Hi folks.
After a year of collecting parts (not much cash alas!) and 'little by little' piecing this classic together, I finally got to switch on point this morning. All parts are brand new apart from a pair of original output trannies with a mixture of cloth and PVC covered leads.
Driver board is the Dynakits restoration module (same as original). Quad cap is the Dynakits 525V 80/40/30/20 type. Bias caps are Black Gate standard 100uF/100V types. The power transformer is a 240V type from Triode (P-521-S). This vibrates/buzzes quite a bit - quite disappointing as I was led to believe from their website that these are meant to be quiet compared with original items. The mains here in Basingstoke, England, measures around 247V so that should be well within the specs of this power trannie...
I made sure I sure followed the original Dynakit wiring diagram to the letter, so am quite surprised I have hum issues.
I tried plugging just the ST70 in, disconnected the earth wire (I live in the UK), and used a pair of cheating RCAs. There was still a low level buzz coming from the speakers so - alas - the problem rests somewhere inside the amp. The unit seems to bias OK.
Music sounds absolutely stunning through the amp, so I really want to try and get rid of this hum or I'll have to go back to solid(boring)-state - eeek!
I'll post a pic once I've worked out how this is done Yellow_Light_Colorz_PDT_21
All help gratefully received!
- John