MP20A Help (DAM Super Bee)

[Kinski]

Hey, do you guys know the pinout for the russian MP20A?

Sadly, I can't get the DAM Super Bee, as simple as it is, to work. Its basically is acting as a clean volume control that barely reaches unity. I always have terrible luck with germanium fuzzes. I've only ever gotten two to work, DAM Drag'n'fly and AnalogMan Sunface.

Is this the correct pinout?

[inefficiency]

http://transistor-spravochnik.ru/description/mp20a/46590

[Kinski]

Thanks!

Got it working. Pinouts were fine. I was just screwing up the + - stuff. I gotta read the new post about negative voltage, etc. Gonna build a voltage converter anyway to power it with a standard 9v supply.

Perhaps I'll mention that this is certainly one of the best fuzzes Ive ever built, and I've built a ton!

I got a pack of 60 MP20A transistors off ebay the other day. I've got no real way to test them, so I just sat down and started swapping them out and adjusting the trimmer by ear. Most of them sounded damn good, but I found one that was just far above the rest. Not as high gain as some of the others but still plenty on tap. No crackly decay, and the gain pot is useful through the entire sweep, which is usually not the case with a lot of fuzz circuits. Extremely dynamic and really sings even at lower gain settings. This thing was a real surprise. Probably the most "pretty" sounding fuzz i've built.

Strangely, this is my first tonebender variant I have ever built. Gotta build the MKII/III/IV now!



Thanks

[induction]

Kinski wrote

Strangely, this is my first tonebender variant I have ever built. Gotta build the MKII/III/IV now!

The MkI is a variation on the Fuzz Face circuit. The MkII is a whole different beast with an extra (very high) gain stage on the input. I like the MkII a lot, soundwise. Plays nicer with wahs and buffered signals than the MkI as well. Never tried the MkIII or MkIV.

Love to hear a sample of your new build.

[rocket88]

i agree with induction, i find the mkII to be a little smoother then the mkI. i know there's a lot of arguments about it, but i thought the mkI tonebender predated the fuzzface and that the fuzzface was modeled after the mkI tonebender.

also, i love mp20a's, another real winner as far as russian Ge transistors go. plus they're still reasonably priced, but it seems they are starting to go up, like every other good russian Ge transistor.

[induction]

rocket88 wrote

i know there's a lot of arguments about it, but i thought the mkI tonebender predated the fuzzface and that the fuzzface was modeled after the mkI tonebender.

That might be the case. The circuits have nearly identical topologies, but I don't know which one was first.

[rocket88]

true, i'm pretty sure it's a never ending argument. i don't think it matters which one was first, they both sound great and have their own sound/tone. that's why i have both

[Kinski]

Thanks for the info fellas.

I thought this was a MKI, but the MKI supposedly had 3 transistors.

The lineage of the tonbebender is easy to confuse.


According to the DAM website:

In 1965, MKI (3 transistors).
Then in 1966, VOX Tone Bender (2 transistors), which is what the Super Bee is based on, it seems.
Then the 3 transistors came back for the MKII, MKIII, etc.

The whole article can be found here:  http://www.stompboxes.co.uk/History.html

[Heath]

Sola Sound Tone bender MkIII is the fuzz of the gods.