Champ volume adjustability??

[WoodyStrat]

How would I extend the range of the volume pot on my Tweed Champ? I built this clone and have played it extensively for the last 3-4 years and just love the thing! However, I would like more adjustment on the volume knob. I am sure that I am not the first. I want to have a more variable volume control between what is now “4” and “5” on the dial. It would not have to be a huge change, but say adjustable between “4” and “6” maybe. Any ideas?

[Kevbo599]

Would you like to make your Champ louder or are you trying to increase the headroom before it starts to breaks up?

[guitarcapo]

I would think that a lower value pot would have a finer sweep between values...like say a 500K pot would have a more fine tuning than a 1 Meg pot.

Also adding a resistor across the lugs of the volume pot would do this.

For example adding a 1M resistor across a 1M volume pot creates a 0-500K sweep with a finer touch because the sweep is now from 0 to 500K instead of 0 to 1Meg.

Personally I like to add a bleed capacitor across the volume pot of my tweed Champ. It gives you more brightness when you turn down and also extends things this way.

[WoodyStrat]

Originally Posted by Kevbo599

Would you like to make your Champ louder or are you trying to increase the headroom before it starts to breaks up?

Actually niether. The most usable range on the volume knob for me is between 4 and 5. Between these two settings there are some pretty big changes in volume/gain. What I would like is for the change in volume that happens there to happen across a wider sweep on the volume knob. So for example, the volume could be the same as it is now at "4" but at the current "4.5" setting, that could happen instead at "5" and what was the volume at "5" could now happen at "6." The numbers are not important but having greater adjustablity with in that defined range is.

Originally Posted by guitarcapo

I would think that a lower value pot would have a finer sweep between values...like say a 500K pot would have a more fine tuning than a 1 Meg pot.

Also adding a resistor across the lugs of the volume pot would do this.

For example adding a 1M resistor across a 1M volume pot creates a 0-500K sweep with a finer touch because the sweep is now from 0 to 500K instead of 0 to 1Meg.

Personally I like to add a bleed capacitor across the volume pot of my tweed Champ. It gives you more brightness when you turn down and also extends things this way.

So a lower value volume pot would give a finer sweep. I guess I should take some resistance measurements and see what happens at different settings and use that as a guide. I had not thought about the treble bleed idea but that may be a reasonable mod as well! Thanks!

Any other ideas lurking about?

[TweeDLX]

Actually, increasing the headroom a bit would result in the same thing. The amp would still overdrive as always, but at a somewhat later point, thus increasing the range/sweep of the pot. Using a switchable cathode bypass resistor with a .68uf/25uf/no cap at all type set-up would give you some real tonal flexibility. I did this to mine and like it. Some people may disagree, but IDGAFF.

[tlpruitt]

Make sure you have a 1 meg audio taper pot in that champ. Also, not all audio taper pots have the same sweep so you might try a different brand audio taper pot. Even a different audio pot of the same brand and pot value may have a different sweep.

[TweeDLX]

Even a different audio pot of the same brand and pot value may have a different sweep.

Very good point!

[guitarcapo]

I would think a 100K pot would give you an even wider sweep...I guess it wouldn't be as bright and clear wide open that way but if you are leaving your amp between 4 and 5 all the time that wouldn't matter anyway.


My biggest problem with a Champ amp design is that they sound muddy to me with less clarity when they aren't dimed. An old tech told me: "Champs only sound good with the volume on 12...adjust for volume at the guitar"
So anyway I have had the best luck with adding a cap across the volume pot.
Buy a whole bunch of different value caps and try them out. Not only do they increase the range of the volume knob's sweet spot....they add clarity to the cleans at a lower volume....think blackface Vibro Champ cleans over tweed champ cleans in sound. The cap has no effect at the higer settings when the volume is dimed.