help designing 6L6G S.E. amplifier

[retrovox]

Originally Posted by chrish

This data sheet may be helpful http://www.retrovox.com.au/STC807.pdf The 807 and 6L6 are from the same family of tubes, so the data will be valid.

I have uploaded STC 6L6G application report as well. 23 pages.

See http://retrovox.com.au/STC6L6G.pdf

David

[SemperFi]

Why drive a 6L6 into A2 when the plate load is 5kohms, and b+ this low?

[dirkwright]

Originally Posted by Eli Duttman

BTW, the place for a CCS in a differential gain block (LTP) is in the tail. Do not CCS load the anodes, especially if a tail CCS is used. Choke loading LTP anodes is fine.

I'm curious, can you explain why CCS is a bad idea for the loads on the LTP? It's apparently done in the tube world and it's common in the solid state one.

I agree the best place for the CCS is in the tail of the LTP.

[SemperFi]

I can see potential problems if the CCS drift and you get serious shift in your quiescent voltages. The CCS in the tail can fight the CCSs in the plates in a way. But if you shunt the CCS with a high value resistor this shouldn't be a problem, or make sure eventual drift is common and tracks.

[SemperFi]

Btw Maurizio, you are aware using b+ of 240volts will produce a very low output power? Usually these tubes are used with > 400V. It will work, but you'll have loudness troubles.

[dirkwright]

Originally Posted by SemperFi

I can see potential problems if the CCS drift and you get serious shift in your quiescent voltages. The CCS in the tail can fight the CCSs in the plates in a way. But if you shunt the CCS with a high value resistor this shouldn't be a problem, or make sure eventual drift is common and tracks.

I don't know what others have done about this possibility, or even if it's a serious problem. I wish I knew more about circuit design.