Calibrating AML ez1073pre Confusion

[funkymonksf]

Hi y’all,

I’ve been unable, despite deep diving all over, to find a way to do the following: (NOTE: I’m referring to step 4, gain)

ez1073pre Calibration / Setup
1 ] Before powering up the module, turn the “Bias Adjust” trimmer R58 fully counter-clockwise (about 10 turns)
2 ] Power up module, measure the DC voltage between bias test points TP1 & TP2 [It should typically measure about 40-50 mV (after relay clicks)]
3 ] Slowly turn the “Bias Adjust” trimmer R58 clockwise until the DC voltage now measures 90mV
4 ] Apply a signal of -40dBu to the input and then turn front panel gain control up to +60dB
5 ] Ensure that the front panel brass coloured “Trim” control pot is turned fully clockwise
6 ] Measure the output signal, and adjust the “Gain Adjust” trimmer R70 until output measures +20dBu

I have a Focusrite 18i20 via Ableton Lite. I know ableton’s operator would help generate the signal, but I don’t want to spend $99.

What do you use and how to generate and measure said signal?

Much appreciated,

Brice

 

[oongbac]

REW has a generator with dBu option but you need to calibrate that with a true rms multimeter. I’m using UNI-T one. Because it is quite cheap. And with a true rms multimeter and simple dBu to volt calculator on the internet you can simply measure voltage between pin 1 and pin 2 of XLR.

 

[oongbac]

REW has a generator with dBu option but you need to calibrate that with a true rms multimeter. I’m using UNI-T one. Because it is quite cheap. And with a true rms multimeter and simple dBu to volt calculator on the internet you can simply measure voltage between pin 1 and pin 2 of XLR.

Oh I’m sorry. You should measure voltage between pin 2 and 3! Not pin 1 and 2.