pico se ll calibration procedure

Hi  lads/gals,

Do anyone of you, know how  the calibration procedure ,for the pico is done correctly .

pico se ll  auto/peak/rms mode plus A/R board, any help would be appreciated


Cheers

skal

It's been a while for me, but you have the original SE Ii boards plus AR board?

If so, stuff them correctly and there's not much calibration needed.

Only AGC distortion for as low as possible (use 1k frequency and adjust 2nd/3rd harmonics looking at scope). 

And, IIRC, overall gain of the AGC when not compressing. That's it.

When using  Roger's original AR board, I think it simply replaced one resistor (or a jumper, can't remember) on the main board.

Hi  Script,

so whats the detection pot for

skal

Am not at home right now and might be confounding with number of trimmers in different comp.

How many trimmers are on the board?

If its only one trimmer per channel, then those are for optimizing the harmonic distortion of the gain cells. Set for lowest distortion. Although some might deliberately set for higher harmonics. Same left and right.

If it's two trimmers per channel, the second one is for adjusting the volume fed into the gain cell, placed before THAT AGC chip input pin.

Script said:

If it's two trimmers per channel, the second one is for adjusting the volume fed into the gain cell, placed before THAT AGC chip input pin.

Click to expand...

yeah thats the one , so whats the procedure for setting that trimmer then.

cheers
skal

Script said:

If it's two trimmers per channel, the second one is for adjusting the volume fed into the gain cell, placed before THAT AGC chip input pin.

Click to expand...

According to R. Foote's original schemo, it is in the RMS detector input, so it would change/adjust the threshold setting.

skal1 said:

yeah thats the one , so whats the procedure for setting that trimmer then.

Click to expand...

It's left to your appreciation and somewhat depends on the nominal level and your comfort zone.

Calibration best done in RMS mode.

Set RMS In trimmer for equal threshold levels left and right.

Adjust 2nd order harmonics to the same level but not lower than your soundcard, for example, when using software signal generator -- for lowest distortion. Use 1k frequency,  or 100k or both. Then set for lowest 2k /200k.