Schematic question

[islandamp]

In the enclosed clip of a schematic I'm experimenting with, the gain control is showing the top of the pot jumped to the sweeper. Is this something done on foreign schematics or did they really jump the 2 lugs together? I,m a little confused on this drawing.

[Bob-I]

Sorry but there's not enough schematic to tell what's going on.

[iknowjohnny]

yeah, not enough to see. But they're simply wired as variable resistors, so could they be connected to some clipping diodes?

[jelle]

That looks like a Koch drawing!

Just post it.

[Ears]

I'll hazard a guess that they're just adjustable inputs of a summer or mixer.
Adjust to provide desired balance.

[islandamp]

Its a Koch schematic,, I just posted the relavant section to avoid confusion. Its the gain pot from V1 to V2. Disregard the 2nd pot as its a 2 channel amp. The v1 pot top is conected to v1, bottom is ground, and wiper jumps the top and goes on to V2.

[jelle]

Pic is easier to follow....

[jaysg]

Looks to me like a split point where you have two volume pots either being switched 'A or B,' or feeding other circuits with independently adjustable levels. Are they panel pots or internal?

[jjman]

Rather than thinking of them as jumped to the wiper, think of them as variable resistors jumped to the input end of the pot. It means nothing electronically if the pot works properly. If the wiper looses contact the jump approach maintains the minimal level of conductivity of the “resistor” which is equivalent to the value of the pot.

I always use the jumped approach.

[FUCHSAUDIO]

I've seen this used in various Fenders, Koch's and others. Using a relay, allows you to vary the gain of the circuit by swapping the bottom resistor in a stacked pair of resistors. A fixed resistor on top, a variable on the bottom.
By changing the pot value or the top resistor value, you vary the loading on the circuit, and can also vary the gain and tone.

Not sure why they use the potentiometers as variable resistors, and not select the output of a couple of pots used normally, but in certain circuit locations I can see it being a potentially lower noise solution for gain switching.

[islandamp]

I tried wiring the pot as a standard gain pot, like a Plexi and the amp sounded thin and horrible. This variable resistor method sounds much thicker and much better, but theres very limited headroom this way as compared to the standard gain pot wiring. Past 2 is crunch, 3-4 is cranked Plexi, above 4 is Carvin Legacy full gain.