I agree, the McMillans nay not be the culpret, but their solder joint could be? It seems it's a component that destroys cmrr???
flg said:
McMillans are installed, so the schematic is slightly different from the original circuit I showed in previous post. First, I resoldered the parts around the CCS but this did not solve the problem. Next, I'll try installing C102 C105. I will post the results later.
Hi,
yes C102 is the one I meant. Don´t forget there are two of them......
Start with something small like 1n or 1n5.
William
yes C102 is the one I meant. Don´t forget there are two of them......
Start with something small like 1n or 1n5.
William
wuffwaff said:
Here comes a short update of my ongoing chase for the hum in my aleph-x:
1) I inserted C102 and C105 as recommended, but used 10nF instead of the recommended 1nf, since 10nF was the smallest value I had on hand-> no change, same amount of hum
2) Replaced Q3& Q4-> no change, same amount of hum
3) Resoldered all small components around Q3-> around 40% reduction in hum judged by measuring output with scope, amplitude of oscillation is now around 10mV
I also noticed that hum level goes down as amplifier warms up.
Good news is I REALLY like the sound of my aleph-xs the longer I am listening!
Hi,
that´s good news. So I would clean the circuit board and do some more soldering, then clean it again.
William
P.S. don´t forget to remove the caps if they are not necessary!
that´s good news. So I would clean the circuit board and do some more soldering, then clean it again.
William
P.S. don´t forget to remove the caps if they are not necessary!
brif update on my chase of the hum
Hi All,
in my attempts to chase the hum out of one of my monoblocks I think I solved the problem- kind of.
After all my fruitless attempts I finally turned my attention to the input section and I exchanged the LTPs (Q5&Q7). The result is a reduction of the hum to a very low level. On my 96 db efficient speakers you can only hear it within 1m from the speaker. Funny thing is when I look at the output with my scope, I now see almost the identical amount of hum on both sides, i.e. the - side that had before been absolutley silent now has the same amount of noise as the + side. (both sides now look like the lower trace in the picture of my post #123). I guess the result is that the X-configuration now rejects the common noise quite efficiently....
Hi All,
in my attempts to chase the hum out of one of my monoblocks I think I solved the problem- kind of.
After all my fruitless attempts I finally turned my attention to the input section and I exchanged the LTPs (Q5&Q7). The result is a reduction of the hum to a very low level. On my 96 db efficient speakers you can only hear it within 1m from the speaker. Funny thing is when I look at the output with my scope, I now see almost the identical amount of hum on both sides, i.e. the - side that had before been absolutley silent now has the same amount of noise as the + side. (both sides now look like the lower trace in the picture of my post #123). I guess the result is that the X-configuration now rejects the common noise quite efficiently....
Zen Mod said:locall time - 2320
this is Zen :
(again-be happy ,all of you)
how cute, Zen Mod
looks like a father and child image
http://www.diyaudio.com/forums/attachment.php?s=&postid=1094627&stamp=1167603488
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