I find this thread very interesting. I've got an Aleph 4 and an F5 and both are completely black silent even with my ears pressed against the speaker cones.
It would be interesting to see what happens if the PSU is replaced with car batteries. That would tell us if the problem is mains borne.
It would be interesting to see what happens if the PSU is replaced with car batteries. That would tell us if the problem is mains borne.
I have spies
Actually, I got a notification that you subscribed to my channel. Thank you, BTW.
Aha
I have checked all the 16 main circiuts in my house now. It is no difference if all except the HiFi circuit is disabled. But....i measure 160 volt from one phase to earth on different places in the house, this is wrong and it is leak to earth some place, maybe at a neighbour?
If this is relevant for the noise i dont know.
Normally the gain setting on the XO is max both for high and low. But now The XO is disabled, i am testing a 100% passive XO.
If this is relevant for the noise i dont know.
Normally the gain setting on the XO is max both for high and low. But now The XO is disabled, i am testing a 100% passive XO.
Good to know.
Check as ZM suggests above. If you place an ear to the case, is the transformer buzzing?
I have posted two more videos at YouTube.
The conclusion is that the basic amplifier noise is quite similar with another 26 dB gain class A amp i have. My other amp is more dark sounding than XA30.5 therefore it is a tiny bit more quiet.
I discovered now that with RCA cables the noise increase further when i turn The volume from mute (zero) and up. This is similar on both power amps.
No other equipment like dac, active xover etc, are turned on.
The conclusion is that the basic amplifier noise is quite similar with another 26 dB gain class A amp i have. My other amp is more dark sounding than XA30.5 therefore it is a tiny bit more quiet.
I discovered now that with RCA cables the noise increase further when i turn The volume from mute (zero) and up. This is similar on both power amps.
No other equipment like dac, active xover etc, are turned on.
I thought we were testing with nothing connected to the amp? We really need to nail down one piece at a time. And the first question is: what is the amp contributing?
So you have an ACVM. Have you tried measuring AC across the speaker terminals? (w/ no RCA cables connected to the amp)
If the amp alone is quiet, then try floating the preamp.
So you have an ACVM. Have you tried measuring AC across the speaker terminals? (w/ no RCA cables connected to the amp)
If the amp alone is quiet, then try floating the preamp.
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Yes, first i tested without preamp and noise is present with the amp alone
Now i tested with preamp and the basic noise level is the same when mute is activated
Now i disconnected the preamp and i measure 0,7 V across the speaker terminals
My $40 DMM is useless below 30 or 40 mV AC, so that was probably a silly suggestion, but I though it might be worth a try. Based on what you've posted recently, I'm sticking with the guess from #58 That you're seeing 2-3 mV of noise. But why? Trolls? I'll have to sleep on it.
Do you know the noise spec of that other amp that you said was about the same?
Do you know the noise spec of that other amp that you said was about the same?
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