Golden Age Pre 73 Mod

[Alexmc1988]

I have a Golden Age Pre 73 Preamp that I would like to do something different with. I have 4 Seven Circle N72s so I have the Neve sound covered. What I am considering doing is upgrading the input and output transformers, changing all of the transistors to germanium, adding a PAD switch, and a "thick" switch(light low end boost). What I would really like is a Chandler Limited Germanium Pre but that's a lot of money and no where near as fun.

I know how to upgrade the Transformers and I think I can figure out the transistors. How would I make a PAD and Low Boost switch? Where would I need to insert those in the circuit?

Also would changing the transistors to germanium make any difference? The only reason I thought I would do that is because that's what the Chandler uses.

Thanks

 

[mhuss]

Germanium transistors are at least an order of magnitude harder to get right and to keep stable than Silicon ones. They change bias point dramatically with temperature, for example. I don't know for sure, but I suspect these "Germanium" products have one or two Germanium transistors in the signal path, not a case full.

--mark

 

[sr1200]

Why not just get one of PPA's germanium pres, theyre not expensive at all.  Kits I think were 70 euro then get the transformers from Jeff at Classic API... its like a 312 with a germanium opamp built in.  I have a pair of them, sound awesome on guitar and bass (esp distorted guitar).  Send him a message and find out when the next batch is coming out.  You dont need a 500 series rack either, you can use a separate PS and rack mount the board (has separate power IN and audio i/o spots on the board for this purpose.

Edited the price on the kits cause i didnt look before i typed... doh!