Pultec MB-1 transformerless in/out

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k brown

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Joined
Jul 6, 2021
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14
Location
San Francisco
I built this MB-1 clone w/o trafos on input or output; seems to sound fine, but did I do anything stupid or sub-optimal? Questioning mostly the input grid R: need to be this high value, make any difference? Inputs are usually fed directly from Nelson Pass B1 Buffer FET circuit.

Thanks
 

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ruffrecords

Well-known member
Joined
Nov 10, 2006
Messages
13,517
Location
Norfolk - UK
Your circuit looks fine to me. The grid resistor is only there to connect the grid to 0V at dc so the tube gets properly biased. It can be any value you like below 1Meg.

Cheers

Ian
 

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