Awhile back I had a thread asking opinions on replacing the outputs in a Yamaha amplifier. It used 2SA1169 and 2SC2773 and it was concluded that MJL1302 and MJL3281 would make a good replacement despite having less overall surface area in contact with the heatsink. The MJL devices having higher dissipation, voltage and current capabilities. Well that Yamaha (R-1000) used one pair per channel and it’s been running every day for 3/4 of a year without issue.
Well I’m in the same boat, but this amp uses even lower power capable outputs, so I don’t see why this wouldn’t work, though there are many more packed onto the heatsink, and it’s a much nicer amp.
It’s a Kyrocera A-910 and each channel of the amp uses three 2SA1215 and three 2SC2921. Unfortunately the outputs are not too healthy.
One had the front of the case blown off of it. Both channels each have one NPN and one PNP that are good, the rest are either shorted, open, or measure as a diode on a Peak Atlas DCA75. The plan was to buy enough to replace all 12 from B+D enterprises, but when I went to purchase 12 of each I found that they only have
2 of one and 5 of the other. So sadly not an option. So my thoughts are to drill and tap new holes in the heatsink for the MJL devices, thoughts?
Secondly, it looks like they’re being driven by a pair mosfets, 2SK214 and 2SJ77. Is there anything that will work here? Or if they die I basically have a very heavy paperweight? It would be sad for something so nice and powerful to be taken down by tiny TO-220 devices. I measured once channel and they measure okay, but haven’t done the other. Thought I should plan just in case the mosfets in the other channel were taken out when the outputs died.
Dan
Well I’m in the same boat, but this amp uses even lower power capable outputs, so I don’t see why this wouldn’t work, though there are many more packed onto the heatsink, and it’s a much nicer amp.
It’s a Kyrocera A-910 and each channel of the amp uses three 2SA1215 and three 2SC2921. Unfortunately the outputs are not too healthy.
One had the front of the case blown off of it. Both channels each have one NPN and one PNP that are good, the rest are either shorted, open, or measure as a diode on a Peak Atlas DCA75. The plan was to buy enough to replace all 12 from B+D enterprises, but when I went to purchase 12 of each I found that they only have
2 of one and 5 of the other. So sadly not an option. So my thoughts are to drill and tap new holes in the heatsink for the MJL devices, thoughts?
Secondly, it looks like they’re being driven by a pair mosfets, 2SK214 and 2SJ77. Is there anything that will work here? Or if they die I basically have a very heavy paperweight? It would be sad for something so nice and powerful to be taken down by tiny TO-220 devices. I measured once channel and they measure okay, but haven’t done the other. Thought I should plan just in case the mosfets in the other channel were taken out when the outputs died.
Dan
The 2SK214/2SJ77 are good lateral mosfets drivers.
MJL1302 and MJL3281 are good transistors. Powerful.
But those big 2SA1215/2SC2921 are even better.
Anyhow you could of course use those TO-264. No problem.
You want some Lateral MOSFETs.
Best are the EXICON power Lateral MOSFETs.
http://www.exicon.info/products.php
https://www.profusionplc.com/type/lateral-mosfet
They come in TO-3, TO-264 and TO-247
MJL1302 and MJL3281 are good transistors. Powerful.
But those big 2SA1215/2SC2921 are even better.
Anyhow you could of course use those TO-264. No problem.
You want some Lateral MOSFETs.
Best are the EXICON power Lateral MOSFETs.
http://www.exicon.info/products.php
https://www.profusionplc.com/type/lateral-mosfet
They come in TO-3, TO-264 and TO-247
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I would figure the 2SA1215 and 2SC2921 would be better suited for the amp since that’s what they originally used, but unless I want to roll the dice with eBay that isn’t an option. Hence the thought of using the TO-264.
Out of curiosity, what makes the 2SA1215 and 2SC2921 better than the MJL1302 and MJL3281?
As for the mosfets, I’m guessing nothing in a TO-220 case? Wonder if I could get the TO-247 to fit, that would be the closest I guess. Still might be physically too large though.
Dan
Out of curiosity, what makes the 2SA1215 and 2SC2921 better than the MJL1302 and MJL3281?
As for the mosfets, I’m guessing nothing in a TO-220 case? Wonder if I could get the TO-247 to fit, that would be the closest I guess. Still might be physically too large though.
Dan
2SA1215 and 2SC2921 are powerful and can take a lot.
I maybe cannot see why they are better.
Maybe because the size. It is just a feeling I have.
About Lateral MOSFETs.
You can go for 2SK1058/SJ162.
https://www.renesas.com/us/en
They are TO-3P. Plastic TO-3
I maybe cannot see why they are better.
Maybe because the size. It is just a feeling I have.
About Lateral MOSFETs.
You can go for 2SK1058/SJ162.
https://www.renesas.com/us/en
They are TO-3P. Plastic TO-3