Aleph 2/4 Power Supply Question - diyAudio
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Old 3rd September 2006, 11:07 PM   #1
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Default Aleph 2/4 Power Supply Question

Hi.
I'm going to build Aleph 2 (or 4, don't know for sure yet). I first planned to go into another project and bought 2 nice 750VA Plitron transformers fot it. The problem is that they're rated at 40V AC, so that would be almost +/- 56V DC after rectifier, while Alephs (according to Serv. Man.) are supposed to be run with approx. +/- 48V DC. Can I use them without any changes in circuit (with larger heatsinks, of course) or I should change some values?
Thanks.
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Old 4th September 2006, 02:57 AM   #2
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+-56v you can build aleph1.2.

if you insist to build aleph 2, i think you can refer to half front-end of aleph1.2 and another half back-end of aleph 2.

if you dont want to change aleph 2 circuit, reconsider dissipation of R13 and R17.
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Old 4th September 2006, 03:48 AM   #3
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You could use a C-R-C filter on the power supply and drop the voltage. It would kill two birds with one stone: Lower the rail voltage and quiet the rails.
Within limits, you can run the Aleph circuits at higher voltages as long as you increase the heat sinking. I'm not sure I'd push it as far as 56V without checking the circuit over to see if other things could be optomized for the new rail.
Decide which circuit you're building before you go any further.

Grey
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Old 4th September 2006, 04:37 AM   #4
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As Grey points out a slightly higher voltage can be used to advantage by appointing a CRC filter or eve CRCRC with some CL 60 thermisters. are high wattage reisters -should do it.

The benefit of burning off a few volts is vastly reduced ripple and a quieter amp.

If you have time doodle with PS11 designer to model some ball park figures.

macka
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Old 4th September 2006, 09:28 AM   #5
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Hi guys! Thanx for replies.
Actually I was thinking of using some kind of C-R-C filter to lower the output voltage, but I couldn't find any really useful software to model it.
2macka:
What is PS11? Searched in Altavista and Yahoo - found nothing.
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Old 4th September 2006, 10:13 AM   #6
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Default psu simulation

Try the psu designer fromDuncan Amps Have fun
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Old 4th September 2006, 01:19 PM   #7
jeapel is offline jeapel  Canada
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hi

40 x 1.41 =56

but it s for no load volt

with load you will drop to ~ 51 to 52

and with CLC or CRC you will drop to maybe 48 to 50 not to bad

just do a test with big resistor load before built your amp

bye
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Old 4th September 2006, 08:31 PM   #8
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Thanks again for the replies.
2jasonlky:
thanks for the link - this programm is really something)
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Old 5th September 2006, 09:21 AM   #9
johndiy is offline johndiy  Greece
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i am glad you like it

john
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