Behringer VT 999 Vintage Tube Monster Pedal

[olddawg]

These are on sale at Amazon for $49. Behringer VT 999. I couldn’t help myself. People have been raving about these things for years and you could scarcely buy the case for that. Unfortunately the damn thing sounds like a bad Muff to my ears. Does anyone have the REAL schematic for it? A lot of people suggest changing the tube and using a 12v instead of a 9v power supply. Seems like that could mess with the filament voltage. Maybe it’s clamped with a zener? Does 12v work better for a “starved plate” circuit like this? Might change the clipping threshold?

[The Dude]

Found this:

https://www.aguitarforum.com/threads...999-mod.17254/

Maybe useful...... maybe not?

[Mark Hammer]

When tube amp owners desire a less intense tone, they will sometimes switch to a lower-gain preamp tube in the 12A-7 series, such as a 12AY7, 12AT7, or even 12AU7.

[olddawg]

When tube amp owners desire a less intense tone, they will sometimes switch to a lower-gain preamp tube in the 12A-7 series, such as a 12AY7, 12AT7, or even 12AU7.

Yes.. I’m aware of that and plan on swapping few tubes into it. Even a different 12ax7 may be less harsh although these Bugera branded Chinese 12AX7s seem fine in other amps I use. I was more concerned about the recommendations to use a 12v powers supply and it increasing the heater voltage beyond an acceptable limit without modification. Some people have said that the cheap stock wall wort provided does not provide enough current for a 12AU7. This is the first “Starved Plate” circuit I’ve ever messed with. I’m assuming that increasing the power supply voltage might also reduce the clipping threshold? At this cost point I can mess with it all I want I guess, lol.

[The Dude]

You can measure it to be sure, but I'll bet they're running the filaments off the 9V supply anyway, so I don't see why a 12V supply would be a problem. You may want to check to see if there's a zener at the input, though. You might have to clip it out to actually get 12V crammed in there.

[hrbay]

Find a BitMo kit on the bay, easy to put in if you have any soldering chops, gives you three dissimilar voicings,

[olddawg]

What Dude posted earlier is basically the Bitmo kit.

[g1]

Agree with The Dude about the heaters, check what they are running for stock voltage. Rather than stressing them, they may be starved to begin with, in which case you will be upgrading.