DB54 - 2254 style compressor {update 22.10.19}

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Hi Everyone,

I replaced all of the transistors that I put in wrong in all 3 boards, and now I can set the BA283 bias calibration to 2.3VDC.

I could not successfully perform the next calibration (step 6 - unity gain calibration). I fed in the 1kHz signal and recorded the output signal. Here are my results:

1) The recorded signal is exactly the same as the input signal when the 'Compress" switch is in the On position; turning any of the knobs does not have any effect on the recorded signal..

2) When the "Compress" switch is in the Off position, I only get a recorded signal if the Gain knob is turned all the way up, but the signal is very low in volume.

3) The meter is not moving at all.

Any ideas on how I can troubleshoot this?
 
Turning the VR3 Gain Set, as step 6 of the instructions say, have absolutely no effect.

Turning the VR2 Threshold Set, as step 7 of the instructions say, have absolutely no effect.
 
Studying the schematic for BA191 I saw that I had TR4 installed wrong. I used the schematic to determine the proper orientation, but no change in operation.
 
I also found that TR5 on BA185 was installed incorrectly, so I put it in properly but still no change.

I was wondering, if I installed transistors incorrectly and applied voltage, does that ruin them?
 
Where did you grab the schematic for the BA185? The one in the technical docs forum looked like it didn't quite match the BOM, and I sort of feel like I missed something. I find it incredibly frustrating when a project like this doesn't come with a schematic of its own, especially when it says right in the project docs that it isn't a 1:1 clone.
 
Hi Everyone,

I replaced all of the transistors that I put in wrong in all 3 boards, and now I can set the BA283 bias calibration to 2.3VDC.

I could not successfully perform the next calibration (step 6 - unity gain calibration). I fed in the 1kHz signal and recorded the output signal. Here are my results:

1) The recorded signal is exactly the same as the input signal when the 'Compress" switch is in the On position; turning any of the knobs does not have any effect on the recorded signal..

2) When the "Compress" switch is in the Off position, I only get a recorded signal if the Gain knob is turned all the way up, but the signal is very low in volume.

3) The meter is not moving at all.

Any ideas on how I can troubleshoot this?
Hi MoJo when the compress switch is off (Up Position on my unit) the gain make up shouldn‘t have an effect. Level should be roughly the same. When you switch in the compression chain (toggle switch in the down position on my unit) the Gain make up should work then. could it be that you are mixing it up (on/off position)? would make more sense ?
 

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