Classe CA-400 amp trips

BAT preamps have a rep for sometimes outputting small amounts of dc, that could be what's happening. DC would cause your amps protection circuit to kick in. Get a multimeter and measure the dc output of you preamp. It's not very hard to do, I can't remember the ok range for dc, but I'm sure someone on here does. Sean?

I agree with Jond's assessment i.e. that the BAT preamp is probably the culprit. If you look in the Agon archives, you'll find some similar threads with similar responses. Some of this has to do with the design of the product itself, not so much DC voltage. I just discussed this with Victor Khomenko of BAT over at AA in this thread here.

Out of curiosity, are you using the pre / amp in RCA or XLR mode? Switching to XLR's may resolve your problem. You can try this relatively economically by purchasing cabling at Guitar Center, Sam Ash, etc... or any other musical instrument vendor. If this takes care of the problem, i would contact BAT to see how this problem could be rectified. They are a reputable company and should stand behind their product.

As a side note, those interested in high bias designs may want to check out a thread at AA pertaining to circuit design / bias levels / current draw / circuit efficiency. Some of the same participants in the thread above ( myself, Victor of BAT and Brian of VMPS ) contribute contrasting points of view there also : ) Sean
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I have a Classe CA 400 and had the same problem when using a Melos SHA Gold preamp. The preamp was sent to a local guy who found that it was passing DC. He modified the SHA Gold and it solved the problem. Unfortunately this was after the amp went belly up and had to make a trip to Montreal. I would advise you to take action before breaking the amp.
Good luck. John

Solidly, I'm using all XLR connections - NO RCA's.
I acquired a Monster Power Center HTS5100 and I thought it's causing the problem when my house's A/C or ref. current goes on.
Obviously, that does it for another expenditure.
As far as the DC issue, what can I do now, besides sending my BAT back to the manufacturer?

this is going to sound strage but this happen to me once (i have classe cam monos and a bat vk30) and it occured when i was wearing slippers that cause static electricity.

i touched the cd player and it caused the pre to shut down and turned back on and the amps to go into protection..

sounds strange but it does happen with a build up of static electricity..