Single tone knob question

[dehughes]

Hey all,

So, I've given the typical Brown Deluxe tone knob setup a chance, but I find that for the most part it seems to impart a honky tone (think the letter "R") to the channel, and I'm wondering if there's an appreciable difference between the 6G3 and 5E3 single tone knob setup. Or, perhaps there is a more versatile single tone knob wiring? I'm mostly looking to add and subtract upper mids instead of the more growly, lower midrange. Any suggestions?

Or, perhaps this "R" tonality is just part of the Brown Deluxe vibe...but I fail to see on the schematic why this would present itself....or is it just a result of there being no typical TMB tone stack between the triodes???

[10thTx]

An option to consider is to use a dual 500k pot and a James Tone stack. I like the JTS and it does shape the mids more than the typical FTS.

I have built one into a dual 500k pot before mounting all the components on the pot.

Plug the values I put into the JTS into the Duncan Tone Stack calculator and move the treble and bass controls from 3 to 8 . I think you'll find the mids shift considerably.
http://www.duncanamps.com/tsc/

With respect, 10thtx

[Andy Le Blanc]

On Huss's HiWatt page, there a very simple and early example of the HiWatt
presence control. Its a ground referenced pot., one side is an old fashioned tone
control after a gain stage, the other side dials the cathode bypass cap of the
same stage, so it effects the gain structure. The wiper on the pot. is grounded.

The old fashioned tone is hi impedance, be careful, you'll loose more than you
gain over compensating with tone controls. Check out the bargain bin amp
at schematic heaven, lots of tone control ideas there too.

[dehughes]

Very cool 10thTx and Andy...thanks.

So, I came across the Gibson GA30RV schematic and compared the mid knob on that to the Matchless Chieftan, and realized they are virtually identical. I've heard good things about this control, and figure that with a Cut knob in the power section I might be good to go. I'll give it a whirl later...but I do have a question:

Does it matter if the tone knob comes "before" or "after" the volume pot? That is, would one yield a different/better result?

[skyboltone]

Very cool 10thTx and Andy...thanks.
I do have a question:

Does it matter if the tone knob comes "before" or "after" the volume pot? That is, would one yield a different/better result?

The tone pot wiper should be connected to the coupling cap of stage one, the wiper of the volume pot should be connected to the grid of stage two.

There will be inter action between the two but having the volume pot feed stage two is better in my experience.

And I agree that 10thTx has an interesting scheme there. I'll take a shot at it one of these days.

[sliberty]

Just as another alternative....

I really like the Vox rotary switch couple cap selector. Very effective, and no loss of gain like most other tone controls.

[dehughes]

Just as another alternative....

I really like the Vox rotary switch couple cap selector. Very effective, and no loss of gain like most other tone controls.

You mean the Matchless DC30 thing?

[sliberty]

I think VOX might take exception with attributing it to Matchless, but yes that's the one.

[klingo]

You could simulate the chieftain/gibson/etc tone control with Duncan TSC. go to big muff, dime the tone control, make R2 10/100 Mohms, select your favourite caps/resistors value and an appropriate output impedance Zsrc. Imagine you have a 1M vol pot before it at noon and try a 200K Zsrc
of course you will only see the max mid scooped response this control can give (no pot from cap to ground)

[dehughes]

On Huss's HiWatt page, there a very simple and early example of the HiWatt
presence control. Its a ground referenced pot., one side is an old fashioned tone
control after a gain stage, the other side dials the cathode bypass cap of the
same stage, so it effects the gain structure. The wiper on the pot. is grounded.

The old fashioned tone is hi impedance, be careful, you'll loose more than you
gain over compensating with tone controls. Check out the bargain bin amp
at schematic heaven, lots of tone control ideas there too.

Hey Andy, is this the schematic you were thinking of?

http://mhuss.com/Hiwatt/Schematics/DR_Pre4Input_v0.gif

[Andy Le Blanc]

http://mhuss.com/Hiwatt/Schematics/DR_Pre4Input_v0a.pdf

late 60's Four input preamp I

I've seen similar in a magnatone but with the treble bleed before the stage

[dehughes]

http://mhuss.com/Hiwatt/Schematics/DR_Pre4Input_v0a.pdf

late 60's Four input preamp I

I've seen similar in a magnatone but with the treble bleed before the stage

Ah. So you think that'd work on a Volume pot as well, or were you thinking of that as it is on a cathode in my amp?

[dehughes]

So I wired up the tone knob a la the Moonlight schematic:

http://amps.zugster.net/articles/tone-stacks

This is getting really close....if i could get this tone stack to be a bit brighter and/or more scooped in the mids, I'd be there. Really, if it "kept going" when getting brighter, I'd be just about where I want to be. Any suggestions? Larger cap? Larger resistor to ground? Tone stacks aren't my strong suit....

[Structo]

Thanks for that link.
That AMZ tone stack looks very good.

[dehughes]

Thanks for that link.
That AMZ tone stack looks very good.

AMZ? Which were you referring to?