Opinions on VTL preamps

I have a 5.5 and a st150 that I was bi-amping with a classe ca 300 on the bottom driving b&w802n's .loved it so much thought i would get rid of the classe and got the phono 2.5tp and 225t90 mono blocks last week. I have had no problems until hooked up the mono blocks.put the st150 on the b out put for the rear and the monos on the A output for the front (bi-wireing).no need the classe bass is fine without no smear.About 1 minute into it the right side starts making a screaching noise then stops I dont know what it is but after another 10 sec it stops.So last night i have the system running for about 3 hours then shut down everything.Then this morning i go to power up the amps and then the screaching starts up on the right as usual for but now The st 150 starts in with the same crap only more anoying and louder like someone dragging a piece of metal across the blackboard. so I unplug the st 150 and hook up the ca 300 to see if maybe its the pre-amp. sound great except the 10 sec while the 225s are warming up. So I think its the st 150. I enjoy the sound of vtl,but hope its just a bad tube and not a transformer, i have spare tubes but i dont want to turn the thing on to try to bias until i figure out what that noise is.Anybody guess what is going on with the right mono and st150?

Just blew up the classe guess its the 5.5.

Found the problem, we had my listening chair delivered on friday. And My wife said they unpluged one of the speakers by accident, when I put it back i connected the neg to pos.So nothing wrong with the 5.5 ,classe or st150.still a little buzz for a couple seconds on the monos though,But once they are warmed up the sound great.

My impression of VTL is, they are EXTREMELY helpful by phone when something goes wrong, even if you bought it used & out of warrenty. But then, I've never had to send something in to them for out-of-warrenty repair work. I think a more important question here might be: how does VTL reliability & service compare with other tube mfg's--ARC, CJ, etc? Personally, I've started to calculate the shipping distance to the factory before buying any used gear......just my 2 cents.

Chayes...just swapping your positive and negative speaker inputs isn't gonna cause the problems your talking about, it wont cause ANY problem just polarity issues.
either you left something out or I misread it