pultec eq section in bypass circuit

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Coldsnow

Well-known member
Joined
Feb 6, 2005
Messages
296
Location
Ohio
Hi all.  I made a pultec makeup stage with API opamps that I want to use just for the sound without eq but I need to use the eq in bypass so the gain is correct.  Does someone know of a schematic I can follow that will just have the bypass parts?  Odd request I know
 
roughly equivalent circuit to gyraf pultec in bypass would be
input -> 10k -> output -> 1k -> ground

alternatively you could use a 10k-ish pot, ground ccw, input cw, output wiper and find the setting that matches the level of 'no-eq-inserted'.

both of these are basically providing a voltage divider to reduce the gain, so that with the amp stage in, it's roughly unity again.

hope this helps.
 
So the secondary of the transformer after the 620 ohm zobel to a 10k and a 1k.  The 10k goes to the input of the makeup and the 1k to ground?
 
yes 10k and 1k in series between input transformer secondary and ground (10k first).
output to makeup from inbetween the two resistors.

you are basically trying to lose the 18dB-ish gain the standard pultec ampstage provides.
 
Coldsnow said:
I made a pultec makeup stage with API opamps that I want to use just for the sound without eq but I need to use the eq in bypass so the gain is correct.

Hi all,

I've finished my MEQ5s and PEQ1 (gyraf) filters.
Coldsnow, can you share the schematic of your makeup AMP.
I'm shure, they're a lot of people interested by this part.
i've ordered 4 2520 clone to PPA in the white market.
Thank's you
Creal
 

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