Roland AF-100 BeeBaa Trannies.

[Royal Analog]

Roland AF-100 BeeBaa Trannies.

Hey guys! First post here.  I run a small pedal company called Royal Analog in South Africa!

Looking to make my spin on the beebaa, I see that the original transistors are hard to come by and I have a good selection of NPN BC107, 108 and 109's here in South africa.

What would these sound like? Has anyone tried? Also does anyone have any other recommendations?

[andy-h-h]

Low gain works well - out of that selection I'd try the 107s     I've built a stripped down version using some Russian KT315 transistors and it sounds massive.   

[Mark Hammer]

Nothing particularly distinctive about 2SC828s.  They're basically what you use instead of a 2N3904 if you're in Japan.

[duck_arse]

hFE of 65 ~ 700? sounds like an unbatched BC108 or 9 to me.

and welcome to the forum.

[R.G.]

Mark's right - nothing special about the 828. Just a medium to high gain NPN. Most NPNs will do something nearly correct in there.

2N3904, some of the BC types, etc. will all work.

And remember Keen's Second Law: when in doubt, whip in a 2N5088. 

[iainpunk]

i had a bee baa clone on my breadboard for quite a while, i was using 2n2222 trannies in reverse (swapping the C and E pins) and is sounded quite close to the demo's i found online maybe a little bit less gain, but the character was certainly there. the magic of this circuit is in its design, not in any magic transistors, as is with most boss designs (bar the TR808 noise transistor which were selected for their good sounding avalanche noise).

cheers

[aion]

I tested some NOS 2SC828-GRs when doing my Bee Baa and the hFE was all in the 260-280 range, which is almost identical to 2N5088 (250-350) but higher than 2N3904 (150-200). I didn't test the transistors from an original, but this is the next best thing I guess.

Not to imply that a specific hFE is crucial in this application, but just to reinforce that the transistors in the original definitely were not low gain, despite being made in the early '70s when transistor gains tended to be on the lower side.