Sad news to report. During first period of running in amp, it blew a fuse after about 6 hours of playing and since this is test mule with Antek 3218, I only put in 2.5A fuse (2.5x120V = 300W). No big deal. I changed to 3A fuse and it was playing again for about 1 hour and blew again. Changed to 4A fuse and either I wasn't waiting long enough to drain caps or it just was already on way to Ge-drekland. Went back to front end (FE) and output section (OS) testing, FE was still fine but OS was 50% THD. I changed active parts (817, 385, 139/140) thinking the mosfets were sturdy fellows but still no good. Pulled IRF9510 and put on tester, tested ok so only conclusion was Ge. I swapped 22R back in for R122, plugged 2SA1943 and everything is good again in that channel. Has to be 2N1099 slowly turned itself into a jumper wire. Id was set at 1A but after it went bad, on the bench supply, it was pulling 2A (limiter) on both rails.
I will take this opportunity to test 2N277 (Delco) as I found datasheet which is different spec from the Motorola 2N277 and looks like it might survive.
Also found perfect fit mica sheet mica sheet for 2N1099
I will take this opportunity to test 2N277 (Delco) as I found datasheet which is different spec from the Motorola 2N277 and looks like it might survive.
Also found perfect fit mica sheet mica sheet for 2N1099
Stephen,
Really sorry you had a 2n1099 fail on you.
Thanks for posting the datasheets. It's interesting that the Delco gives a max junction-to-case thermal resistance of 0.8C/W while the Motorola one is given as max 0.5C/W. And it seems the Motorola one gives a higher max junction operating temp as well.
Dennis
Really sorry you had a 2n1099 fail on you.
Thanks for posting the datasheets. It's interesting that the Delco gives a max junction-to-case thermal resistance of 0.8C/W while the Motorola one is given as max 0.5C/W. And it seems the Motorola one gives a higher max junction operating temp as well.
Dennis
Dennis
Looks fantastic !!!!
which is ( NFB) nonexistent, but who cares - when you write is as that, it just sounds Posh Just noticed something: In post #411 by myleftear, is it possible the Cinemag transformer is on backward?
https://www.diyaudio.com/community/threads/old-soul.370744/page-21#post-6914960
The holes for Pins 2-5 for cinemag goes are near the edge of the pcbs and in the case of the transfomers I have,
those pins are on the side with the red letter labeling.
https://www.diyaudio.com/community/threads/old-soul.370744/page-21#post-6914960
The holes for Pins 2-5 for cinemag goes are near the edge of the pcbs and in the case of the transfomers I have,
those pins are on the side with the red letter labeling.