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Old 19th April 2004, 02:47 PM   #41
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Default New 5U4G

I've just tried a brand new 5U4G. No sparks... PC monitor interferences are back again... and the voltage drop is the same:

From +427V to +323V at 72 mA (mono)
From +427V to +282V at 124mA (stereo)

I've also tried a new couple of Sovtek KT88

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Old 19th April 2004, 04:15 PM   #42
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I certainly agree that tube rectifier voltage drop is not constant like a silicone diode, but there is a certain drop expected with a given design. 72mA should not cause a 110V drop across the rectifier.

Go back and recheck your wiring yet again. Make sure your grounding is solid, and no loose or shorted wires. Ensure the wiring conforms to the schematic. You are getting a large current draw from the rectifier and it does not look loke it is going to the KT88. Good luck.

Thomas
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Old 20th April 2004, 06:50 PM   #43
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Thumbs up GOT IT!

Ok, I've find the bug:

Look at the pinout of the 5U4G at the schematic from my first post. 4 and 5 for the plates Ouch! really stupid... I was using only one plate.

I think I own a pint to all of you.

Anyway, thanks to this I've been learning a lot of things about power supplies.

Now V drops to +361V/80,5 mA (mono) +325V/141,5 mA (stereo)

Thank you very much
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Old 20th April 2004, 11:16 PM   #44
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Congratulations. I hope your amp sounds beautiful.

Thomas
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