Oldsansui441
Super Member
This is very helpful! Thanks a lot for looking. So I could use a Panasonic FM low ESR 33µF/25v for that.
Your very welcome, yes they would be a great choice or Nichicon UPW-UPM.
This is very helpful! Thanks a lot for looking. So I could use a Panasonic FM low ESR 33µF/25v for that.
Looks like Reichelt.de have the 2SA1186 and 2SC2837, James.
The 2SC2837 (pdf datasheet) has fT of 70MHz and Cob of just 60pF, instead of 30MHz and 400pF, respectively, for the NJW0302G/NJW0281G.
The 2SA1186 (pdf datasheet) has 60MHz and Cob of 110pF, still lower Cob than the NJW0302G/NJW0281G.
Digikey.at also have them
https://www.digikey.at/products/de?keywords=2sa1186
https://www.digikey.at/products/de?keywords=2sc2837
Cheers
[edit] - If original outputs are 2SC2706 (fT 90MHz, Cob 130pF) and 2SA1146 (70MHz, Cob 220pF), these are extremely fast devices...
Sounds like you have been very busy, yes it would be a pity to have to wait on the relays for 16 weeks preventing your build. Looks like you are going to be doing just about everything in this very lucky amplifier.
Are you going to be replacing the outputs just as a preventative measure or are you going to use the originals, l think you stated in an earlier post that the originals were ok?
Sounds like you have been very busy, yes it would be a pity to have to wait on the relays for 16 weeks preventing your build. Looks like you are going to be doing just about everything in this very lucky amplifier.
Are you going to be replacing the outputs just as a preventative measure or are you going to use the originals, l think you stated in an earlier post that the originals were ok?
James, if you are looking for components take a look here too : https://www.taydaelectronics.com/ It is cheap , the wares are genuine ( I bought a lot of stuffs) and ship via Dhl.de Ciao
I am your faithful follower and pupil CiaoThanks BG! I always enjoy your help and comments. I hope that you stick around during the thread also. I'll check them out today.
Cheers,
James
My plan at the moment is to go step by step through the entire power supply and check everything. I won't replace anything except the caps (*!) but will check/test everything that I can and do a complete re-flow/resolder of the entire amp. In the background I'll continue to research the parts and substitutes for the entire amp and do a series of purchases to have parts on hand for anything that may be needed. All of the leftover/unneeded parts will become a welcome addition to my general benchstock.
Btw, I hope that you stick around during this adventure. Having someone here that has had their hands on an M-70 is a big help. Plus I just like your and Karl & Zaibatsu's posts, as well as the other members that have stopped by with moral support.
Probably just because you meant 1SS821S82 = BAV-21. Funny, I can't find the reference thread(s) again. I'll keep looking and edit it in when found.
Acetone will remove text from even genuine devices, personally I wouldn't use it as a "general solvent", rather best left as a specific choice for DSBG and a few other things (it is however safe for the printing on Yamaha PCBs, even though it's been debated here before, I think everyone who has used it extensively agrees). Isopropyl is a better choice for general use, and for dissolving that old white paste, I've found household olive oil can help break it down gently before using your solvent of choice. Anyway, I don't think losing the text to acetone classifies the devices as fake.
I think it's hard to comment on whether the devices are genuine just by looking at them though, I've definitely seen less-than-perfect printing on genuine devices before. I suppose if you are suspicious of fakes it might be safest to replace/sub all the drivers and outputs.
The other point I wanted to add is - some of the high speed output device recommendations in this thread are LAPT transistors (parallel devices within single device), I'm not sure if that's appropriate if the factory-spec devices weren't also LAPT. Non-composite ("single"?) transistors these days are usually slower than what was available back in the day, it's just a sacrifice you have to make if substituting - particularly for drivers and outputs. I think the 0281G / 0302G you suggested will work fine, and better than the currently installed subs anyway.
It's probably more important to make sure you sub the drivers appropriately, since the A913 / C1913 devices are 120MHz
http://www.svntc.com/TPDF/1335.pdf
http://www.svntc.com/TPDF/2019.pdf
The Toshiba A1837 / C4793 might be a decent sub @ 70 / 100MHz (slightly higher CoB too, but not bad)
https://www.laro.com.pl/pdf/2sa1837.pdf
https://www.mouser.com/ds/2/408/toshiba_2SC4793-1209408.pdf
Bdent still had them last I checked (OMGCat and I got some recently), but the pair are NLA at mouser. I'd pick those over the MJE150xx driver sub options, if you can find them.
Probably just because you meant 1SS82