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Old 22nd February 2006, 05:54 PM   #1
gianc is offline gianc  Canada
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Default New Aleph 5, questions

Hi everyone,

Iíve finally completed my Aleph 5, everything seems to be working fine. I have a question concerning a unique attribute of my amplifier. The transformers, one for each channel, are rated as a 46 volt center tap, 750 va 240 volts. So connected to a 120 volt source I get 23 volts, which is a bit low for an Aleph 5. The voltage is + and - 33 after the rectifiers, and 29 .5 volts after a CRC power supply arrangement. (each channel has 100,000 uf supply). Currently all component values are as per the schematic. My question is should some of the resistor values be modified from the standard values for the lower rail voltage? Also, is it OK to have the grounds from the power supplies floating, not connect to the ac input to chassis ground? There is a little less hum connected this way.

The amp sounds great, actually better than I had hoped for. Also, the heatsinks seem to be working great, around 45 degrees once it stabilizes, this has me wondering if the lower voltage transformers were a mistake.( bought cheap as surplus) Would it make sense to purchase a new single transformer of a higher voltage to increase to output power? Say 1 KVA 30 volts.
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Old 22nd February 2006, 07:23 PM   #2
Zen Mod is offline Zen Mod  Serbia
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oh,man-just stop thinking and give us some more pictures!
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Old 22nd February 2006, 11:03 PM   #3
gianc is offline gianc  Canada
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ok, here another pic. I'd post a few more but it seems that I will only be able post one per reply.
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Old 22nd February 2006, 11:15 PM   #4
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gianc

the engineering of your amp is as good as np's

well done

cheers
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Old 22nd February 2006, 11:18 PM   #5
Zen Mod is offline Zen Mod  Serbia
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look and finish are extraordinary.....

some innard pics?

btw-look that you have wrong type of XLR on back?
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Old 22nd February 2006, 11:52 PM   #6
gianc is offline gianc  Canada
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Here is one of the inside, before completion.
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Old 23rd February 2006, 12:30 AM   #7
MikeW is offline MikeW  United States
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Default Ground

Also, is it OK to have the grounds from the power supplies floating, not connect to the ac input to chassis ground? There is a little less hum connected this way.


Use a CL-60 thermistor from star ground to chassis ground.
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