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Old 25th June 2012, 11:51 AM   #921
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Its probably layout or error. I never ceased to be amazed how often i miss something simple. Check every component and node. Draw it on paper as you follow it over the board. You might be surprised. I doubt a beoskie psu is noisy. Could be wrong. Fwiw, i found i was using a really noisy transformer for my filament voltage. I think it was having trouble with the current draw. Cheapo Radio Shack.
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Old 25th June 2012, 11:54 AM   #922
cjkpkg is offline cjkpkg  United States
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The toroid I have has a 3 or 4 A 6.3V winding so I would prefer to use that...it will still give me a B+ of just north of 300 - about 315 regulated.
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Old 25th June 2012, 12:19 PM   #923
stajo is online now stajo  Sweden
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What does the hum sound like, is it 100 Hz?
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Old 25th June 2012, 12:58 PM   #924
cjkpkg is offline cjkpkg  United States
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I do not have a scope but it sounds to me a little higher pitched than 60HZ hum...so I guess it could be 100hz...

and it is very loud...
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Old 25th June 2012, 01:28 PM   #925
stajo is online now stajo  Sweden
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Rectified 60 Hz AC gives 120 Hz. Try measure AC with a DMM on your B+. If it shows above or anywhere near 1 volt you have a PSU problem. Should be a few millivolts. If its on the millivolt level, go search on the amplifier card.

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Old 25th June 2012, 01:46 PM   #926
cjkpkg is offline cjkpkg  United States
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here is a question...both PSU's I was using reference the heaters to B+/4. I see the schematic does not show this.

Any thoughts on this as a possibility?
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Old 25th June 2012, 01:56 PM   #927
stajo is online now stajo  Sweden
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Does that mean that heaters are lifted to about 70 v above ground? 6V6 should cope with that. Is it DC or AC on heaters?

I think I see that what looks like your cathode bypass caps is very close to the tubes. They get hot wich can affect their condition and reflect back on the tubes if they become unstable. I would keep caps futher away from hot tubes.

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Old 25th June 2012, 02:02 PM   #928
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Question. Have youused these psu boards before and did you have a noise problem then?
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Old 25th June 2012, 02:51 PM   #929
cjkpkg is offline cjkpkg  United States
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The PS-1 I am using is also the same board I am using on a phono preamp. VERY quiet.

heaters are regulated DC

I was actually thinking about swapping this PS-1 to my tetra sans and see if it is quiet over there and vice versa.

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Old 25th June 2012, 03:00 PM   #930
Salas is online now Salas  Greece
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That one is almost like a Mosfet Maida. If there is a psu line problem it could be bad interaction not inherent.
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