Help? Why Classe CAM-350s going into protection mo

What I thought would be an audio dream has turned into an audio nightmare.

I finally was able to purchase a pair of Revel Studios this past Sunday. The System:

Meridian 508.24 cd player
ARC Ref 2 Mk II preamplifier
Classe CAM-350 monoblocks
Revel Studios

I have the Meridian connected to the ARC via some Synergistic Research balanced, the ARC to the Classes via some generic Radio Shack single-ended and the Classes to the Revels via Kimber Bi-Focal XL cables.

The reason for the Rat Shack cable is that my previous speakers were just run-of-the-mill Klipsch bookshelf 2-ways. I lived in NYC for 11 years and couldn't really justify good speakers in my small apartment. I've slowly accumulated the pieces over the years with the Studios the last piece of the puzzle.

More background: I moved to Chicago a year ago during which time the Classes were boxed. They had not been used until Sunday (almost 13 months). I'm living in an 8 unit condo with 5 units occupied.

The Problem: After times ranging from 3 minutes to an hour, the speakers emit a short "zzz" (maybe one second long) then a "pop" then BOTH amps go into protection mode (flashing green light). I unplug the amps and take a look at the fuses. They look OK to me, but I guess I'm not sure what a blown fuse would look like. After waiting 30 minutes, I plug the amps back in, turn them on and start listening again. Two more times the same thing happened after various lengths of listening time.

Despite the Studios having a low 87 db sensitivity, the speakers sound loud and my volume is not going past 8 o'clock (this could be a related issue). Only during softer passages have I gone to 10 o'clock. In fact, as I did with the Klipschs, I used Rothwell attenuators to lower the noise floor (I hate hiss). This never was a problem with the Klipschs. The Classes "blew up" once with the attenuators and the Studios so I thought that might have been the cause, but the same problem occurred after the attenuators were removed.

Explanations?: I'm no expert so some of these suggestions might be outright dumb. Is it the Radio Shack interconnect? Both runs are either 6 or 8 feet (can't remember). Could there be a short? It's very odd that BOTH amps are experiencing the same problem which would imply shorts in both wires.

Is there a problem with the preamp? The ASC wasn't used for 13 months either. Before reinserting the tubes, I had them checked out by an ARC dealer who pronounced them fine.

Could there be an issue with my unit or building? For example, when the fridge sets in or turns off, is there some sort of "surge" causing the amps to go into protection mode? Is someone in another unit using some sort of appliance that could cause a "surge"?

To be so close and so far to audio nirvana has really upset me. As the amps are extremely heavy, I'd rather not have to box and ship them back to Classe. The again, they might not be at fault. I'm hoping some of you guys might have experienced this before and can recommend a simple and straightforward solution.


I would call Classe and tell them just what you said in your post.
You could also call Revel.
Thats were I would start.
Good luck.
Disconnect the inputs to the amps and see if they still shut down. If not, it's the ARC (or the interconnects). If so, disconnect the Studios from the amps and see if they still shut down. If not, it's the Revels (or the speaker cable). If they shut down on their own, well..............

I would suspect the ARC since both monoblocks switch off. Kal's suggestions are right on. Keep us posted.

At the risk of sounding ignorant, I thought disconnecting anything while still powered on or even plugged in was dangerous. Kal, are you saying to disconnect the interconnect from the ARC to the amps before the amps are turned on or after? Also, are amps designed to shut down if they are not connected to either a pre or speakers? Thanks.
Turned off when connecting and disconnecting....good advice from Kal

No. I did not say to do any of the connecting/disconnecting while the units were on. I didn't say to do it when they were off because I was presuming that reasonable users would know this.

Why would the amps be designed to shut down if they didn't have inputs or outputs?

Sounds like a tube is going in the preamp....

Do what has been suggested turn everything off and disconnect the preamp from the amps and just turn the amps on and see if they go into standy or safety after heating up.

Borrow a another solid state preamp, or use the preamps out of a reciever if you have one.
If both amps shut down simultaneously it almost has to be upstream from them. I'd suspect the preamp. Beg, steal, borrow or by another to swap in. Or get anything with an adjustable line out to hook to the amps. A portable discman or ipod will suffice for test. Good luck.
There's nothing wrong with the amps. They're reacting to something from the preamp.
Preamp.Sounds like a tube issue.Pull top cover on the preamp(if you feel that you are capable)then turn everything on and watch the tubes for any sign of a tube glowing blue or shorting.That is where I would start but be carefull.

Thanks for all of your responses.

I use a Melos SHA-1 as a headphone amp and swapped it in for the ARC. Last night in about 3 hours of use, there were no audible issues and the amps never shut down as before. I will now have the ARC checked out. Thanks and I'll keep you all posted.