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Old 20th May 2010
Lives for gear
mexicola's Avatar

Originally Posted by Jim Williams View Post
Modern Japanese transistors will lower the noise, but THD is high with this design at higher gains.

They can be rewired into trans-amps by cutting the opamp feedback loop and tying that feedback resistor to the inverting transistor emmiter. That will lower preamp noise below that of a mic and will lower THD levels considerably. You can get -129.6 EIN with that preamp if reworked.
Jim, what transistors do you recommend as replacements?
Also, which side of the feedback resistor gets tied to the inverting transistor?

Does anyone else who owns one of these have problems with the master buss signal "leaking" into the aux sends? More so into 1-4 and less so into 5-8 with mine.

It's been a couple years now since I did all the mods (beefing up the psu, recapping with larger electro values, adding wima bypass caps, rechipping with LME's, adding massive amounts of psu decoupling), and I love this board! I've had a couple guest engineers in my studio that were more than pleasantly surprised by the sonics.