Finally I have my first Aleph 2 up and running.....on the bench for now though. Was VERY happy with the results as my offset was only .007 volts! It paid off buying that 75.00 Fluke 8505 61/2 digit bench meter on E-bay. This allowed very precise matching of all the mosfets at home. I guess my only gripe so far is the slight noise in the output from not enough power supply filtration. I am leaving enough room in my chassis to deal with this though. My filtration is at 54,000 mfd per rail right now. Perhaps an inductor between caps would clean up things a bit more. I'll post pics later on when I have had everything anodized and assembled....but for now just wanted to get one of them running correctly to verify that it all worked before having it all anodized.
Mark Gulbrandsen
Salt Lake City, UT
P.S. Hey Nelson......Thanks for sharing all this with us!!!!
Mark Gulbrandsen
Salt Lake City, UT
P.S. Hey Nelson......Thanks for sharing all this with us!!!!
incarnated halojoy
Banned
Joined 2002
Banned
Joined 2002
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Joined 2002
And here are my AWSOME BOARD from pass labs.com. Thanks karen. : O ) here is a pic of the boards mounted to the heat sinks im making a stereo block and if all goes well im going to build another stereo block. Curently im thinking about useing the zens for my commputer amplifier.
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Here are a few pics of the operating Aleph 2 on my kitchen table. Will finish the chassis for both now that this one has proven itmnall out for me.
The voltages all check out fine except for .4 volts across the 1 ohm resistors. The heatsinks actually run only moderately hot. So will crank on the bias tommrrow night and hear the results. The transformer is a 780VA AVEMCO that I got surplus for 12 bucks each. Rails are at plus and minus 43 volts and filtration is by two 56000 @ 63 volt caps per rail that cost 10 bucks each. The heatsinks are new and ran about 20.00 each fomr M&M Metals in Texas. Each heatsink is 5 inches square and 6 inches tall.
Can't say enough good about those guys....so cooperative to the small guy like us and all to reasonable pricing.
All wiring is teflon 18 gauge at this point.
Mark
The voltages all check out fine except for .4 volts across the 1 ohm resistors. The heatsinks actually run only moderately hot. So will crank on the bias tommrrow night and hear the results. The transformer is a 780VA AVEMCO that I got surplus for 12 bucks each. Rails are at plus and minus 43 volts and filtration is by two 56000 @ 63 volt caps per rail that cost 10 bucks each. The heatsinks are new and ran about 20.00 each fomr M&M Metals in Texas. Each heatsink is 5 inches square and 6 inches tall.
Can't say enough good about those guys....so cooperative to the small guy like us and all to reasonable pricing.
All wiring is teflon 18 gauge at this point.
Mark
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Mark A. Gulbrandsen said:
Looks like quite the monster monoblock. I like the turrett terminals. I will have to look for some. Where did you get yours?
The pcbs look so small next to the huge heatsinks.. hard to imagine that they are 4"x6"...
How warm do the heatsinks run after they have been on for a few hours?
--
Brian
Hi Brian....
Yea...this has been an ongoing project that I was going to do in a months time off from work. So much for that month. It took longer than that just to get the sinks. Then work got really busy too. Oh well........
Look like the temp is around 60 deg. C right now measured on the device itself with my Tektornix temp probe. Its been on for about 4 hours. These sinks work great! Voltage across the one ohm resistors is about a tenth of a volt low right now though so I am expecting a bit higher temperature when I get it cranked up a to .5. I Am going to raise it to .5 volts as per the drawing and leave it there for a while and do some listening. I'll go higher from there after a few days. Right now it sounds really amazing. I've dug out every old mono Jazz CD I could find and listened all night last night. Good mono isn't so bad either. Am driving the amp with my home brew Aleph L.
Mark
Yea...this has been an ongoing project that I was going to do in a months time off from work. So much for that month. It took longer than that just to get the sinks. Then work got really busy too. Oh well........
Look like the temp is around 60 deg. C right now measured on the device itself with my Tektornix temp probe. Its been on for about 4 hours. These sinks work great! Voltage across the one ohm resistors is about a tenth of a volt low right now though so I am expecting a bit higher temperature when I get it cranked up a to .5. I Am going to raise it to .5 volts as per the drawing and leave it there for a while and do some listening. I'll go higher from there after a few days. Right now it sounds really amazing. I've dug out every old mono Jazz CD I could find and listened all night last night. Good mono isn't so bad either. Am driving the amp with my home brew Aleph L.
Mark
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Hi Nelson,
Thanks for the kind compliment!! Comming from the Master that really means something. I think I'll print that out and frame to hang on the wall above the Alephs. This has been a most interesting project with more time being spent on making the chassis parts than the electronics itself. Also learning how to match the devices was quite interesting as in all my years of building stuff I had never done that before. My next project will most likely be a balanced preamp to go along with the Alephs.
Kindest regards,
Mark
Thanks for the kind compliment!! Comming from the Master that really means something. I think I'll print that out and frame to hang on the wall above the Alephs. This has been a most interesting project with more time being spent on making the chassis parts than the electronics itself. Also learning how to match the devices was quite interesting as in all my years of building stuff I had never done that before. My next project will most likely be a balanced preamp to go along with the Alephs.
Kindest regards,
Mark
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