[wreutz]

Hi,

I have a very strange problem.
My setup is a R6 Rack with MP5.66, EQ573, CP5176, MP573, mEQ, LA502.
Today when routing a bass track through the LA502 I did get a very very quiet signal, if I put the output to max its distorted and there is complete lack of bass and more high frequencies than the original.
I checked with the CP5176, the signal is quiet but only a bit but there is complete lack of bass.
I checked through the EQ573 and it sounds plausible.
If I route through CP5176 and bypass the sound is normal!

Now the very strange thing:
I have a second Rack Fredenstein Bento 6S.
If I put the CP5176 into that rack it sounds and behaves as expected and normal!!!

I checked the +/-16 V and +48V of the Neve Rack and it has correct values. I removed all other modules, changed slots, measured with bypass and without, power seems ok.
I normally use SUB-D connectors of the Rack but triple checked to use XLR ...


Anyone any idea what could cause this strange behaviour??
A power supply should not affect the audio signal ...

any help appreciated
Wolfgang

[JPK]

there is complete lack of bass and more high frequencies than the original.
This sounds like you are only connecting one phase of the balanced signal output. The transformer coupled outputs are floating and need both phases to be connected.
Check your connecting cables and make sure both phases are connected.

[wreutz]

thank you for this hint!

As I did not change the cabling from the patchbay to the 500 rack and while testing I used different slots and cables I have to check the inner guts of the rack for bad contacts or solder joints ...

But now I have idea where to look, thanks!