aazaa

Re: Push-pull microphone preamp with UTC LS and Tamura transformers
« Reply #60 on: March 21, 2021, 05:50:17 AM »
Not sure which data sheet you are reading but the E88CC one (which is the same tube) says its 150V (cathode positive wrt filament) and 100v if negative.

Cheers

Ian

RCA 6922 specifications 5-62: "Heater negative with respect to cathode max. 60 volts"
Error in RCA sheet?

Paul





ruffrecords

Re: Push-pull microphone preamp with UTC LS and Tamura transformers
« Reply #61 on: March 21, 2021, 04:12:02 PM »
RCA 6922 specifications 5-62: "Heater negative with respect to cathode max. 60 volts"
Error in RCA sheet?

Paul
Interesting. The tube I normally use is  the Electroharmonix 6922EH and its data sheet says says Vk plus or minus 200V.

Looks like a 6922 is not always a 6922 and is not equal to a E88CC.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

aazaa

Re: Push-pull microphone preamp with UTC LS and Tamura transformers
« Reply #62 on: March 28, 2021, 12:43:33 PM »
An additional transformer is ordered to change the PSU to + 400V.
+ 250V across the ECC82 output tube will result in much more headroom without straining the tube to the limit.

The modified circuit below will be refined when the transformer is in.

Paul


 

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