Aleph 2/4 Power Supply Question

onewhowaits · 3rd September 2006, 10:07 PM

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.

john-china · 4th September 2006, 01:57 AM

+-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.

GRollins · 4th September 2006, 02:48 AM

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

macka · 4th September 2006, 03:37 AM

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

onewhowaits · 4th September 2006, 08:28 AM

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.

jasonlky · 4th September 2006, 09:13 AM

Try the psu designer fromDuncan Amps Have fun

jeapel · 4th September 2006, 12:19 PM

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

onewhowaits · 4th September 2006, 07:31 PM

Thanks again for the replies.
2jasonlky:
thanks for the link - this programm is really something)

johndiy · 5th September 2006, 08:21 AM

i am glad you like it

john

3rd September 2006, 10:07 PM	#1
onewhowaits diyAudio Member Join Date: Sep 2005	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.

4th September 2006, 01:57 AM	#2
john-china diyAudio Member Join Date: Feb 2001 Location: where fair living	+-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. __________________ Maybe i should not be lazy again

4th September 2006, 09:13 AM	#6
jasonlky diyAudio Member Join Date: Jan 2006 Location: Hot and Humid	psu simulation Try the psu designer fromDuncan Amps Have fun __________________ Seize the day

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4th September 2006, 02:48 AM	#3
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	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

4th September 2006, 03:37 AM	#4
macka diyAudio Member Join Date: Dec 2001 Location: Australia	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

4th September 2006, 08:28 AM	#5
onewhowaits diyAudio Member Join Date: Sep 2005	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.

4th September 2006, 12:19 PM	#7
jeapel diyAudio Member Join Date: Sep 2003 Location: quebec	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

4th September 2006, 07:31 PM	#8
onewhowaits diyAudio Member Join Date: Sep 2005	Thanks again for the replies. 2jasonlky: thanks for the link - this programm is really something)

5th September 2006, 08:21 AM	#9
johndiy Banned Join Date: Aug 2006	i am glad you like it john

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