How to wire a 500K gain control pot to V672/1?

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Smilan
Posts: 2
Joined: Thu Jun 16, 2022 7:59 am

How to wire a 500K gain control pot to V672/1?

Post by Smilan »

Hi Joe,
I'm working on racking two V672 pres and I'm having troubles wiring the gain pot.
I'm following this wiring diagram that I saw on groupdiy and I have some issues:
Image
JLM Audio said:
"We also removed the original gain trim pot completely and strapped the wiper tag to the negative end (pin 4 to pin5 on circuit) so we could get all the negative feedback to the input transformer to get the 36dB minimum gain for more gain range."

I don't sure I understood this part.
I disconnected the original gain trim from the circuit and connected a 500K log pot to pins 9 and 10.
I'm looking at the wiring diagram and don't sure where to connect pin 3 of the 500K pot?
The overall gain is very strong and the new gain pot does not affecting on the gain.
What have I done wrong?

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Joe Malone
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Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
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Re: How to wire a 500K gain control pot to V672/1?

Post by Joe Malone »

Smilan wrote:
Mon Jul 04, 2022 5:59 pm
Hi Joe,
I'm working on racking two V672 pres and I'm having troubles wiring the gain pot.
I'm following this wiring diagram that I saw on groupdiy and I have some issues:
Image
JLM Audio said:
"We also removed the original gain trim pot completely and strapped the wiper tag to the negative end (pin 4 to pin5 on circuit) so we could get all the negative feedback to the input transformer to get the 36dB minimum gain for more gain range."

I don't sure I understood this part.
I disconnected the original gain trim from the circuit and connected a 500K log pot to pins 9 and 10.
I'm looking at the wiring diagram and don't sure where to connect pin 3 of the 500K pot?
The overall gain is very strong and the new gain pot does not affecting on the gain.
What have I done wrong?
Once you remove the original R1 trimpot you need to link the S wire from the wiper to the A wire that goes to pin 4 of the input module. Otherwise the gain pot will do nothing and you will be stuck on full gain as the S wires goes to pin 9 the new 500k gain pot is connected to. The third E wire to the 5.6k is left disconnected.
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Joe :-)
JLM Audio
Capturing Audio without Injury

Smilan
Posts: 2
Joined: Thu Jun 16, 2022 7:59 am

Re: How to wire a 500K gain control pot to V672/1?

Post by Smilan »

Thank you very much!
It working now as it should :)

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Joe Malone
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Posts: 2081
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: How to wire a 500K gain control pot to V672/1?

Post by Joe Malone »

Smilan wrote:
Mon Jul 04, 2022 6:56 pm
Thank you very much!
It working now as it should :)
Cool great to hear you have it working 8) :D
Joe :-)
JLM Audio
Capturing Audio without Injury

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