Split channel,off of first plate?
Moderators: pompeiisneaks, Colossal
Re: Split channel,off of first plate?
TSC is wrong, correct value is a little bit above 600 Ohm.
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renshen1957
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Re: Split channel,off of first plate?
KOC uses transistors to mute each channel, works very well.V2 wrote:your original plan looks good to me. R7 is in series with R8, so there won't be a load problem on that arm.
Kevin O'Connor does something similar with his Standard preamp design.
Best regards,
Steve
Every Tom, Dick, and Harry is named Steve
Re: Split channel,off of first plate?
How has that been identified? Is there anything obviously wrong with my test method (described previously)?correct value is a little bit above 600 Ohm
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martin manning
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Re: Split channel,off of first plate?
Blencowe explains the derivation of Zo for a CF in his Preamps book. It's given as 1/(1/Rk + 1/ra + gm). For a 12AX7 ra is 63k, and gm is 1.6 mA/V. Rk is typically 56-100k... gm dominates, so Zo is basically 1/gm = 625.