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Old 26th August 2009, 12:02 AM   #261
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Quote:
Originally Posted by algg View Post
how should the 2sj74's be soldered to the board?
Check this post and the attached pic: http://www.diyaudio.com/forums/showp...1&postcount=85
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Old 26th August 2009, 06:32 AM   #262
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Quote:
Originally Posted by Peter Daniel View Post
Thanks Peter, I've missed this point.
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Old 27th August 2009, 08:22 AM   #263
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Quote:
Originally Posted by Bill Fuss View Post
With 1.8A bias per side about 180 watts per ch.
do you think that 2 per channel of SK56/200SA http://www.fischerelektronik.de/fisc...l_pdf/A_42.pdf will do the job
I would like to mount them 2 on each side of the stereo box
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Old 27th August 2009, 04:18 PM   #264
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Originally Posted by samoloko View Post
do you think that 2 per channel of SK56/200SA http://www.fischerelektronik.de/fisc...l_pdf/A_42.pdf will do the job
I would like to mount them 2 on each side of the stereo box
I would use the SK157/ 150, two per ch.
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Old 27th August 2009, 06:50 PM   #265
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I tested a single Aleph J channel today and everything works fine.

300VA, 2 x 18V Plitron transformer produces approx 28V unloaded and 26V after connecting to the amp.

Loosely matched SJ74 give approX 35mV offset.

Next thing will be J-X setup.
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Old 28th August 2009, 05:27 AM   #266
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I wasn't actually correct, the DC offset was approx 2mV, I forgot about the offset produced by the generator.

The amp runs hot: the 8x8 heatsink with 1.75 fins was way too small for 2 x 18V transformer.

For AJ-X configuration, front end components (inside white border) should not be installed. I just removed them from test channel and I'm slowly getting ready for an X
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Old 28th August 2009, 12:19 PM   #267
algg is offline algg  United States
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Default Resistor location on board

Hi Peter, thanks for the picture - very helpful! One more quick question. Why is R7 offset on your board - you soldered one leg to a different, unmarked thru-hole? Thanks!
-Alex
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Old 28th August 2009, 01:20 PM   #268
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The R7 footprint allows two resistor sizes: 500mil and 200mil, depending on the type used.
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Old 28th August 2009, 06:26 PM   #269
tms0425 is offline tms0425  United States
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Peter,

What is the size of the thru holes you use for signal, ground, and power wires?

I am thinking of getting some turret terminals to facilitate quick solder/desolder for experimenting on mine.

Thanks,

Tom
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Old 28th August 2009, 07:01 PM   #270
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Those are approx 1.5mm (0.060")
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