[sdiy] Oh! I forgot to tell y'all, they did get the MS-20 oscillating in a good audio range...

[lanterma at ece.gatech.edu]

...and what many people suspected was true - using the right  
transistors in the thyristor really *did* matter. They said the main  
player was the PNP - when they swapped that out, the range got better,  
and then swapping in the correct NPN helped "clean it up."

Ack Electronics had NTE equivalents of the original Japanese  
transistors. They had two of the PNPs left and one of the NPNs left.  
And I mean that - I bought out their entire stock. ;)

At some point I need to pull out some datasheets and figure out what  
some good readily available substitutions would be. The 2N3906 and  
2N3904 didn't cut it.

- Aaron