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Old 8th October 2006, 03:06 AM   #11
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Oh, for the love of... Here:

For what it's worth, I don't think the granting of a patent guarantees the excellence of a design. I'm basically a cheap guy by nature. EL509s are getting scarce and pricey. If I could modify the circuit for a different tube that I have on hand, I'd do it. I've got 6KV6s I'd like to try. Maybe someone else has other tubes. It's the knowledge I'm after. I think in this case it might just be the grid and cathode resistors values. I just don't know how to translate tube characteristics into circuit values.

Knowing the history of BR's responses to tube substitution questons in his products on the Transcendent message board, I thought I'd have more luck here.
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Old 8th October 2006, 04:28 AM   #12
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Thought the Russians or the Chinese still made EL509's but failing that there should be a plentiful and cheap supply of PL509's.
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Old 8th October 2006, 05:26 AM   #13
5u4 is offline 5u4  United States
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I would think the main concern would be the bias voltage.

The purpose of the 100k grid stoppers are to isolate each tube in case of a grid short.

Don't know of any reason to change the value of the 30K grid to bias resistors for a 6KV6 or due to the different driver...... or the 170V...... or the screen resistors. Perhaps one of the EE's will help out here.

The 2 ohm cathode resistors are to help prevent a tube from hogging current.

Perhaps you already know all this. If you do I appologize, just trying to help.
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Old 8th October 2006, 06:13 PM   #14
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Thanks 5U4,

No tidbit of information is wasted on me since I'm basically just a schematic jockey.
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