treble loss when rolling back volume knob???

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Woody777

New member
I know the 50s mod remedies this, but are there other options? I was reading in the archives about an electronics upgrade kit. What do people use (if anything) to remedy treble loss when using the volume knob to clean up your tone? What are the pros and cons of each method?

Thanks!
 
Re: treble loss when rolling back volume knob???

About the only other approach I can think of is to put a buffer between the pickup and the volume pot. Personally, I prefer to avoid having batteries in my guitar.

Most of my guitars have a treble bypass cap and I'm quite happy with it.
 
Re: treble loss when rolling back volume knob???

I think I'll just try the 50s mod and see what I think. I don't use the volume knob much as it is, but only because it muddies things up! Hopefully the 50s mod will allow me to use my volume knob more.
 
Re: treble loss when rolling back volume knob???

I use a 0.001 microfarad cap wired between the "grounded lug" and the pot casing (no direct connection Lug- Case as is the norm). THis way I lose less treble, but can still use the Vol knob for warm, low output cleanish tones ;)

Btw: this is essentially the same as Arties Link, just witha different cap value ;)
 
Re: treble loss when rolling back volume knob???

I use a slightly different version of the treble bypass mod that puts a resistor in series with the capacitor. I A/Bed the conventional mod with the serial mod using a push-pull pot, and liked the serial version better. Basically, it allows some highs to come through, but the resistor limits the amount of highs that bypass the pot:

http://www.kinman.com/html/toneWorkshop/perfectGuitar.htm#volumePots
 
Re: treble loss when rolling back volume knob???

There are only three real ways, buffer it before it hits the volume control like
aleclee said, use the '50's which just kind turns the tone control up as you turn the volume down, it also reduces the effectiveness of the tone control when turned down when the volume is turned down as well, or use a RC or C across the hot and wiper of the volume pot, the last one tends to create a treble boost at lower volumes, if scaled correctly though it can just presevre the high end, but that's only at one setting, at lower settings it creates an actually boost. It's personal preferrence really, the '50's is the easiest to implement (no extra parts), then comes the RC or C filter, then comes the preamp/buffer and volume control replacement ... that is probably the most natural sounding one (given the pre amp of course), then comes the '50's mod, and then the high pass filter set up.
Then there is going without it, and just liking that, and many do. I have a bunch of stuff worked up and put into a presentation, but it's probably still a ways off yet ... that whole time permitting thing ... :rolleyes:
 
Re: treble loss when rolling back volume knob???

MattPete said:
I use a slightly different version of the treble bypass mod that puts a resistor in series with the capacitor. I A/Bed the conventional mod with the serial mod using a push-pull pot, and liked the serial version better. Basically, it allows some highs to come through, but the resistor limits the amount of highs that bypass the pot:

http://www.kinman.com/html/toneWorkshop/perfectGuitar.htm#volumePots
Click to expand...

On a single coil Strat, I've tried a .0015 cap alone across the terminals, a .0022 cap in parallel with a 100k resistor like the S-D treble bleed, and a .0011 cap in series with a 130k resistor (the "Kinman mod").

The .0015 cap alone worked OK. The S-D mod turned out to be a treble boost rolling the volume down, plus the resistor in parallel seems to modify the taper on the volume pot somewhat (I'll let Kent go into the technical side of that if he wants to ;) ). On my Strat with vintage output single coils, the Kinman mod is the most transparent. There is a very slight loss of high end as I roll the volume down, but that works fine for me.

Over on the Les Paul forum, guys seem to use even smaller caps like 680pf for a treble bleed. Also, the S-D mod may work better with humbuckers or high-output pickups than it did for me.

Chip
 
Re: treble loss when rolling back volume knob???

There is a fourth way that Kent did not mention, but it requires going to non-standard pickups. If you put fewer turns on the pickup, it has lower impedance (mainly lower inductance) and you can use smaller value pots which are not loaded by the cable capacitance. The output level is less, and so you will need a preamp before going to the first tube stage. But the preamp does not have to be in the guitar; it can be located at the amp; after all the point of low impedance is that you do not have problems with cables. The preamp does need to be solid state (but not JFET) to get the best signal to noise ratio. Remember the Les Paul Recording Professional? It used low impedance pickups and a step up transformer at the amplifier (in one of its production years, anyway). The transformer has its own problems, and of course it never caught on. It is better to do this with an ss preamp. This volume/tone sensitivity thing is a result of using 1950s technology, but it is a real pain to change, and i do not think anybody will.
 
Re: treble loss when rolling back volume knob???

sanrafael said:
There is a fourth way that Kent did not mention, but it requires going to non-standard pickups. If you put fewer turns on the pickup, it has lower impedance (mainly lower inductance) and you can use smaller value pots which are not loaded by the cable capacitance. The output level is less, and so you will need a preamp before going to the first tube stage. But the preamp does not have to be in the guitar; it can be located at the amp; after all the point of low impedance is that you do not have problems with cables. The preamp does need to be solid state (but not JFET) to get the best signal to noise ratio. Remember the Les Paul Recording Professional? It used low impedance pickups and a step up transformer at the amplifier (in one of its production years, anyway). The transformer has its own problems, and of course it never caught on. It is better to do this with an ss preamp. This volume/tone sensitivity thing is a result of using 1950s technology, but it is a real pain to change, and i do not think anybody will.
Click to expand...

Yeah, I remember the LP recording ...odd bird that one ... had a lo-z output tranny in it, and some models had the hi Z out as well ... What you mention here is essentially the concept (or partly so) behind the EMG thing, also it's the same concept if you use the preamp (the preamp accomplishes the same buffering) ... Speaking of which Don Tillman has a very cool, small, simple JFET preamp (Yes they do sound better, hell, a JFET has 12ax7 like response ... very cool, and doesn't alter the phase like opamps do).
Not a gain booster though, not enough headroom from a 9V, but it's got a 3M input and pretty low output z ... just enough to be natural sounding.
Check it out at his page ... www.till.com ...he also has a cool applet on there showing the difference in string/phase/pickup/harmoinc positioning.
 
Re: treble loss when rolling back volume knob???

Kent, I believe Gibson LP rec at first had a low Z output only and no transformer inside. (You use fewer turns on the pups, low resistance values for the pots, etc.) Later, they put a transformer inside so that it would have a hi Z out as well and could be used with standard amps without an external transformer. It is easier to make a low Z pup, and they are better in every way, except that they will give poor signal to noise ratio when used directly to a tube preamp because you would need another tube stage just to get up to the voltage level of the Hi Z pup. The JFET preamp will also not give such good SNR when used in this way. The junction transistor is a different kind of device that can be used in the correct circuit to give excellent signal to noise ratio in a circuit with a lot lower impedance. Thus an op amp with a junction transistor input is the choice for a low impedance circuit. It also happens that they reproduce the signal with very high accuracy; there is no phase shift in an op amp preamp with a reasonable gain.

The question of how the preamp should "sound" is an interesting one. It seems to me that your tube amplifier gives you the sound you want. Therefore, if you need to add a preamp (not an effects box, just a preamp) between the guitar and amp (either inside the guitar or at the amp) you want it to alter the sound as little as possible. Just like a piece of wire with gain, as the expression goes. In my experience, a good op amp is the closest thing to this. This is based on listening to a lot of circuits, and the specifications. (LM837 gives .0015% distortion, very low noise)

As an engineer, I do understand the advantages of electronics in the guitar, expecially a bass when it is important to have convenient control over equalization. But i kind of like a completely passive instrument. One of Murphy's laws is that batteries only go dead when you need them most and do not have a spare! But that is a poor excuse; in reality, I just like the idea of a passive instrument better. And the best way to get rid of the volume/tone interaction with a passive instrument is to go to lower Z pickups and controls. It also really reduces the hum problem, which I think was the main reason for the LP rec. It is a kind of odd system since you need an ss pre amp in front of a tube amp, and nobody is going to do this. But it really is a good solution.
 
Re: treble loss when rolling back volume knob???

Woody777 said:
I know the 50s mod remedies this, but are there other options? I was reading in the archives about an electronics upgrade kit. What do people use (if anything) to remedy treble loss when using the volume knob to clean up your tone? What are the pros and cons of each method?

Thanks!
Click to expand...

Another method, if you're after a great rock rythym and lead tone, is to plug your guitar into a Boss DS-1 set to about 1/2 way, and just tweak the settings on the DS-1 and on your amp until you can leave the DS-1 on all the time (as Steve Vai and Joe Satriani do) and then control everything with your guitar's volume control.

Lew
 
Re: treble loss when rolling back volume knob???

I'm not a big fan of using high pas filters on the volume pot to retain highs. I tried a 560 pf cap in my Hamer, and there was way too much treble when the volume was turned down, even though the BBQ/A2P is a warmer sounding pickup set. When I get around to rewiring it, I'm going to wire it with the 50's mod to see if I like that a little better.

Ryan
 
Re: treble loss when rolling back volume knob???

sanrafael said:
Kent, I believe Gibson LP rec at first had a low Z output only and no transformer .................
Click to expand...

I remember the pup's were lower Z'ed now that you mention it, but I thought that the tranny was for lowering even further for direct connection into the board, and that the pups went direct to the amp for regular use. I don't know, they had a couple versions, and I remember the switching system was odd. I think I've still got a schematic of the one with the tranny, bass, treble, volume, 3 way switch, and decade switch ... man, I swear there was something else on it also ... maybe not. The caps were pretty large values, so that would match with the pups being low impedance.

It is easier to make a low Z pup, and they are better in every way, except that they will give poor signal ................
Click to expand...

I wasn't referrencing the JFET's use to this application ...

The junction transistor is a different kind of device that can be used in the correct circuit to give ................
Click to expand...

I believe what comes to mind is that fact that many different stages are incorporated in an opamp, and the use of negative feedback to control the gain (whether it's used as an inverting amp or non-inverting amp) tends to produce it's own artifacts. See, we are kinda speaking of two different things here ... you are describing what may best suit a low Z instrument ... I'm still talking hi Z ... The main objection to the opamp is the supply voltage being used up hence many people going to 18V rather than 9V for more headroom, but opamp amps have a interesting habit of one side being pushed a little further than the other and the thing doing this little phase inverted clip thing.
It sounds generally really harsh and gritty, unlike the JFET's which are a bit smoother about it. Keen and Tillman both spoke of this, and I've heard what they are talking about ... It does depend on the opamp, or Fet used, but generally I stand by the reasoning of opamps for overdrive/distortions, and Fets for clean with little to no gain (buffering), but then again BOSS uses both FETs and Bi-Polars as buffers in their pedals, and generally they work very unobtrusively. It appears we are talking to different apps here.

The question of how the preamp should "sound" is an interesting one. It seems to me ................
Click to expand...

I've learned to be a little leary of specs taken to intently ... sound refers here to unwanted colourations and other distortions ... but I get your point ... hey if it works for you great.

As an engineer, I do understand the advantages of electronics in the guitar, expecially a bass when ........................
Click to expand...

I like to keep it passive also, but whether that's the best solution or not is really a matter of choice, the LP recording was made for basic *clean* playing, high gain metal ... not! And there is nothing wrong with what it was created for, but the majority of people use hi Z pups, and as such have to deal with the conditions set up by them. I chuckle, because I've seen first hand Murphy's Law in action ... :laugh2:
I'd save the clean opamp stuff for acoustics myself, but that's just me.
Hum, good point, but considering I'm a humbucker and then shield it to death kinda guy, that works for me ... another important point ...If you like the sound of a certain pup, well trying to find a way to recreate it in a lower Z version is kinda shooting yourself in the foot ... as it would be cheaper and easier to put into action one of the other methods, and for that I still stand that Jets are better than opamps for clean buffering with small amounts of gain for hi Z pups. Interesting note about the bi-polars in front of an opamp for low Z pups though ...hadn't thought about that. :cool3:
 
Re: treble loss when rolling back volume knob???

MattPete said:
I use a slightly different version of the treble bypass mod that puts a resistor in series with the capacitor. I A/Bed the conventional mod with the serial mod using a push-pull pot, and liked the serial version better. Basically, it allows some highs to come through, but the resistor limits the amount of highs that bypass the pot:

http://www.kinman.com/html/toneWorkshop/perfectGuitar.htm#volumePots
Click to expand...

Absolutely!
Experiment a bit with the R and C values for best balance, but this method maintains normal pot action and does not give a radical tone change with pot position. Simple, too. (I've done this for several years, maybe before Kinman.)
:newangel:
 
Re: treble loss when rolling back volume knob???

Yep, depending on how deep ypour understanding of electrical engineering is :D

Either way, we´ve wandered :offtopic: ;)
 
Re: treble loss when rolling back volume knob???

Kent S. said:
There are only three real ways, buffer it before it hits the volume control like
aleclee said, use the '50's which just kind turns the tone control up as you turn the volume down, it also reduces the effectiveness of the tone control when turned down when the volume is turned down as well, or use a RC or C across the hot and wiper of the volume pot, the last one tends to create a treble boost at lower volumes, if scaled correctly though it can just presevre the high end, but that's only at one setting, at lower settings it creates an actually boost. It's personal preferrence really, the '50's is the easiest to implement (no extra parts), then comes the RC or C filter, then comes the preamp/buffer and volume control replacement ... that is probably the most natural sounding one (given the pre amp of course), then comes the '50's mod, and then the high pass filter set up.
Click to expand...
So to recap, there you go, using lower impedance pup's isn't an option if you like what you have. Look again ... at the above post ... it's all there listed in effect created, and in easy of implementing into your situation.
An RC or just C across the volume will be a treble boost at lowered volume settings, the '50's will retain the normal highs at the expense of the tone control not cutting as deep when the volume is lowered; a buffer between the pup selector and replacing the volume will a lower impedance pot will give the most natural retention of highs without any lessening a tone control action or boosting of the treble (tone stage hooks *before* buffer).
 
Re: treble loss when rolling back volume knob???

rspst14 said:
I'm not a big fan of using high pas filters on the volume pot to retain highs. I tried a 560 pf cap in my Hamer, and there was way too much treble when the volume was turned down, even though the BBQ/A2P is a warmer sounding pickup set. When I get around to rewiring it, I'm going to wire it with the 50's mod to see if I like that a little better.

Ryan
Click to expand...

I experimented with different pf caps till i found the one value that kept the treble balanced as the vol knob was turned down ... The 160 pf cap was right for my twin bucker guitar. Higher values made things too trebley as vol was turned down, just as you say.
 
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