Pass X-250 with REL sub


Hi all,
I have been advised that because of the design of the Pass Labs, I can only use the REL sub running from low level outputs. Something to do with the speaker terminals on the Pass not being or being a floating ground. Shame as I have no spare pre-outs.
Probably the least of my worries as the Pass has been plagued with problems from day one and my patience is at an end.
Does anyone have experience of running a Pass /REL combo from the high level outputs??
Do anyone have experience of grounding problems with the Pass which causes a PA system like buzzing thru the speakers.
It's not a grounding loop but a problem with the amp itself as I have been trying to tell Pass for six months.
Thanks Simon
simon74
Simon- you wrote-

"Probably the least of my worries as the Pass has been plagued with problems from day one and my patience is at an end".

I own the X-250 and a X2.5 Preamp, and have dealt with the Pass folks. I found them to be extremely customer focused and pleasant people, including Nelson himself.

If you feel in any way that your Pass X-250 is less than it should be, I recommend calling Peter or Nelson @ Pass Labs. I think they're great guys and will go the extra mile to help you.

Good Luck.
Thanks for that guys.
Seemingly because the Pass is not grounded at the speaker terminals (floating earth, I think is the term, something to do with the balanced design), it will upset things by the sub only being grounded to one terminal(or not as the case may be).
The REL manual mentions that in some cases the sub will hum if the power amp is switched off.
This was the case when I hooked the REL up to the PASS - I simply switched the sub off before putting the Pass in idle mode. It seemed to work just fine and caused no problems when the Pass was powered up.On taking advice I decided it was best to leave the sub out of the system, a shame as I am late to the fold but really think a sub opens out the midrange when used sparingly. I am not a bass freak but given the REL brings more to the table than the Pass, I wish I had known this in advance - think I'll stick with my Nu-Vista and the REL - I like an approximation of real music, not really interested in an initially 'hi-fi' sound which palls greatly on serious listening.
I used a rel Stentor with Pass Aleph 2 Monos. I connected the high level negative imput of the rel to one of the spare outputs from my cd player via Radio Shack RCA connector (Wadia 860 - no preamp). The 2 plus wires were connected to a plus on each monblock. Worked fine. Maybe that could work the 350s? Just grab a ground some where else in the system.

Terry
Hi Terry,
Thanks for that. It had occured to me to try this.
I'll check this out.
Simon