http://www.arcade-electronics.com/c..._catid=243&sid=7@mDZ21En7rl3Dg-16105447801.9c
Arcade Electronics that SKLIMEK posted has the same thing
but if you want to call the place near me
www.cablesandconnectors.com
they have it too.
Oh, for my Aleph 2's, i used a 280k resistor for r19, and 2k for r21, then put pots across them, 100k and 2k respectively to adjust bias and ac current gain...this way there is always a resistor in the circuit when i put a switch and fixed resistors in...so i can switch bias and ac current gain to a lower level when i want to run the amps at low power
-Matthew K. Olson
Arcade Electronics that SKLIMEK posted has the same thing
but if you want to call the place near me
www.cablesandconnectors.com
they have it too.
Oh, for my Aleph 2's, i used a 280k resistor for r19, and 2k for r21, then put pots across them, 100k and 2k respectively to adjust bias and ac current gain...this way there is always a resistor in the circuit when i put a switch and fixed resistors in...so i can switch bias and ac current gain to a lower level when i want to run the amps at low power
-Matthew K. Olson
Banned
Joined 2002
AC current gain
Matt,
Thanks for the link. And the suggestion - an easy way to adjust bias!
Regarding adjusting DC bias and AC current gain, let's say the target is 3A for your Aleph 2, you'll adjust R19 FIRST, and then R21, UNTIL the meter reads 3A? I'm trying to refresh my memory regarding adjusting AC current gain.
Matt,
Thanks for the link. And the suggestion - an easy way to adjust bias!
Regarding adjusting DC bias and AC current gain, let's say the target is 3A for your Aleph 2, you'll adjust R19 FIRST, and then R21, UNTIL the meter reads 3A? I'm trying to refresh my memory regarding adjusting AC current gain.
heres a pretty good link using a 200k trimpot for bias adjustment that I found trying to get everything straight in my head as well;
http://www.diyaudio.com/forums/showthread.php?s=&threadid=8727&highlight=
the procedure for R21 is alittle more elusive but look here;
http://www.diyaudio.com/forums/showthread.php?s=&threadid=51808&highlight=
Netlist provided a link that takes you to Nelson article on page three for ac bias adj.
also, the WIKI on The AlephX talks about ways of going about it.
I actually went to sleep thinking of R19 and R21 one night trying to sort it all out. How sad is that?
Stan
http://www.diyaudio.com/forums/showthread.php?s=&threadid=8727&highlight=
the procedure for R21 is alittle more elusive but look here;
http://www.diyaudio.com/forums/showthread.php?s=&threadid=51808&highlight=
Netlist provided a link that takes you to Nelson article on page three for ac bias adj.
also, the WIKI on The AlephX talks about ways of going about it.
I actually went to sleep thinking of R19 and R21 one night trying to sort it all out. How sad is that?
Stan
You don't have to do it the way i did. 100k and 1k pots will work fine in place of r19 and r21. I have not tried adjusting r21 yet, so i don't know how much it'll effect bias, though i think bias effects ACIG more than ACIG effects bias. I'd set the bias first, its amazingly stable, then fiddle w/ acig until you're satisfied. I doubt the meter will move much while you are adjusting acig. I could be wrong though...haven't done it yet. Soon maybe this weekend i'll fiddle w/ it. Later!
-Matthew K. Olson
maybe this weekend i'll fiddle w/ it. Later!-Matthew K. Olson
Banned
Joined 2002
Coulomb said:
As far as I have read, the 044 should work better when there are no parallel devices. I listed the IRFP240 for the Aleph30 amp with parallel devices. I am sure that the IRFP244 will work fine for the Mini-Aleph version as well.
As for the caps, use your own judgement, I listed 50v for all kits, as they fit on the board. Lower voltage caps should be fine for lower power setups. (for all of the caps on the boards)
--
Brian
Banned
Joined 2002
The power supply boards arrived today. They are substantially thicker than the gainclone boards. They look quite good. Here is a pic:
I will put up more pictures soon. The amp boards should be here tomorrow, as they shipped a day later.
--
Brian
An externally hosted image should be here but it was not working when we last tested it.
I will put up more pictures soon. The amp boards should be here tomorrow, as they shipped a day later.
--
Brian
Banned
Joined 2002
Here is Brian's SMD board on my 8 x 8 Inch Heat sink's Im starting to worry that my heat sinks might not be enough : O (
An externally hosted image should be here but it was not working when we last tested it.
big enough
Hi,
I built a stereo aleph50 using 4 heatsinks a little bigger than the one in the picture. Mine are about 9 x 9, the reason it became a stereo 50 was because it ran too hot with the rails and idle current at the correct point for an aleph60...
With an ambient of 20c each of the sinks I have is good for about 75w with the fins vertical and a surface temp of 55c, I used 4 devices on each of 4 faces, arranged to make a cube... though I'd could probably have got lower temps using more parts, I just didn't have enough matched.
If all else is equal you should get approx 80% of the cooling performance from each one of the plates you use, so ~60w...is that enough for what you are trying to make?
Stuart
Hi,
I built a stereo aleph50 using 4 heatsinks a little bigger than the one in the picture. Mine are about 9 x 9, the reason it became a stereo 50 was because it ran too hot with the rails and idle current at the correct point for an aleph60...
With an ambient of 20c each of the sinks I have is good for about 75w with the fins vertical and a surface temp of 55c, I used 4 devices on each of 4 faces, arranged to make a cube... though I'd could probably have got lower temps using more parts, I just didn't have enough matched.
If all else is equal you should get approx 80% of the cooling performance from each one of the plates you use, so ~60w...is that enough for what you are trying to make?
Stuart
Banned
Joined 2002
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