[sdiy] Vintage transistor ID's? !!help!!

Steve Maietta srmaietta at yahoo.com
Tue Jun 5 17:02:00 CEST 2012

Hey all, I am leading a few of my students on the path of reverse engineering and cloning a vintage Electro-Harmonix guitar amplifier. (A Mike Matthews Freedom Amp)  

We're moving right along but are stumped with the ID and finding suitable replacement of a few old, black blob transistors..

In the preamp section:

In the power amp section:

These next are big TO3 package, heatsinked. NPN/PNP pair i'm assuming..

If anyone could help it would be great!!!!    
Are these PNP/NPN and what would be a current replacement?  wev'e got one week left!

thanks a ton!

and yes I plan on sharing all the info and drawings when we're done..

More information about the Synth-diy mailing list