I followed youre advice on the cabling of the amp and pre-amp, after some search on google and diy audio, i realized that lots of people are putting the pre-amp in a seperate casing, where the volume pot and input selector pot are at closed range of the pcb mounting pads, or direct on it. That is not a luxury i have at the moment.
To limit the external influence on the input cabling and pot wiring i ordered an ftp cable (foiled twisted pair) and soldered these between the input selector pot and the mez-b1, next to that i soldered the same kind of wire between the output of the mez-b1 and the input of the Aleph J, after that i removed all but one of the input cables from the RCA inputs to mez-b1. after that i fired up the amp but despite my effort the hum survived
.. darn. So i gave it a night rest and thought about it, i decided that my next attempt was to rule out all of the extra components that i installed next to the Aleph J, psu and transformer: on/off switch, ntc thermistor block, mez b1 (with own transformer) and ntc thermister to ground.
After decoupling the extra parts, decoupling in my mind means taking them of the power circuit, i fired up the amp which at that moments consisted of the psu v3, transformer and aleph pcb i discovered that the hum survived... again (when does this battle end )
i did one last attempt before writing you guys for advice, i took one channel down but this diddent have any effect either.
so i think this has something to do with, the transformer, monolithic blocks, psu v3 or the aleph J boards.
please help....
p.s. one last piece of information, my transformers hums a ver little bit also.
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you said hum vanished when inputs are grounded ditto on pcb
so , just try to route input wires in that way they're not picking hum
use shielded cable , input connectors must be isolated from chassis
so , just try to route input wires in that way they're not picking hum
use shielded cable , input connectors must be isolated from chassis
who cares for music ?
that's telling you that everything is OK with rails , and hum is coming from input wire harness
rearrange them and you'll have hum free amp
for test , connect just coax cable to pcb input , and just RCA (isolated from chassis) on end of coax
then tell us is there any hum
that's telling you that everything is OK with rails , and hum is coming from input wire harness
rearrange them and you'll have hum free amp
for test , connect just coax cable to pcb input , and just RCA (isolated from chassis) on end of coax
then tell us is there any hum
Music should disappear when inputs are shorted to ground. I had a tube amp that had a switch that did this so you could swap cables, or preamps without powering down the power amp.
Zen Mod is just chasing down where your hum is coming from...
Russellc
Took me a while to catch up with his idea, but this morning it hit me.
learning as we go 🙂
My integrated Aleph J project has come to the end.
I was a little worried before firing it up for the first settings, so I did this in my garden.
Then, once bias and offset carefully set, I made the first test with crappy speakers bought 10€ in a second hand store. They survived, so I plugged my Petite Onken.
Here are some pictures of the finished amp:
My main fear was noise, but I'm very happy with the result. The right channel is dead silent (I first thought I did not plug the speaker correctly). There's a slight hum on the left channel I can hear when I put my head 5 cm to the loudspeaker. The wiring of the left channel is longer and is travelling across the chassis, I think it can explain this difference.
I'd like to thank those who helped me making this amp. 6L6 and Zen Mod, of course, but also all the guys who gave usefull informations in this thread and Soundhappy, for the resistors.
Mikael
I was a little worried before firing it up for the first settings, so I did this in my garden.
Then, once bias and offset carefully set, I made the first test with crappy speakers bought 10€ in a second hand store. They survived, so I plugged my Petite Onken.
Here are some pictures of the finished amp:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
My main fear was noise, but I'm very happy with the result. The right channel is dead silent (I first thought I did not plug the speaker correctly). There's a slight hum on the left channel I can hear when I put my head 5 cm to the loudspeaker. The wiring of the left channel is longer and is travelling across the chassis, I think it can explain this difference.
I'd like to thank those who helped me making this amp. 6L6 and Zen Mod, of course, but also all the guys who gave usefull informations in this thread and Soundhappy, for the resistors.
Mikael
Hi Mikael
Very great diy amp congratulations !
I was thinking about your Aleph J build news so i enjoy it it's play music
and woow integrate with source selector & volume potentiometer too 😉
Gain is ok ? Little hum tip maybe shielded wire bring more background silence
or keep signal wire more distant from xformer.
All 230 V wires in center and far possible from RCA, XLR and speaker outputs.
I am curious about my AJ version sound with new Mills wirewound source resistors.
Best regards
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Not enough light now (it's 10PM here), you'll have to wait.😉
Gain should be ok. I have only listened at low level for the moment (to respect the sleep of my new born child) and tue pot was between 8 and 9 o'clock. It should leave a good margin for higher levels.soundhappy said:Hi Mikael
Very great diy amp congratulations !
I was thinking about your Aleph J build news so i enjoy it it's play music
and woow integrate with source selector & volume potentiometer too
Gain is ok ? Little hum tip maybe shielded wire bring more background silence
or keep signal wire more distant from xformer.
All 230 V wires in center and far possible from RCA, XLR and speaker outputs.
I am curious about my AJ version sound with new Mills wirewound source resistors.
Best regards
@ Mikael
New born child new diy amp et la vie est belle.
Good evening
Christophe
Congrats on both!🙂
Russellc
who cares for music ?
that's telling you that everything is OK with rails , and hum is coming from input wire harness
rearrange them and you'll have hum free amp
for test , connect just coax cable to pcb input , and just RCA (isolated from chassis) on end of coax
then tell us is there any hum
Back again, had some free time so i did 3 things, i twisted al lot cables that werent twisted before, replaced cound carriering cable with ftp ones (except for one, volume control), and installed a coax cable between rca input and aleph pcb inputs (just one channel)
it looks like this : http://1drv.ms/1VfhrZW
btw, i added some pictures of my new neet and tidy wiring: http://1drv.ms/1LK79gs
result is that the speaker is almost dead silent, thats an improvement 🙂, but i dont hear any music, tried my cd player and DAC but i diddent hear anything, maybe because i skipped the Mez B1 and therefore no gain?
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Whose parts did you use for your "Knob extenders"? Face plate bearing, shaft, connector, L mount and so on?
Russellc
I dont think the Mez B-1 has any gain to speak of, did you "unground" the inputs?
Russellc
I bought an extender kit on a french website (kit rallonge de potentiometre 300mm). I know Hifi Collective in UK has the same kit, I think it must be possible to find this kind of thing in the US.
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A picture of the amp with a Petite Onken on its side.
An externally hosted image should be here but it was not working when we last tested it.
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