MXL 2006 - Built from scratch - Very low output level

[forzasalva]

Hi folks,
I need your help.
I had a MXL 2006 modded with the Advanced Mod Kit by microphoneparts.com and a RK47.

Now I wanted to build a new one from scratch. I copied the PCB 1:1 and bought the parts of the advanced mod kit
and the parts that weren't touched by the mod. I used the MXL schematics here.
I soldered everything, biased the JFET and connected the microphone to my preamp
and the output level I'm getting is low. Compared to my older MXL 2006 the output is VERY low.
So what could be the problem, since I built it exactly like the original MXL 2006.
Every part, every trace and every cable.

I measured the polarization voltage on my DC-DC Converter board and it's only 29V.
On my older MXL 2006 it's 60V.
What could be the problem?

Best regards.
forzasalva

 

[RuudNL]

Hi Salvatore,

You mailed me already about this subject.
Could you give us the following voltages:

- The voltages on pin 2 and 3 of the XLR connector (referred to pin 1)
- The voltage on the junction of the collectors of the PNP transistors
- The voltages on both sides of the drain resistor
- The voltage on the source of the FET

With these voltages, it might be possible to diagnose what is wrong!