Dealing with distorted guitar volume - volume pedal?

[ptchristopher3]

Hi Nea,

The OP is happy with his sound. I see not reason to tell him he is not.

He wants to control the volume of the resulting sound from the RAT. This is done by placing a volume control after the RAT via a pedal, or volume control on the amp, or volume pedal in the FX loop, or power soak, or ear muffs for the audience.

The RAT uses a diode pair to ground. This works very much like a pair of bypass diodes on an op-amp does. It creates a clip of the signal to the point that, in many cases, the guitar volume only affects the slope of the sides of the clipped wave until you get WAY down on the volume control.

This is both the fact of the matter, and consistent with the OP’s description of his experience. It happens.

A much milder overdrive (and there are many, as you have mentioned) can work far differently.

To stay with your nostalgia vibe, consider something like a pedal which actually drove an FET to distortion, vs. using a diode pair to clip the signal. This can result in a guitar volume control that provides some practical control of the overall amplitude of the signal after the effect. But it will still change the way the effect sounds as you change volume from the guitar.

Take a look at such a setup on a scope, and listen with some care, and you will notice that the guitar volume does not at all magically control the amplitude of the effect output. It changes both the overall amplitude (to a pretty good extent), and it definitely changes the shape of the signal coming out of the effect.

I understand the enthusiasm of devotes of some pedals, but the guitar volume does not act as a volume control for the final output of the effect box.

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For laughs,...

One could conceive or even make a pedal that splits the guitar signal.

Then one of the split signals could be used as a control to a VCA and indeed control the overall output of the final effect box output. (Sort of like the old Ross gray compressor did, but in reverse.) Thus the amplitude of the guitar output could be rectified and used as a VCA control signal. Look at the Ross schematic to see how this works.

The other half of the split signal could be buffered and also run through a VCA to make a [somewhat] constant input for a drive circuit.

But a what a noisy godawful mess that would all be. And even if digitized, the poor signal quality as the guitar volume knob was tuned back would make a real mess.

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As for fuzz in the 60’s - Sure. No volume pedal. But the OP is seeking a different result. And that is effective dynamic control of the volume of a carefully crafted sound that uses an overdrive pedal of his choice.

Could he be happy with a Brain Seltzer pedal? Possibly.

Is this the subject at hand? Not as best I can tell from the OP.

Chris

[ptchristopher3]

VCA - voltage controlled amplifier
FET - Field effect transistor

[ptchristopher3]

I thought the Nocturne (that you mentioned) used a single 741? Nea, can you comment on if this is the case or not?

I have never seen a schematic, so can definitely be mistaken on this.

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EDIT: So the Nocturne Jr Barnyard, that seems to be very popular with some, (and staggeringly immaterial to the OP’s question) touts being FET based and also using some sort of beloved diode variety. A more “musical” diode I am certain.

Whether one distorts via genuine “overdrive” of one or more components, or uses clipping diodes, OR both, the effect can be perceived as providing some “compression” since both methods result in a max signal amplitude being reached before the max output amplitude of the guitar. And surely some find this a very pleasing thing.

Anyway, it may very well be that the original Noctune (in seemingly several sub-varieties) used a 741. It may also be that the Nocturne Jr Barnyard uses FETs and seemingly diodes as well.

I used to make on-board guitar pre-amps using a single FET and a diode pair. It is amazing the variety of drive effects you can get by varying the extent to which the FET is driven, AND the extent to which you let the clipping diodes get involved.

NONE of this changes the OP’s original issue. The overall amplitude of the result of the “drive” is adjusted AFTER the effect, not before.
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