I changed the grounding schema at my M2 and no change at all..Now I am in doubt thats even a GND problem! Maybe some interference whit toroids...???
I attached the pictures. As you can see the signal GND, speakers GND and PSU GND are mated at one point! The yellow wire leads to CL-60..
I attached the pictures. As you can see the signal GND, speakers GND and PSU GND are mated at one point! The yellow wire leads to CL-60..
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The input transformers look to be far enough away from the toroids. I would not think that is the problem. Is there any way to move the PS on one channel more toward the center of the case to just see if it makes a difference? I know it is DC but they are closer to the transformers than I would like. Just for a test you might want to lift the chassis ground to see if it makes a difference. Just temporary mind you.
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The PSU is clear of any special artifacts. I get around 18mV of ripple on oscilloscope.
I removed the bypass caps at the end and noticed the amp sound better but the hum is still present on one channel a little bit more than on other. I also noticed when I powerd the amp on one of the toroids did hum for 1 minute or so then it settled but its the same hum I hear in spekaers...
I chased a hum on my first FW build on one channel. Never did find it. Hums can be frustrating but there is an answer somewhere. I replaced the Aleph 30 boards with something else but the hum was never obtrusive while listening to music,the reason I did not spend a lot of time digging into my problem channel board. You may want to try a shield for the input transformers. It is not hard to improvise and make one.
You may want to swap the transformer wires from one channel to the other and see what happens.
DIYspaceW,
can you show more traces of the hum signal?
Maybe also taken from the output of the Edcor or at C2 or at C3 or at the gates?
Thx
can you show more traces of the hum signal?
Maybe also taken from the output of the Edcor or at C2 or at C3 or at the gates?
Thx
Yes since you said the same transformer that hummed on startup is the channel that hums now. I actually do not believe it is the cause but..... maybe worth a try.
Would there be any problem with using a 2200uf cap at C3 in place of the 3300uf as I have plenty of the 2200uf ?
I checked the C3 and no problem there!
I will rearrange the caps to the middle and move the hole plate to middle!
The only difference from left and right side is that the caps on right side (where is more hum) are 1cm
more back than left side...Maybe this is the problem!
I will rearrange the caps to the middle and move the hole plate to middle!
The only difference from left and right side is that the caps on right side (where is more hum) are 1cm
more back than left side...Maybe this is the problem!
Try to keep away those (power) wire, caps etc. from the RCA terminal. That can cause a lot of funny noise, buzz etc.
I do not say 100% that is your problem just to make sure.... 🙂
Do get it this right, a scope trace taken from C3 looks clean while on the output you see ripple? I hadn't expected that... interesting.
Have a look at post #995. I found that the secondary output needs to be furthest away from the M2 input. Rotate your toroids 180* and/or move them as far away as possible.
I will check again tomorrow. I managed to rearrange the whole thing and need to rewire it...