1 pot "additional" to Thunderchief - please help m

[Marcos - Munky]

I will start to build my Thunderchief in this week, and I will use a enclosure that I already have here. But it's drilled for 3 pots. I need a suggestion for the 3rd pot. I was thinking about a tone control, but I think this will kill the two low pass filters function (simulate the speaker). I was thinking about a mid cut too. And diodes in output to ground, anybody tried? Anybody have a very simple mid cut circuit or any 1 pot suggestion?

[B Tremblay]

You could add in the Presence control.  We hard-wired it at maximum for simplicity, but there were some subtle variations available when we tested it with a pot.

Replace the 4k7 to ground below Q3 with a 5k-B pot.  Lug 3 connects to the 4k7 and 100k, Lug 2 connects to the existing 100n (with the other cap lead still to ground), and Lug 1 to ground.

[Nasse]

There is one modification already suggested at runoffgroove (that "variac" idea), adds one knob

Another suggestion there is adding tone control, and just started wondering if you could use BMP one knobber, can´t see why not

[Marcos - Munky]

What you guys think it's better, the Presence pot, Variac mod or Big Muff tone control?

[smoguzbenjamin]

I say presence

[B Tremblay]

The BMP tone control, in it's stock form, will change the sound quite a bit.  If you decided to add it, spend some time with Duncan's Tone Stack Calculator to flatten the response when the control is at its midpoint.

I didn't try the "Variac" control during the development of the 'Chief, but I'm sure that it would have a more pronounced effect than adding the Presence pot.

Luckily, all three are easy to remove later if you decide you don't like the results.

[Eddie]

What about changing the 15 k resistor and use a 20 k Pot instead at the final Lowpass filter?

BTW I use the thunderchief without the LPF and go straight in my poweramp. I need a little more treble to get a more open Van Halen I Sound.

Correct me if I´m wrong but the original marshall tone stack has a mid scoop when all knobs are on ten, right?Maybe I miss this mid scoop.
I would like to tweak the thunderchief to get a little more agressive sound.

One new Clip of my thunderchief with a Phase 90 in front:

right click&unzip!Sloppy playing but great Sound!

http://forum.musikding.de/attachements/Thunderchief3.zip

Eddie

[RDV]

Wwwhhheeee!!!
That was fun!!

You know it's amazing how most don't realize what a huge role reverb played in getting that sound on the first few Van Halen albums. Ted Templeton rocks!

RDV

[Marcos - Munky]

I think I will use the tone control. But there's a problem, I don't know anything about frequencies and all that is used in the Duncan TSC. Anybody can give some suggestions for the values? And what about some values for mid scoop?

[RDV]

You know if you'd like to truly simulate a Marshall you could do the presence control & a 3-band Marshall style E.Q.

I bet that would rock!

RDV

[smoguzbenjamin]

uhm... well look at the graph, Marcos. It's more of 'how does my graph look?' and then breadboarding it and seeing if you like it. If you can pull the middle of the graph down you've got a mid scoop right there

[Marcos - Munky]

I played a little and got three "cool looking" graphs. The first line is pot in zero, the secound is pot in middle and the third is pot full. What do you guys think about the graphs? Wich one to choose?

http://www.geocities.com/munkydiy/tone.jpg

[Marcos - Munky]

[Marcos - Munky]

[RDV]

I'd install some sockets & adjust to taste.

RDV

[Marcos - Munky]

I will try. I will finish a overdrive that I'm building and will start to build the Thunderchief in this week. After I finish it, I will post the results of the tone control here.