John Mayer Two Rock!

[Karl]

Does anyone know what the contour control is for on this amp?

[img461]http://www.guitarsetc.net/amps/tworock/ ... _front.jpg[/img]

Does anyone have a schematic for a contour control?

[benoit]

Check out this link.

https://tubeamparchive.com/viewtopic.ph ... ht=contour

You could probably PM novosibir and ask nicely, I think he could probably explain it pretty well.

[VacuumVoodoo]

It's also known as "tilt" tone control. An opamp based version:

http://members.tripod.com/roymal/ReverbTone.htm

The "mojo" is in finding proper turn over frequency for use in a guitar amp.
I leave it to you to figure out how to implement it with tubes

[tomrasdf]

Anyone ever seen under the hood of one of these? Wot's the big idea putting the gain so far away from the tonestack? Is it based on a new and different schematic or do they just like long grid wires?

[Karl]

This is the only picture I have found of the inside.

[novosibir]

Here's still another one:

https://tubeamparchive.com/download/file.php?id=2330

Larry

[Structo]

What is that they use for their boards?
Looks like a laminate like for kitchen counters.

[gearhead]

That's an upcharge; the vintage-woody motif. LOL.

The origin of Formica was for electrical insulation; a moldable replacement for the mineral MICA. Some here have used sheets from Home Depot for boards too. There's a thread on this somewhere, a ways back.

[novosibir]

I wouldn't trust this material!

When it's wood based and is sucking moisture, then it might become to a semi conductor

Larry

[gearhead]

I doubt it is wood based; a faux wood grain. Looks like some variant of Formica, which is an insulator (it it's the right one).

Edited- found one thread

https://tubeamparchive.com/viewtopic.ph ... ht=formica

[FUCHSAUDIO]

It's not wood based. It's actually a composite, and it's very stable, compared to the Fender fiber board, or wood. It was done by Dumble in the past on most ODS amps.