Did mount 1T813 today, in place of 2N1099
fired it up, it set itself exactly at same Iq (as previously 2N1099) , did just minor tweak of output offset
same situation for both channels - everything perfect in static state
then connected old crummy Sigene to input, scope to out, no load, just to check does modulation reaching output
first channel OK
second channel - started , and somewhere at half ( of max) thingie just went South - speaker DC protection dissengaged relays, got 48V across 0R11 resistor group ( where I need to see 110mV)
powered it off, logical check - dead mosfet, dead Ge, two 0R22 resistors dead ( there is a reason why there are 2 or 3W jobbies)
was it 1T813 Dud ? most likely ...... and now I'm thinking what and how to test them if I decide to get them in quantity
it seems test with actual load, fastest way of Ge tossed in 1L container of demi water is easiest way to do it
anyway - replaced what's Dodo, checked rest of circuit and fired it up again
this time everything went good, so did tried both channels with load, up to clipping
Aah, you got me!https://www.diyaudio.com/community/threads/old-soul.370744/page-15#post-6850818
Myleftear, did you stop to chat with the pretty people and forgot to cross the finish line? How about some pictures and listening impressions of your Old Soul. You know the rules, no popcorn, no glory ... something like that
Dennis@twitchie: Looking good! I completely forgot about the Toshibas when I last ordered parts. But I suspect I will stick to the germanium.
Do you guys think it's feasible to wire both the mosfet and the Ge part 'off pcb'? This may give a bit more flexibility in the placement of the output devices on the heatsink. It this is ok, is there anything to watch out for (aside from, say, putting the gate resistor on the mosfet when mouting it offboard)?