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Old 15th November 2006, 05:16 PM   #1
t3447ml is offline t3447ml  United States
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Default New build of Aleph X amplifier

For your consideration, my Aleph X mono blocks built to G. Rollins original design, 15V rails, 4A total bias, 4IRFP044 devices per channel. I would like to thank Grey Rollins for the design, Nelson Pass for the concept and Carondimonio (Bruno) for the boards.
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Old 15th November 2006, 05:17 PM   #2
t3447ml is offline t3447ml  United States
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Front Panel
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Old 15th November 2006, 05:22 PM   #3
hc167 is offline hc167  United States
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look nice, did you make your own chassis or you purchase somehwere else? and where did you purchase it?
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Old 15th November 2006, 05:23 PM   #4
t3447ml is offline t3447ml  United States
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Rear Panel
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Old 15th November 2006, 05:51 PM   #5
moe29 is offline moe29  United States
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does it run cool enough? heat sinks look a bit small.

The build quality looks excellent though
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Old 15th November 2006, 07:17 PM   #6
CJ900RR is offline CJ900RR  Sweden
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Nice looking

What is the power in watt in 8 and 4 omhs from the original schematic?
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Old 17th November 2006, 01:10 PM   #7
t3447ml is offline t3447ml  United States
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The chassis is a Bud 17x12x3 from Digi Key. The sides have been cut off to mount the heat sinks.

The output power, when calculated using wuffwaff's AXE 1.2 spreadsheet, at 4amps bias into 8 ohms is 42 watts and into 4 ohms is 26 watts.

Moe29 you are correct this unit does run too hot. After about 1 hour I can still hold my hand on the heatsinks, after another half hour the heatsinks are too hot to touch.

The amplifiers are driving back loaded Fostex 108EZ horns rated at 24 watts. At my listening levels the volume control on my Aleph P1.7 64 step relay attenuator is set about step 25.

My next step will be to rework the unit to 2.5 amps bias, again from the spreadsheet this comes out to 21 watts into 8 ohms. This should cut the power dissipation for each channel from 148 to 92 watts.
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Old 17th November 2006, 01:49 PM   #8
hc167 is offline hc167  United States
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t3447ml:

do you mind to give me the part number of the chassis from digikey? thanks a lot.
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Old 17th November 2006, 02:00 PM   #9
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Hi t3447ml,

I built an Aleph30 earlier this year that consumes 100 watts of power per channel. It has one 151x350mm heatsink per channel. After about 2 hours the heatsinks still pass the 5 second touch test. I've run the amp for as long as 6 hours on a warm summer day and the amp still passed the touch test.

My 1st Aleph Amp

You may need larger heatsinks even with the reduced power.

Something to consider.

-David
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Old 17th November 2006, 02:18 PM   #10
t3447ml is offline t3447ml  United States
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hc 167, the Digi Key PN# for the chassis is 377-1025ND
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