Using BA283AM as makeup gain in a Pultec with Neve trafos

I am just putting a few modules together to to do the following (thanks to Peter P and others for the help):

Original Green Meanie 31267
Into Gyraf Pultec Filter Boards
Through Fabio BA283 output into Carnhill LO1166

Some of this stuff is waay over my head - but I have done my reading and tried to make sense of it all
I have hooked up the bits, soldered and de-soldered

31267 is configured for 10k:600R
+ in into Pin 2
Pins 3/4 joined
- in into Pin 5
Pin 6 ground

Pins 7 and 8 joined to + out
Pins 9 and 10 joined to ground

The LO1166 is configured for 600:600

Now doing the reading...
31267 in that configuration gives a 12db loss
The LO1166 gives a 1db loss
The filter circuit gives a 18-20db loss

So that makes a 31db - 32db loss

The BA283 output stage can give a 15db gain
But with the following resistors added to RGx it can be adjusted:
1k5...18db
1k2...20db
470...25db
220...30db
110...35db

Can somebody be a darling and give me a few ideas on who to fine tune the db ratings to give somethign a bit more precise in the 30-35db range?

or is it not worth it - set it to 35db and then forget it?

Hi
It is more usual to have input transformer as 1:1 as the level loss must be made up later and it gets noisy.
To get closer gain resistor values, draw a grapheither on paper!! or in excel or whatever, then look up nearest values.
Matt S

Could you solder in a pot, adjust for unity gain through the eq and then take it out and measure it? No practical experience doing this so there could be reasons why it is a bad idea,

cheers,
Ruairi

Soldering in a pot is a reasonable idea. Fitting a preset (or pot) allows you to get it exactly right
Matt S

Hey UK, try a 500R 25-turn pot in series with a 100R in place of RGx....that should allow you to trim between roughly 23dB and 36dB.

HTH
Tom

Thanks guys - will tamper

So if I replace my 31267 with a 10468 I might get closer - off to check and read

i don't know what a green meenie is, but the rest of it sounds brilliant!

[quote author="Matt Syson"]Hi
It is more usual to have input transformer as 1:1 as the level loss must be made up later and it gets noisy.
[/quote]
I wonder why Neve didn't .

[quote author="Bryson"][quote author="Matt Syson"]Hi
It is more usual to have input transformer as 1:1 as the level loss must be made up later and it gets noisy.
[/quote]
I wonder why Neve didn't .[/quote]


Well they never made a pultec...


M@