Hey guys, got the Trident CB9146 clone that was up for sale a while back on Black Market. Got it all racked but have had some trouble calibrating it correctly. I've been instructed to follow the calibration procedure from the original manual but keep running into issues once I get to the threshold setting step. It's very possible I've missed something before that so I'm going to lay out what I'm doing for each step in regards to the manual. I've only calibrated an 1176 before so I'm somewhat of a noob when it comes to this stuff.
Thread about the compressor w/Manual and Schematic:
http://groupdiy.com/index.php?topic=59781.0
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1) Remove FET
I've skipped removing the FET, not sure why it would be necessary.
2) Connect a sine wave input of 1khz at 0dbm into the input socket of the channel under test and adjust the input level control to -20 dbm and the output level control to +20dbm front panel settings.
I've inserted the 1khz sine wave at 0.775 v with the correct front panel settings
3) Set the ratio 1:1 and attack + release mid way
Done.
4) Check that the signals on the collector and emitter of Q2 are equal and anti phase
Skip as I assume this is working properly.
5) Insert the FET and adjust the FET bias preset (VR trimmer pot in schematic I think) until the output signal is attenuated by approximately 6db.
I skip inserting the FET because I never removed it. I adjust the VR trimmer pot (VR Trimmer = Fet Bias Preset....I hope) so that the output on pins 2 + 3 of my output XLR read 0.385.....roughly -6dbm.
6) Adjust "Set Distortion" pre set so that positive and negative cycles are attenuated equally.
Was told by the Fourth Monkey that I can just adjust this to taste, so I do.
7) Reset the Fet Bias preset (VR trimmer, I'm assuming) so that the signal is attenuated by 0.1 dbm - Fet just starts to pinch off.
Here's where I get confused. Do I have the output signal adjusted to 0db or do I have it at -6db with the VR trimmer. Do I take off 0.1db at -6db or at 0db at the xlr output? Or am I completely doing this wrong
8) Set the front panel Ratio Control to 20:1 and adjust the threshold preset (threshold trimmer on schematic) so that the output level falls to 0dbm.
I get absolutely no voltage movement at the output xlr when I adjust the threshold trimmer. I can hear an audible change at some points but my output voltage at the xlr output never changes.
Also, this is balanced in and out correct?
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The rest of the steps are distortion and meter stuff which I have under control.
Thread about the compressor w/Manual and Schematic:
http://groupdiy.com/index.php?topic=59781.0
---------------------------------------------------------------------
1) Remove FET
I've skipped removing the FET, not sure why it would be necessary.
2) Connect a sine wave input of 1khz at 0dbm into the input socket of the channel under test and adjust the input level control to -20 dbm and the output level control to +20dbm front panel settings.
I've inserted the 1khz sine wave at 0.775 v with the correct front panel settings
3) Set the ratio 1:1 and attack + release mid way
Done.
4) Check that the signals on the collector and emitter of Q2 are equal and anti phase
Skip as I assume this is working properly.
5) Insert the FET and adjust the FET bias preset (VR trimmer pot in schematic I think) until the output signal is attenuated by approximately 6db.
I skip inserting the FET because I never removed it. I adjust the VR trimmer pot (VR Trimmer = Fet Bias Preset....I hope) so that the output on pins 2 + 3 of my output XLR read 0.385.....roughly -6dbm.
6) Adjust "Set Distortion" pre set so that positive and negative cycles are attenuated equally.
Was told by the Fourth Monkey that I can just adjust this to taste, so I do.
7) Reset the Fet Bias preset (VR trimmer, I'm assuming) so that the signal is attenuated by 0.1 dbm - Fet just starts to pinch off.
Here's where I get confused. Do I have the output signal adjusted to 0db or do I have it at -6db with the VR trimmer. Do I take off 0.1db at -6db or at 0db at the xlr output? Or am I completely doing this wrong
8) Set the front panel Ratio Control to 20:1 and adjust the threshold preset (threshold trimmer on schematic) so that the output level falls to 0dbm.
I get absolutely no voltage movement at the output xlr when I adjust the threshold trimmer. I can hear an audible change at some points but my output voltage at the xlr output never changes.
Also, this is balanced in and out correct?
-----------------------------------------------------------------------------------------------
The rest of the steps are distortion and meter stuff which I have under control.
