• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

#26 pre amp

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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new measurements right channel
 

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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.

Salas advice is set the SSHV2 to 30mA, 20mA consums the reg itself at the other 10mA for the 26.
 

iko

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Joined 2008
You just measured it. It's the voltage across the 100R resistor, divided by 100.

In my opinion it would be easier for you to use a VR150 tube with a DN2540 CCS, than the Salas shunt reg. Normally I would recommend the shunt reg, but look what troubles you already had with this circuit.
 
In my opinion it would be easier for you to use a VR150 tube with a DN2540 CCS, than the Salas shunt reg. Normally I would recommend the shunt reg, but look what troubles you already had with this circuit.

I'd say first measure the ripple wtth the scope before the 15/20k resistors, because that is what the shunt/CSS/gyrator whatever has to deal with. You know the current:) Then ask the big guys, not me. I'm not your man on that;)
 
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You just measured it. It's the voltage across the 100R resistor, divided by 100.

In my opinion it would be easier for you to use a VR150 tube with a DN2540 CCS, than the Salas shunt reg. Normally I would recommend the shunt reg, but look what troubles you already had with this circuit.

I have two SSHV2 working without any problem: one in Valve Itch and another a ECC81 mu follower lineamp

For 26 due to the fact I bought a small chassis by my mistake I want try other kind of reg like your CCS+gyrator, I ask again: can I use it togheter the OPT or you believe better to avoid and go for SSHV2 or VR150 tube with DN2450?

TIA

N.B. Don't worry Iko, troubles is my way to learn.