903-51X Comp / Limit

[Claudio]

Hi Volker,

habe heute etwas Zeit gefunden, das Modul fertig zu bauen. Bevor ich es anschließe, ein kurzer Sicherheitscheck: Ist die Brücke so nun richtig (siehe Anhang), wenn ich den 903-51x in einem VPR-Rack benutzen will?

Danke
Claudio

 

[[silent:arts]]

Perfect!

 

[Claudio]

Ok, thanks!

But here’s another problem: When I mount the meter board to the main PCB, the distance is too high and the LEDs tower over the bracket. Seems like the connector pins are too long. See picture.

Yes, I know, I soldered the socket to the meter board and the pins to the main PCB and not the other way around as in your pics. But this shouldn’t make a difference, since the distance between the two PCBs would still be the same.

So what’s wrong here? Could this be another packaging mistake and the 2 x 5 socket or pins are simply too large?

 

[[silent:arts]]

No packaging mistake. You need to shorten the header.

 

[Claudio]

But it has these plastic stops at each end that define the distance. Where exactly should I cut, and how much? Do you happen to have a picture of it?

 

[[silent:arts]]

Cut it away.

 

[Claudio]

After a long break, I finally finished my 903-51X build in five minutes today. Sounds great, quite aggressive compression, though. I might have to look into calibration next. Thanks, Volker, for all your support and patience with my newbie questions!

Now I’m left with another huge problem: my lunchbox is full now...

 

[kante1603]

There's only one solution,isn't it  8)  ?


Best regards,


Udo.

 

[Claudio]

There's only one solution,isn't it  8)  ?

For the lunchbox you mean? Sure. Six slots just ain’t enough.

 

[kante1603]

For the lunchbox you mean? Sure. Six slots just ain’t enough.

Yep!

 

[Mulmany]

Was a calibration procedure ever nailed down? Over the initial voltage calibration, I mean.

 

[[silent:arts]]

Was a calibration procedure ever nailed down? Over the initial voltage calibration, I mean.

Sorry if I missed mailing one to you:

Output Gain Calibration
1. Set the controls to the following positions:
- Unit not set to BYPASS
- THRESHOLD control set to 0
- RATIO set to 1:1
- GAIN set to 0dB
2. Set your signal generator to 0 dBu at 1kHz
3. Adjust GAIN CAL R12 so that the level at the output is 0 dBu

Output Offset Calibration
1. Mute your signal generator
2. Measure DC with your voltmeter at the left leg of R28
3. Adjust OUPUT OFFSET TRIM R22 to nearest 0V DC

Infinite LED Adjustment
1. Set your Ratio Potentiometer (R56) to Position INF:1
2. Adjust INF LED CAL R60 to switch between on and off at that position

INF CAL Adjustment
1. turn INF CAL R57 full counterclockwise

THRESH CAL Adjustment
1. Measure DC with your voltmeter at the upper Leg of R50
2. Adjust THRESH CAL R49 to nearest +10V DC

OFFSET TRIM Adjustment
1. Measure DC with your voltmeter at the upper Leg of R53
2. Adjust OFFSET TRIM R54 to nearest 0V DC

RMS Symmetry Adjustment
1. Set your signal generator to 0 dBu at 100Hz
2. Monitor IC2 Pin1
3a. Adjust RMS SYM TRIM R40 for best RMS symmetry (equal amplitude peaks of the waveform)
or
3b. Adjust to measure 50mV with your voltmeter at IC2 Pin1

 

[Mulmany]

Sorry if I missed mailing one to you:

Output Gain Calibration
1. Set the controls to the following positions:
- Unit not set to BYPASS
- THRESHOLD control set to 0
- RATIO set to 1:1
- GAIN set to 0dB
2. Set your signal generator to 0 dBu at 1kHz
3. Adjust GAIN CAL R12 so that the level at the output is 0 dBu

Output Offset Calibration
1. Mute your signal generator
2. Measure DC with your voltmeter at the left leg of R28
3. Adjust OUPUT OFFSET TRIM R22 to nearest 0V DC

Infinite LED Adjustment
1. Set your Ratio Potentiometer (R56) to Position INF:1
2. Adjust INF LED CAL R60 to switch between on and off at that position

INF CAL Adjustment
1. turn INF CAL R57 full counterclockwise

THRESH CAL Adjustment
1. Measure DC with your voltmeter at the upper Leg of R50
2. Adjust THRESH CAL R49 to nearest +10V DC

OFFSET TRIM Adjustment
1. Measure DC with your voltmeter at the upper Leg of R53
2. Adjust OFFSET TRIM R54 to nearest 0V DC

RMS Symmetry Adjustment
1. Set your signal generator to 0 dBu at 100Hz
2. Monitor IC2 Pin1
3a. Adjust RMS SYM TRIM R40 for best RMS symmetry (equal amplitude peaks of the waveform)
or
3b. Adjust to measure 50mV with your voltmeter at IC2 Pin1

Thanks.