Hi Bonsai,I think that you need to replace this obsolute upc 1237 i.c with discret transistors in the near future.😉
You can buy UPC1237 here:-
https://www.cricklewoodelectronics....MIt-mT_orI9wIVV-vtCh3ddg6AEAQYAyABEgJgMPD_BwE
They will ship internationally as well.
🙂
https://www.cricklewoodelectronics....MIt-mT_orI9wIVV-vtCh3ddg6AEAQYAyABEgJgMPD_BwE
They will ship internationally as well.
🙂
I think I found a bug in the upc1237 chip. Try powering it up with a fault, it will cycle once. I have an original renesas part and a UTC both do the same.
Good day, Bonsai!
thank your for your reply.
Could you privide the rough measurements of the board? Just the width and the length.
Regards,
Ed
Bonsai, does your protection board require a linear power supply to work with an amplifier? Would SMPS-powered designs not be feasible (no accessible secondary AC)?
This board might be a good addition to Fender Rhodes Suitcase Piano power amp modules. The Suitcase amps use dual 40W or 50W amps for stereo tremolo. The older 40W models use Ge power transistors and have no speaker protection. I have seen photos of cases where catastrophic output shorts really burned up the speakers. And the value of Rhodes electric pianos has really gone up lately, so protection would be cost-effective.
Morning Andrew!
I Pmed you the board came in immaculately in short time.
I garthered all the parts needed for the L.S.protection board.
Left is the optocoupler VOM1271/TLP191. Cannot find it in stock anywhere within reasonable time. Can you suggest a suitable replacement maybe?
Is it safe to try Ebay?
Is TLP3906, 3910 a candidate?
Hope you have some hints for me...
Ed
I Pmed you the board came in immaculately in short time.
I garthered all the parts needed for the L.S.protection board.
Left is the optocoupler VOM1271/TLP191. Cannot find it in stock anywhere within reasonable time. Can you suggest a suitable replacement maybe?
Is it safe to try Ebay?
Is TLP3906, 3910 a candidate?
Hope you have some hints for me...
Ed
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Hello von Ah
Apolgies I only saw this now. The speaker protection board needs a line frequency source in order to function correctly. When it senses mains power has been removed, it disconnects the speakers within a few 100’s of milluseconds.
No worries. Thanks!
For another perspective on my question, regarding your block diagram of connecting the protection board in an amplifier:
Could the AC sense on the board come from the AC mains inlet when using an SMPS instead of a linear power supply? If the transformer and rectifier are replaced by an SMPS, would the AC sense still work? See attached markup (mains neutral or live connected to AC sense).
I appreciate your help.
For another perspective on my question, regarding your block diagram of connecting the protection board in an amplifier:
Could the AC sense on the board come from the AC mains inlet when using an SMPS instead of a linear power supply? If the transformer and rectifier are replaced by an SMPS, would the AC sense still work? See attached markup (mains neutral or live connected to AC sense).
I appreciate your help.
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I would not do that on safety reasons. You really want to be completely isolated from the mains side. It only takes a fault and you have a life threatening situation.
Excellent point! Thank you. Safety first.
Perhaps a very small transformer would fit between mains and AC sense, but that’s sort of defeating the simplicity of using an SMPS for the amp…
Perhaps a very small transformer would fit between mains and AC sense, but that’s sort of defeating the simplicity of using an SMPS for the amp…
This is exactly what I did in my AEM6000, with a different upc1237 board.
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Thanks, Jaques! That is a wonderfully laid-out build!
I‘ve seen your praise for SuzyJ’s amp design. How does it compare to your Alpha-Nirvana?