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Old 21st March 2013, 07:18 PM   #2801
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Quote:
Originally Posted by ikoflexer View Post
If you take the tube from the left channel and put it in the right channel, and if you still measure 0.18V across the 100R resistor, then the problem is not an old tube in the right channel.
OK I swap the tubes & measures voltage across 100R resistor
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Old 21st March 2013, 07:18 PM   #2802
stajo is offline stajo  Sweden
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Originally Posted by merlin el mago View Post
So can't change the right channel tube as Iko suggested?
Yes of course. But I would put same values (20k) on both rails to see if its the tubes that differ.

One takes 4,6 and the other 6,4 now, and thats a big percentual difference with almost the same B+
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Old 21st March 2013, 07:20 PM   #2803
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Originally Posted by merlin el mago View Post
OK I swap the tubes & measures voltage across 100R resistor
If you have 20 k on both filterlanes, the measurements will be more accurate over that then over the 100R, when changing tubes
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Old 21st March 2013, 07:22 PM   #2804
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Sounds like the other tube is old.
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Old 21st March 2013, 07:32 PM   #2805
stajo is offline stajo  Sweden
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Now concentrate on the fresh tube. Let the other one sit but measure on the fresh. What your up to now is to decide how to drop the 90 volts. A resistor gives the feeding an unnessesary high impedance. You should consider a shunt. It drops without adding impedance. VR tubes were suggested. SSHV2 also drops that easy at those currents (in fact im not sure how well it behaves under 10 mA, ask Salas or other guys that has used it here. Glow tubes are nice. 85+85 gives 190 Volts and 40 for SSHV2.

Tho, if using SSHV2, check first with your livee circuit. Use a dummy load for 25 mA/channel. Easy to forget that SSHV eats current that lowers original voltage, and you might end up to low.
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Old 21st March 2013, 07:32 PM   #2806
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Originally Posted by ikoflexer View Post
Sounds like the other tube is old.
Same tube now measures 0,490V across 100R, I adjusted the tube at the socket it seems don't do good contact
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Old 21st March 2013, 07:34 PM   #2807
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Originally Posted by merlin el mago View Post
Same tube now measures 0,490V across 100R, I adjusted the tube at the socket it seems don't do good contact
your home
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Old 21st March 2013, 07:40 PM   #2808
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new measurements right channel
Attached Images
File Type: jpg felipe 26 measurement right channel.jpg (142.2 KB, 152 views)
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Old 21st March 2013, 07:43 PM   #2809
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Quote:
Originally Posted by stajo View Post
Now concentrate on the fresh tube. Let the other one sit but measure on the fresh. What your up to now is to decide how to drop the 90 volts. A resistor gives the feeding an unnessesary high impedance. You should consider a shunt. It drops without adding impedance. VR tubes were suggested. SSHV2 also drops that easy at those currents (in fact im not sure how well it behaves under 10 mA, ask Salas or other guys that has used it here. Glow tubes are nice. 85+85 gives 190 Volts and 40 for SSHV2.

Tho, if using SSHV2, check first with your livee circuit. Use a dummy load for 25 mA/channel. Easy to forget that SSHV eats current that lowers original voltage, and you might end up to low.
Salas advice is set the SSHV2 to 30mA, 20mA consums the reg itself at the other 10mA for the 26.
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Old 21st March 2013, 08:17 PM   #2810
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Originally Posted by merlin el mago View Post
Salas advice is set the SSHV2 to 30mA, 20mA consums the reg itself at the other 10mA for the 26.
Correct. But how much does your tubes consume?
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