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Old 20th March 2013, 11:44 PM   #2691
stajo is offline stajo  Sweden
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Current wasnt flowing because the cathodes had no relation to ground, which in this case is minus in the circuit. The circuit was open and could not pass current. If last filtercap was not grounded, it just stopped filtering, but it has nothing with current flow to do since a capacitor can not pass current.

Last edited by stajo; 20th March 2013 at 11:46 PM.
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Old 20th March 2013, 11:52 PM   #2692
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Quote:
Originally Posted by andyjevans View Post
OK. First get the filament supply right, then look at the PSU. Don't connect up the B+ until the filament supply is working correctly. You should now have about 11v on the top of the cathode resistor, and the bottom is connected to ground. What is the actual voltage you have now on top of the cathode resistor?
I have 9,33V left channel & 9,75V right channel, my cathode resistor is 10 ohms.

Last edited by merlin el mago; 20th March 2013 at 11:54 PM.
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Old 20th March 2013, 11:56 PM   #2693
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With filament bias it is important to connect everything in the right order. This is -

1. Connect Rod regulator up. Minus to ground, plus to pin 4 of 26
2. Connect resistor from pin 1 of 26 to ground.
3. Insert tube and turn on regulator
4. Measure across pins 1 and 4 for 1.5v
5. Measure from pin 1 to ground - for 10 ohm resistor should be about 10v, since current is 1 amp. Use ohms law.
6. Leave the supply on for about 30m to make sure it is stable.

AFTER you have done all this and the voltages measure the same after 30m, you can connect the B+.
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Old 20th March 2013, 11:59 PM   #2694
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Quote:
Originally Posted by merlin el mago View Post
I have 9,33V left channel & 9,75V right channel, my cathode resistor is 10 ohms.
That's pretty good - you have about 950mA current, so your voltage across the filament should be about 1.4v. Slightly starved - very good.

Now you can connect the B+

What I would say, though, is don't work late because you can make mistakes. I always test circuits in the daytime, never late in the evening.

Andy

Last edited by andyjevans; 21st March 2013 at 12:02 AM.
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Old 21st March 2013, 12:03 AM   #2695
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Quote:
Originally Posted by andyjevans View Post
With filament bias it is important to connect everything in the right order. This is -

1. Connect Rod regulator up. Minus to ground, plus to pin 4 of 26 CONNECTED TO PIN 1, DONE
2. Connect resistor from pin 1 of 26 to ground. CONNECTED TO PIN 4, DONE
3. Insert tube and turn on regulator DONE
4. Measure across pins 1 and 4 for 1.5v DONE
5. Measure from pin 1 to ground - for 10 ohm resistor should be about 10v, since current is 1 amp. Use ohms law. FROM PIN 4 TO GROUND 10V DVM PLUS LEAD TO PIN 4 DVM MINUS LEAD TO GROUND
6. Leave the supply on for about 30m to make sure it is stable. OK

AFTER you have done all this and the voltages measure the same after 30m, you can connect the B+.
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Old 21st March 2013, 12:07 AM   #2696
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B+ at plate left channel 67,2VDC
B+ at plate right channel 68,8VDC
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Old 21st March 2013, 12:12 AM   #2697
stajo is offline stajo  Sweden
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Ok. Have you split somewhere in between channels in the PSU filter? That result is around what it would be for 10-12ish mA. Use one RC per channel as last RC. Lower the R until you're there.
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Old 21st March 2013, 12:14 AM   #2698
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Thanks guy it's too late and mistakes can be done easily as Andy said, good night, see you tomorrow to arrange B+
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Old 21st March 2013, 12:15 AM   #2699
stajo is offline stajo  Sweden
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From 40 uF make Y-split with 2 20k resistors and put another 220uF to the new rail. Yea, nightie night. Gotta save some for the next day.
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Old 21st March 2013, 09:56 AM   #2700
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Good morning stajo, yes you are right I splited B+ for the two tubes.
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