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Old 13th January 2005, 08:53 PM   #1
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Default What have I built?

HI all

After much stuffing around , misunderstanding, and generally not knowing what I'm doing,, I've managed to build a version of an Aleph AMP,
It was Intended to be an A5, using some left over parts but most notably as some may have noticed in other threads, some undersized and Fan cooled heatsinks.

In short at the end of the day its spec's are essentially as follows:
Supply Voltage +-36V from 50VCT 50A trafo
PS caps 4 X 80KuF
Reduced bias to keep thermal trips on hetsink adjacent output itf240's -I have 0.36V across 1 ohm resistors attached to irf240's (A5 should be 0.6V accord to schematic)
Total 6 mosfets per channel.
IRF240 case temperature 59deg C stabilized (at last)
offset about 50mV

I think others out there know the math to work out what power output I can expect and I would be greatful for any comment.

Have I built a mini Aleph??

BTW it sounds great! (is being used in a triamp system as a mid -range amp and I have also tried it full range- very nice indeed)


Cheers and thanks in advance
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Old 13th January 2005, 09:18 PM   #2
cowanrg is offline cowanrg  United States
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sounds kinda like an aleph3 maybe? maybe a 30?
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Old 13th January 2005, 09:47 PM   #3
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Did the off-the-cuff calc's, and it looks like you have approx. 20W into 8ohms and 10W into 4 ohms. Your amp's power output is current limited across the impedance range at this point, giving you more or less a MiniA.

If you can find a way to improve your cooling (bigger heatsinks or add a fan, etc.) you could increase the bias. Based on your trafo rating, with increased bias you could upgrade to somewhere between an Aleph3 and 5.

Cheers, Terry.
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