thought of a way around this.

I could sacrifice one of the tone controls and wire that up as a master volume with a treble bleed cap on it.

I'm sure the reason the treble bleed isn't working on the the two volume pots has something to do with the various switching options as it works fine on a guitar with normal wiring.

Jon,

Basically, the closer you can get the boost or buffer to the guitar, the better.  In the guitar is the best in theory, though perhaps not in practice.  My thoughts are, that while what Andy says is true in general, with your fairly complex wiring inside the guitar, it probably would be better to add a boost or buffer instead.  

I actually had the idea of building a very small box boost/buffer that would mount on the guitar strap.  Not inside the guitar, but as close as possible and more practical.  But that would be more useful for a live player.  For recording, you can simply use the shortest possible cable from guitar to a good boost and or buffer.  

Now, this discussion could go on for a good while, but one thing has to be addressed up front when you want what you are after.  The design of the amp you are using is very important in the ability to clean up, and to a good degree, to clean up without tone lose.  But before that, you have to make SURE that your cables are good (all of them) and you are minimizing a potential negative effect that cables can have.  

This is both for home and live playing as I still do both.  The amp is th peavey classic and with other guitars it cleans up nicely to where I need it with volume roll back. Actually strapping a clean boost pedal to the guitar strap is worth a try and set it to unity gain

what do you think of this circuit....too basic or should it do the job?

http://www.tubefreak.com/buffer.htm


or this one has more parts....does that make it better?

http://www.till.com/articles/GuitarPreamp/index.html


and finally this would seem to be the one to build....but damn difficult to fit all the parts into the plug !!!!!!!

might have a go at this one   http://www.till.com/articles/PreampCable/index.html

Now this is really odd...and also very pleasing.

I thought I would try an experiment by wiring up a master volume control on the guitar.  Of course I did not want to do this for real on the guitar so I wired up an external volume pot that I had lying around (didn't even know the value of it).  So it has a jack plug on it that goes into the guitar and then a socket on the output for my normal guitar lead to the amp.

If I adjust the guitar volume from this pot there is no loss of treble whatsoever when I roll back.  Even more bizarre (which probably isn't bizarre at all, just unexpected) if I set the master volume at 85 %, then my guitar volume controls act as I had wanted all along with no treble roll off at all when rolling back the volumes of each pickup.  

So, once I do a bit more testing I will sacrifice one of the tone controls in the guitar and convert it to a master volume control.

I put my meter on the external pot as there are no markings on it and it is 100k


So can anyone explain how this is working? Obviously it is changing the impedance of the guitars output, but is there a correct value that I should be using for the master volume rather than the 100k pot that I picked up by chance.

This is like a miracle, really is.  At last continous treble when rolling back the volume without needing to use a treble bleed circuit at all and the tone is full and rich...nothing lost.

Excellent !   ;D

When I think about it, isn't that the way that all external volume controls work?  If you used a volume pedal, the same thing would happen--no loss of treble, no change in the overall tone.  I think when you stick it inline, between the pickups and the output jack, the behavior is different.

Sounds like whatever the impedance is at 85% is what you need to add before the jack as it "fixed" your guitar vol pots.
or is that too simplistic ?

fingers — Apr 05, 2010Sounds like whatever the impedance is at 85% is what you need to add before the jack as it "fixed" your guitar vol pots.
or is that too simplistic ?

That would seem too simplistic, but that is actually what is happening, so that's a good idea that is so simple I don't know why I didn't think of it...all I need to do is measure the 85% resistance value and get a resistor for the same value and solder inside the guitar....(or maybe a little trim pot might be more sensible). Good idea

You could rig up an experimental setup  to check you have the right resistor/trim pot
externally before you operate on the guitar itself.