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BA312 replacement

richiem46 said:
I just saw this item on the big auction site. It looks interesting and at $20.00 the price is right. I ordered two of them and when they arrive next week I will install them in a Marantz 2275 I am restoring that has a bad BA312. I will post the results once I receive and install them. Is anyone familiar with this particular device?

Thanks!

View attachment 2655214
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I received these boards and installed them in a Marantz 2275 I am restoring that had a bad BA312. The pins on the board initially would not fit into the holes in the PE01 board. I contacted the seller and he said he had not installed the Boards in any Marantz gearand said he ordered some smaller pins and would send me new boards with the smaller pins.


In the meantime I went back to looking at the PE01 board and was mulling things over. I had a 3/64 in drill bit, too small to chuck in my makita drill (and not a good idea anywat with how sensitive the foil is on Marantz boards.I twisted the bit between my fingers on each board hole widening the open slightly through the foil plus cleaning out any rosin and other stuff that might be causing an issue. I just did the foil side gently and tried to re-fit the chip until....They fit in! Veeeeeery snug fit but they are in and I am attaching a photo. I re-installed the board in the 2275 and turned it on and it is playing beautifully I an very happy to say!


I suggested the seller still pursue making the pins a bit smaller for marantz restorers as I don't think a lot of people will want to go through what I just did to install them.

The good news is that the 2275 plays beautifully, of the three that I restored I think this one sounds the nicest and I have not gotten to the power amp boards yet. Once the seller adjusts the pin size, another option to consider as a replacement for a bad BA312.

PXL_20220909_010107736.jpg
 
TupolevFan said:
hmm interesting project for Easy EDA program for a new adapter module. I could do it. We could try smt variant and normal components variant. For SMT variant we can even use Rhom transistors
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Someone else not on this forum has prototyped and made a replacement BA312 already. It works, and is a drop in. A few have been sold, and rev2 is coming out in a couple weeks.

It precisely matches the original performance and is a drop in replacement with SMT parts.

I will post an update when it is available.
 
Drilling bigger holes is normal, plenty of capacitors with thicker leads you have to do that for.
No biggie.
I have a small manual drill, it doesn't take much.
 
Magnus Back said:
Drilling bigger holes is normal, plenty of capacitors with thicker leads you have to do that for.
No biggie.
I have a small manual drill, it doesn't take much.
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I was looking for my Dad's old hand drill but apparantly it went in the yard sale when I sold our house back in New Jersey...:dunno:
 
I just bought a pair to do a check with an audio analyzer. I did that for the very nice Sparkos upgrade parts and found that they lowered the noise floor. Just curious!

I'll be posting the results on the referred to BA312 thread in post #105

EDIT: I will post here, that post just has the link to the part on eBay. It may take awhile!
 
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rBuckner said:
I just bought a pair to do a check with an audio analyzer. I did that for the very nice Sparkos upgrade parts and found that they lowered the noise floor. Just curious!

I'll be posting the results on the referred to BA312 thread in post #105
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Maybe you could test the ones @bubhardy made as well? Should be same circuit topology.
 
rBuckner said:
Oh wait - I ordered the ones online. If @bubhardy would like to sell/send me some he sure could, and I'll test them. My analyzer is a Panasonic VP-7782A so has a very low noise floor.
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You can test also the one i created. gerber file is attached in my previous posts. I had 2 versions one for smd and another for TO-92
 
bubhardy said:
If you would like some boards, PM me, and maybe we could arrange it?
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Hey Bub, You can buy a $5 KIT that has the three transistors and four resistors that live "inside" the BA312.
I use these on a weekly basis and it takes about five minutes to solder the parts onto the new PCB.
This guy sells these Kits like they are sliced bread!!
I've spent the last 41 years servicing high-end audio and this $5 kit is THE BOMB!!
https://www.ebay.com/itm/115576118354
Warmest regards,
JJ
 
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