PrimaLuna Dialogue Premium Preamplifier. DESTROYS SPEAKERS!!

Thank you. 

George- Unfortunately, it's possible/probable that some of what you have dealt with is caused by living on the bleeding edge.  Sometimes, extracting that last bit of performance comes at the expense of some reliability.  One of my engineering colleagues once told me that there are three variables in every project: cost, quality/performance, and schedule.  When you specify two of them, they dictate the third.  Although I have absolutely zero technical knowledge of circuitry and electrical engineering, of all of the supposed experts that have commented so far, I find Almarg's analysis to be persuasive.  And that leaves aside the circumstantial evidence that the same part failed in the same unusual way, twice in a row.  That, to me, strongly suggests some kind of unusual interaction among the component parts of the system. 

Anyways, the retailer, distributors, and manufacturers involved all stepped up.  You've been made whole.  It's the very rare manufacturer of anything at all that provides warranty coverage for consequential damages. In my recollection, virtually every warranty I've ever taken the time to read expressly rules out such coverage.  You're out some time to replace some circuit boards.  If a fuse blows, do you expect someone to compensate you for the time it takes to replace it?  The other option, I imagine, was for you to pay for shipping the speaker back to ML.  I think you lucked out by having a manufacturer willing to take a chance that you would be able to make that swap yourself without doing other damage, which based on all of the available evidence, you would have then blamed on ML. 

Has anyone actually validated the OP's failures are as stated? Does anyone have eyes on a bad cap?

Best,

E

At the end of the day it will be hilarious if the actual issue  was the amps. I'm not sure the OP can even tell if he had DC or not.

Has anyone else validated his claimed root cause analysis?

Best,

E

"If, the pre amp, puts out DC, the amp will amplify it, and send out to the speakers, which is what happened in this case."


WOW, It blows me away to hear that multi thousand dollar amps do this.
So no protection circuitry, built in? They degrade sound huh? I’m not so sure this is true.

This is why I buy MAC amplifiers,
My McIntosh MC352 (which sounds awesome) would never let DC get to my speakers!
This is just one of Six circuits that Mac puts into a lot of their amps.

" DC Failure protection. In the rare event of an output circuit failure, ANY DC current that appears in the output is shunted to ground by the autoformer, protecting the speakers from damage"

I hope the OP can move forward and still get some enjoyment from his system in the future.



Matt M