Trident A Range Overload LED Calibration?

[jeffbro]

I'm working on a pair of A Range modules and in one of them the OL indicator is triggering much earlier than the other, and at a level that is nowhere near an overload.  Does anyone know the correct way to adjust the two OL circuit trimmers?

FWIW these are SMS built modules which drive the OL circuit from the output amplifier rather than from the output of the EQ section as shown in the schematics. 

Jeff

 

[JohnRoberts]

It is difficult to measure past clipping. I used to set my console overload thresholds at 3dB before clipping. Some manufacturers may adjust up closer to saturation to appear like they are providing more head room.

JR

 

[pucho812]

I'm working on a pair of A Range modules and in one of them the OL indicator is triggering much earlier than the other, and at a level that is nowhere near an overload.  Does anyone know the correct way to adjust the two OL circuit trimmers?

FWIW these are SMS built modules which drive the OL circuit from the output amplifier rather than from the output of the EQ section as shown in the schematics. 

Jeff

Got a photo?

 

[jeffbro]

A photo of the module?  No point - the exterior and interior are identical to Trident-made modules.  I don't remember the story but I believe SMS had permission to build clone modules, even when the consoles were current.  I think they may have bought PCBs and some parts from Trident.  I may have heard that story in this forum and maybe someone will chime in with more detail.

Part of what is confusing me is the purpose of the two trimpots.  One sets the amount of audio going into the OL circuit.  Is the other to set a trigger threshold?  If that's the case I would have thought it simpler/cheaper to have a fixed threshold and just vary the audio going into the monitoring circuit with the one trimpot.

 

[pucho812]

sorry  who is SMS?

the only people I knew of who built a-range modules outside of trident was Cherokee studios.

It's why I am curious to see inside.

 

[jeffbro]

I've shared all I remember but the first return from a Google search was this
https://www.gearslutz.com/board/high-end/80842-trident-range-7.html
which must be what I remember reading many years ago.

I'm still hoping someone can address the two trimpots and their correct set up.

 

[pucho812]

I've shared all I remember but the first return from a Google search was this
https://www.gearslutz.com/board/high-end/80842-trident-range-7.html
which must be what I remember reading many years ago.

I'm still hoping someone can address the two trimpots and their correct set up.

Interesting.