1

MP573 Microphone preamplifier / Re: Second hand MP573 with -6dB level drop

« on: April 21, 2026, 10:16:03 AM »

Yes, at all gain and output positions

2

MP573 Microphone preamplifier / Second hand MP573 with -6dB level drop

« on: April 20, 2026, 08:07:07 PM »

Hi!!

Im just received a second hand MP573 (I have other three), and after compare them with "Smaart", the last one has a -6dB drop across the entire frequency spectrum, and that difference remains even when modifying the gain or the output potentiometer.

Where should I start looking for the point of failure?

Thanks in advance
Regards 
Sergio

3

EQ573 Equaliser / Re: Frecuency response EQ573-II when active

« on: May 10, 2023, 11:05:26 AM »

Sorry, is true that the attenuation not shown. Is about -1dB aprox, and the two units have the same behaviour. All EQ bands works well and after your comments I asume they are ok. 

Thanks!!!! 

4

MP573 Microphone preamplifier / Re: Calibration

« on: May 09, 2023, 02:20:30 PM »

So .. I finally managed to try this fix and it works perfectly.
Very happy my trim knobs on the stereo bus are matched!

One more question: can I do the same with my 5.99 and 5.12?
What resistor do I look for.

Thanks!

Hi Bert! What value do you use finally? I understand you changed the resistor in one preamp only, did you?
Thanks!!!

5

EQ573 Equaliser / Frecuency response EQ573-II when active

« on: May 08, 2023, 10:17:25 AM »

Hi!!!

Im just build two EQ573-II and they work and sound amazing!!!

The only thing I don't know if it is normal, is small changes in the frequency response when the EQ is ON, but not EQ is applying.
Also, when I select some LF frequency, the signal level falls off.

You can see this in the attached images

Thanks!!!

6

MP573 Microphone preamplifier / Re: Mp573 Volume trim to zero

« on: January 24, 2023, 01:16:33 PM »

Thanks JeanPierre

7

MP573 Microphone preamplifier / Re: Mp573 Volume trim to zero

« on: January 18, 2023, 03:04:51 PM »

Hi!

I'm interesting in this possible mod.
Which behaviour would have the volume trim if change the resistor for a wire? Zero attenuation in "+10" position and maximum attenuation in "-10" position?

Thanks in advance!!

8

CP5176 FET compressor / Need help with 2:1 to 20:1 ratios

« on: April 10, 2022, 01:31:07 PM »

Hi!!

I have a CP5176 compressor, but the ratios 2:1 to 20:1 not work. The signal seems pass without compression. 
The AC levels on TP3 are 0V except for SLAM ratio that is 6.6V.
All the other levels are OK.

When I meausured the V+/V- voltage, maybe did some cortocircuit with the tester pin and some smoke came out of one of C31/C32 capacitors. Could this be the cause of this problem?

Thanks in advance!!!
Regards