Langevin AM-4 console monitoring

This is the monitor path of a Langevin AM-407 output module. The top right pair (R40, 41) comes from the output transformer. The top left pair  (R36, 38) comes from the reverb return, but normally just has a 130r resistor switched in shunted across. The bottom right pair (R42, 43) is monitor out hi and lo.

The board as is has no monitor level control, just that fixed pad, signal taken from the same point as the mix outs. I need a monitor control.

I have a lot of questions, but for simplicity's sake, what's going on here? Is that network of R39, 40, and 41 a U-pad? Does R31 and 35 make it a T-pad?

I'd like to make this adjustable, but i can't get my thoughts straight, any help is appreciated

It is a simple mix of the MON out and the rev return (as shown in the block diagram). The reverb return can be switched in or not as required. The MON out is padded down to about -20dBu (that's the U pad) before it is mixed with the -20dBu rev return.

Do you want to just add a level control to the -20dBu MON out?

Cheers

Ian

Thanks Ian.

Ideally I'd like to replace that pad with something adjustable, be it U-pad or something else.

My goal is something that would go from no attenuation to full off

Dreams said:

Thanks Ian.

Ideally I'd like to replace that pad with something adjustable, be it U-pad or something else.

Click to expand...

Do you still want to mix in the rev return?

Cheers

ian

ruffrecords said:

Do you still want to mix in the rev return?

Cheers

ian

Click to expand...

Makes no difference to me. The reverb return will either be mixed in with the program path or switched out, so that leg could stay or go as needed

Dreams said:

Makes no difference to me. The reverb return will either be mixed in with the program path or switched out, so that leg could stay or go as needed

Click to expand...

Losing the rev return into the MON feed simplifies things. If you just want a simple level pot that goes to zero you could use what I call the Neve trick - it was used on some Neve MON outs. You simply replace the current network with  a 2K LIN pot between hot and cold and add a 1K slug resistor from the wiper to cold. Your output comes from wiper (hot) and cold.

Cheers

Ian

Hello

ruffrecords said:

Neve trick - it was used on some Neve MON outs. You simply replace the current network with  a 2K LIN pot between hot and cold and add a 1K slug resistor from the wiper to cold. Your output comes from wiper (hot) and cold.

Click to expand...

Can we call this an out of phase blender ?  ;D

Cheers
Zam

ruffrecords said:

You simply replace the current network with  a 2K LIN pot between hot and cold and add a 1K slug resistor from the wiper to cold. Your output comes from wiper (hot) and cold.

Click to expand...

I like it. Simple, and with linear pots so the stereo tracking will be good. Finding a pot with the right sizes and characteristics has been...fun...but i think I've got something now, so I'll give it a shot. Thanks!

Dreams said:

I like it. Simple, and with linear pots so the stereo tracking will be good. Finding a pot with the right sizes and characteristics has been...fun...but i think I've got something now, so I'll give it a shot. Thanks!

Click to expand...

2K is an odd value. For monitor pots like this I usually go  Blore Edwards who will make them to order at any value:

https://www.blore-ed.com/shop

Cheers

Ian