Blown mje350 and led [REPAIR VID AT END] [resolved]

[Rob Capizzi]

MJE5731A looks discontinued.  Recommend a sub? Think ebay has genuine?

[sl-15]

Nicely done with the mod, thanks for sharing.
I bought some transistors on eBay once for my Foreplay and they crapped out after a month or so. If you do all that work I would spend a few more bucks and order from a reputable seller even if shipping is higher in the end than the parts.
This seems to be the same the only difference that I saw is the Watt rating which is 50 instead of 40: MJE5731AG

https://www.mouser.com/c/?q=MJE5731A

But Paul will know better, in case I am wrong.

[Rob Capizzi]

I really appreciate all the help and knowledge.  I could however benefit from a parts list. I could make one but I don't know the zener diode part. I'd assume there are different ones? Thank you.

[Paul Birkeland]

Good to know. Thank you. can I buy what I need from BH?

We no longer use or stock the 2N2907, so this is probably a better order for Mouser.

[Paul Birkeland]

MJE5731A looks discontinued.  Recommend a sub? Think ebay has genuine?

https://www.mouser.com/ProductDetail/onsemi/MJE5731G?qs=sGAEpiMZZMv4z0HnGdrLjjK%252BdB6HHs0Yogi5zyayRfc%3D
https://www.mouser.com/ProductDetail/Broadcom-Avago/HLMP-6000?qs=jT9z6tsiFNmh%2F1NRKSS5EA%3D%3D
https://www.mouser.com/ProductDetail/Central-Semiconductor/2N2907-PBFREE?qs=u16ybLDytRY%252BTMJ2a8Vx4w%3D%3D
https://www.mouser.com/ProductDetail/Vishay-Semiconductors/1N4761A-TR?qs=8Acm1RElxHLZ6H5eAfHicA%3D%3D

[Rob Capizzi]

Thank you everyone!

[Rob Capizzi]

Ohm question. I have sonus faber concertino and concerto. Thoes are 6ohm. I assume there shouldn't be a problem there hasn't been for over a year. I have to look if the opt is wired 4 or 8. Which is recommended?

[Paul Joppa]

Ohm question. I have sonus faber concertino and concerto. Thoes are 6ohm. I assume there shouldn't be a problem there hasn't been for over a year. I have to look if the opt is wired 4 or 8. Which is recommended?

"Which is recommended?"

I recommend the one that sounds better to you.

:^) Both are reasonable choices from a technical perspective. But they will interact differently with the speakers, and the differences will likely be audible.

[Rob Capizzi]

:^) Both are reasonable choices from a technical perspective. But they will interact differently with the speakers, and the differences will likely be audible.

Ok thought so, thank you.  I've obviously googled it a bunch. I went to 4 ohms on the dynaco vta st120. I like it.

[Rob Capizzi]

Since I'm replacing both 12at7, I'm looking at matched JJ. Any reason not to?

[Paul Birkeland]

https://www.ebay.com/itm/285550720735?hash=item427c2636df:g:F4UAAOSwIwllPxzi&amdata=enc%3AAQAIAAAAwOasRtz9VYGFhb8On%2FTQl6dZNug4HvYW32NWrlSonhQ4eD3PQ1kljn2HQoQv%2Fztl%2Bumsq6ZYtOt255MYIk%2FiBbC30SGbQScHThyQB65ntWm%2B5AmunGgSoNWMWiySJeJuSeXG42hjqPrZ4MQACJQY2U2qCNKLiGSPzL0fhfpqxh%2B8nx4td5%2FohCOvJj4RRm%2FmavGbBX0efLt%2FdBhU%2F75c8afer%2FajUUft0VbEo21U%2B1FFfa9stl9ff9S7LoUZa9027Q%3D%3D%7Ctkp%3ABk9SR-jO1J_5Yg

[Rob Capizzi]

Nice find. Thank you. Bid is in.

[Rob Capizzi]

Once all the new components and tubes are in should I start the amp with a variac and take measurements or just turn it on with fingers crossed?

[Rob Capizzi]

On the mje350
1.emitter
2 collector
3 base
MJE5731g
1 base
2 collector
3 emmiter
So I will install backwards.

[Rob Capizzi]

The MJE5731G I ordered is 350v
There is an mje5731AG that's 375v and available.
Should I have ordered the MJE5731ag ?
https://www.mouser.com/ProductDetail/onsemi/MJE5731AG?qs=R2UZ7gjkEjIIBIrVFKMX3w%3D%3D