cp-251/vx-351 rackmount kit: power

[triptolemos]

It would be nice to power my cp-251 from my vx-351 with the cable included in the rackmount kit. However I understand this causes noise issues? Is it better to power the cp-251 with the seperate psu?

[Unfiltered]

i had the same problem. when I patch into the cp, it causes a high pitched ringing for some reason, but I have not tried it with seperate psu, so I am not sure if thats the cause. try it both ways, without screws in.

[ThiloO]

I'm glad I found this post. As a matter of fact, I haven't even gotten to the noise issue yet. I just recently got my rackmount kit.
Can anyone desribe to me where exactly the cable-harness goes in each the cp-251 and the vx-351.
Replies are greatly appreciated.

[kimbo]

The VX-351 connects directly from the parellel (21-pin) port in your Voyager to the parallel port on the front panel of the VX-351.
All CV expansion connections and necessary power is provided from the Voyager via this lead.
The CP-251 is a totally independant module in the fact that it requires a power supply other than from the Voyager.
By trying to 'daisy-chain' the power from the Voyager to both modules will undoubtably cause a ground loop thus generating all sorts of problems.

[ThiloO]

@ kimbo: But then why is specifially mentioned in the rackmount-kit product-description that the kit comes with a cable-harness which
is used to connect the cp--251's power via the vx-351.
To finish your thought .... Is Moog.Inc unaware of the groundloop problem? (I can hardly believe that)

[EMwhite]

Can anyone desribe to me where exactly the cable-harness goes in each the cp-251 and the vx-351.
Replies are greatly appreciated.

It's a 2 lead foot or so length cable with with board connectors. Looks alot like this:

IMG_2155.jpg

[ThiloO]

@ EMwhite:
Thanks for your reply. I already got the cable. But my question is: Where do both ends go exactly?

[glide]

By trying to 'daisy-chain' the power from the Voyager to both modules will undoubtably cause a ground loop thus generating all sorts of problems.

Hi,

no ground loop here with the very same configuration.
But the rack I use for both modules does not contain anything else connected to the Voyager (for instance, an unbalanced audio cable).

Cheers

[ThiloO]

@glide:
Good to hear that you don't have a ground loop. That makes me more confident in using the cable harness.
Still my question remains unanswered: Where do both ends of the cable-harness go exactly in the 2 devices ?

[pinkles]

Hi everyone. I'm glad I came across this thread, as I think am experiencing this ground loop problem. Since I have racked my vx with my cp I hear a high pitch hum, not unlike something you'd hear from a cheap tv. I noticed last week and ordered a new db25 cable thinking that the cable I bought off ebay might be bad. Got the new cable this morning and the problem persists.

Are there any solutions to this? Aside from removing the jumper and running the cp 251 from the wall wart? Is there a way to run the cp 251 from the wall wart while its still in the rack without leaving a rack space above it?

Any help would be very much appreciated. I just dropped over $500 on the cp 251, rack stand and rack mount for the cp/vx and three of my foogers.

[latigid on]

Hi, you'll find the CP-251 can be powered from the "top" or the "back" (oriented as when the unit is racked).

So no empty space needed. The daisy chain is not recommended, but it clearly works for some.

HTH,