I think your best bet is to replace those with newer mosfets which have much better specs anyway. You should replace them on both channels. It seems those mosfets are a weakpoint in that design.
Otherwise try here Alta Vista Audio Home Page
Otherwise try here Alta Vista Audio Home Page
I have only 9 pairs in stock. No problem selling 2 pairs. I'm quite certain they can replace the 120V version directly.
Price is US$16.50 each. This is my cost when I bought them in the early 90s. Mosfets were pretty expensive then.
Shipping is about US$8-10 (USPS 1st Class Air Mail) in Carton Box (8"x6"x4").
Do you happen to have the SA12 schematic? I always thought they used 2SK135 and 2SJ50 Hitachi Mosfets. I may be mistaken.
Price is US$16.50 each. This is my cost when I bought them in the early 90s. Mosfets were pretty expensive then.
Shipping is about US$8-10 (USPS 1st Class Air Mail) in Carton Box (8"x6"x4").
Do you happen to have the SA12 schematic? I always thought they used 2SK135 and 2SJ50 Hitachi Mosfets. I may be mistaken.
I don't have the schematic I'm afraid, would certainly be useful though. I think you're right, some did use the 2SK135s and 2SJ50s, others used the ones that are in mine.
Price sounds fine to me, thanks. Message me direct with payment details please, and I'll send my address.
Price sounds fine to me, thanks. Message me direct with payment details please, and I'll send my address.
I think you're right, some did use the 2SK135s and 2SJ50s, others used the ones that are in mine..
The SA12 used the RCA (then Harris) RFM12N10 & RFM12N10 (120V 10A TO3) and the Hitachi 2SK398 & 2SJ112 and finally the International Rectifier IRF130 & IRF9130(100V 14A/11A). All devices are vertical MOSFETs.
The Hitachi 2SK135 and 2SJ50 are lateral MOSFETS and not usable in the SA12 without modifying the design.
The NMOS and PMOS pairs must be closely matched
This thread has the schematics of the SA100 which is similar to SA12
http://www.diyaudio.com/forums/solid-state/54491-counerpoint-sa100-200-power-amp-scheme.html
You should also check out this thread
http://www.diyaudio.com/forums/solid-state/188029-counterpoint-sa12-whats-smell.html
http://www.diyaudio.com/forums/solid-state/54491-counerpoint-sa100-200-power-amp-scheme.html
You should also check out this thread
http://www.diyaudio.com/forums/solid-state/188029-counterpoint-sa12-whats-smell.html
RCA (then Harris) RFM12N10 & RFM12N10 (TO3)
Ahh, happy days.
Not the same numbers, better duo actually, but neither are yours. (12A,100V)
Attachments
Not sure what you mean, jacco.Ahh, happy days.
Not the same numbers, better duo actually, but neither are yours. (12A,100V)
The part numbers I quoted - RFM12N10 & RFM12N10 - are taken from the production inventory list. The parts you show are the TO220(?) packaged version - the difference is RFM versus RFP.
It is easy enough to transpose the numbers - so I went back to the archives and checked!
This thread has the schematics of the SA100 which is similar to SA12
http://www.diyaudio.com/forums/solid-state/54491-counerpoint-sa100-200-power-amp-scheme.html
The SA100 and SA12 output stage is very similar. As in a late production SA12 will be identical to the SA100 but the main board is very different. The SA100 used the main board from the SA20/220.
So the schematic linked to is useful for rebuilding the output stage which is probably all that you need as the preceding circuitry is AC coupled.
Not sure what you mean
Mea culpa, i enjoy riddle joking.
I'm numbers challenged, very pretty sure that the numbers Counterpoint used were : RFM10N12 + RFM12P10.
So i checked too.
Attachments
Here's another thread dealing discussing SA12 output stage repair ... should be of interest.
http://www.diyaudio.com/forums/solid-state/188029-counterpoint-sa12-whats-smell.html
http://www.diyaudio.com/forums/solid-state/188029-counterpoint-sa12-whats-smell.html
Mea culpa, i enjoy riddle joking.
I'm numbers challenged, very pretty sure that the numbers Counterpoint used were : RFM10N12 + RFM12P10.
So i checked too.
Thank you for clarifying that. That makes another 'pair' used in the SA12. Mostly historical interest as the RCA/Harris devices are all long gone.
Mea culpa, i enjoy riddle joking.
I'm numbers challenged, very pretty sure that the numbers Counterpoint used were : RFM10N12 + RFM12P10.
So i checked too.
thank you schematic..
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