F5 - is normal ICs twist out the Hum? - diyAudio
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Old 28th November 2012, 07:07 PM   #1
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Default F5 - is normal ICs twist out the Hum?

I know much has been written about the hum, but I have done all, the last thing I did was twist the cables and ICs hum almost disappears! It remains a bit, but this is no solution.

No longer know what to do, is a small hum, touching the ear to the speaker is quite perceptible.

I made a star as the image is, the masses of the left channel and right channel bind to this connects to a central point, this point connects to the mass of the PSU.

I have the source with 8 capacitors 15,000 each, had bought a pack of 10, 2 left over, I'd better turn over these 2 who are outside? Where would be best to connect the PSU? One for each channel at the entrance of the source at 2.2 K?

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I made a star as the image is, the masses of the left channel and right channel bind to this connects to a central point, this point connects to the mass of the PSU.

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Last edited by Blink_PT; 28th November 2012 at 07:09 PM.
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Old 28th November 2012, 07:32 PM   #2
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Do not connect the ground between the two input sockets. The amp 2 socket should have its ground back to the gnd track on amp 2, just like you did for amp 1.
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Old 28th November 2012, 09:42 PM   #3
Zen Mod is offline Zen Mod  Serbia
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make like this , but without red bridge fat wire

if small hum residue , put red bridge fat wire directly and in shortest way , between two pcbs (grounds)
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Old 29th November 2012, 12:15 AM   #4
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Quote:
Originally Posted by Zen Mod View Post
make like this , but without red bridge fat wire

if small hum residue , put red bridge fat wire directly and in shortest way , between two pcbs (grounds)

Thanks Zen Mod, did your scheme but was more hum.

Tomorrow I will turn the bridge with such large wire and see if that solves the problem ...
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Old 29th November 2012, 01:35 AM   #5
dazed2 is offline dazed2  Canada
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I used to have hum too until I configured it like so:
No input ground from RCA's to the amp boards at all.
RCA hot to amp board, the Hot to the speaker, and the V+ and V- from the power supply. No ground at all on the amp board.
The RCA ground and speaker return I have connected to the PSU board ground then through the thermistor then chassis. AC ground is connected at the same point to the chassis as well.
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Old 29th November 2012, 08:38 AM   #6
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Quote:
Originally Posted by dazed2 View Post
I used to have hum too until I configured it like so:
No input ground from RCA's to the amp boards at all.
RCA hot to amp board, the Hot to the speaker, and the V+ and V- from the power supply. No ground at all on the amp board.
The RCA ground and speaker return I have connected to the PSU board ground then through the thermistor then chassis. AC ground is connected at the same point to the chassis as well.

Do not quite understand what she said!.

A scheme would be excellent. thank you
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Old 29th November 2012, 09:19 AM   #7
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally Posted by Blink_PT View Post
Thanks Zen Mod, did your scheme but was more hum.

Tomorrow I will turn the bridge with such large wire and see if that solves the problem ...
you have pots on sch , but I can't see them on pictures ?
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Old 29th November 2012, 09:36 AM   #8
Murdoc is offline Murdoc  Germany
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Hi!
This helped me to get my whole system hum free but also I learned why: Audio Component Grounding and Interconnection
It's a bit longer read than staring to a picture, but it pays off!

(I even don't need the CL60 or diode bridge!)

Or look here and while you're listending to hum free music, read the above. AlephWiki : Anschlussplan
Lautsprecher = speaker
zentraler Massepunkt = Star Ground

Kind regards
Matthias
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Old 29th November 2012, 10:12 AM   #9
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Depending on how good the transformer is try shielding the input wire.

In my F5 i have a toroid of unknown origin and without shielded input cables it hums !
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Old 29th November 2012, 10:26 AM   #10
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Originally Posted by Zen Mod View Post
you have pots on sch , but I can't see them on pictures ?
Yes, I use pots Vishay Spectrol...


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