PrimaLuna Dialogue Premium Preamplifier. DESTROYS SPEAKERS!!



A few months ago, bought TWO of the above mentioned preamps. ( I have 2 stereo systems)
Within 6 weeks of the purchase, the power supply of my speakers burns out!
I purchase and replace the power supply.
Three days later, the second newly replaced power supply is burnt out!
After much investigative work and heartache, I discover that the Pre amp is the problem.
It is defective and puts out DC. which burns out speakers.
After, testing the second unit, I find that it is defective as well, EXACTLY the same problem.
I return the units to my dealer, who returns them to Prima Lune.

I received a phone call from a Mr. Kevin Deal, big cheese at PrimaLuna.
Told me that the capacitors, on BOTH units had failed and the units were putting out DC.
He even THANKED me, for being a guinea pig, and discovering the flaw in his units.

He offered me a pair of tubes, as "compensation" for my troubles!! What a joker!!

WOW, a pair of tubes for blowing my $30,000. speakers!!

The height of arrogance and total disregard for the consumer of his product.
To all audiophiles, do yourself a favour, STAY AWAY for this brand, unless you want your speakers cooked.

TOTAL lack of quality control, MADE IN CHINA junk, what more needs to be said.


Mr. Deal, WAKE UP, and STOP selling defective products!!


If, you are using PrimaLuna, and your speakers fail, check the amp or pre amp.

George


Montreal, Quebec, Canada.
thorloki

Showing 11 responses by erik_squires

@atmasphere and that's why I am confused.

The OP said specifically it was DC and that he damaged his speaker, not his amp.

<< shrug >>

Not a big deal.

Best,

E
For clarity, this is not a large coupling cap that failed in George's preamp.  It's a high-frequency snubber, which is why the suspicion about outside causes.  

So...the amp got DC not through the coupling cap but through some shunting circuit between signal and ground???

This makes even less sense. I don't doubt you, @upscaleaudio  I'm just more and more confused. If a snubber failed... I'd more expect HF oscillation to occur, which definitely could be damaging. << shrug >> but without seeing some sort of design, I certainly cannot be an arm-chair critic. I'm just expressing my cross eyed lack of understanding.

Best,

E


Don't want to hijack the thread, but I have to agree. DC input protection should be de rigeur for most amps, especially one with such high current you could weld with it.

Also VERY surprised a professional grade amp would not include this.

By the way, my ICEPower amps include all sorts of protection circuits and sound great. :D

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

Best,

E
By the way, just in general, calling to boycott all products from a certain country or region based on two samples is not really something I can support.

It's not the country so much as paying a fair wage and maintaining consistent quality controls that matters.

Anyone who thinks US products are naturally OK just because they are made in America has never worked in food quality. Quality doesn't just happen. It takes effort.

Best,


E
HI @upscaleaudio  Thanks for your thorough reply.

Could you give me any specifics, even privately, as to the brand of capacitor that failed?

Best,

E
OP - Do you have any idea the brand of caps that failed?

As a speaker maker (hobby) I'm very much into capacitor brands, I'd be very curious if there was a failure in a Mundorf or SCR, especially if there were repeats.

Best,


E
I'm not sure how a DC servo circuit would degrade sound if properly implemented, so it is disappointing to hear Bryston does not incorporate them.

The worst case is of course capacitor coupled, but almost all tube preamps are anyway.

Adding sensors at the output to disconnect the speakers, inputs or even turn the whole amplifier off are quite worthwhile.

DC servo circuits operate below 10 Hz. A combination servo + disconnect should be required << shrug >> but hey, I don't own a large successful audio equipment company.

Best,

E

I have to say I am scratching my head at the description of the episode here, as well as the user. There are major pieces missing from the description.

According to Audiogon, this user has started two nearly identical threads, and never bought or sold anything since the account was started in 2016?

It is difficult to know whether to take the OP seriously or not. But let’s do.

AFAIK, like 99% of all tube preamps, the PL Dialogue is capacitor coupled. The Premium version used to use Solen / SCR tin caps and now has switched to Mundorf. Both premium brands with VERY good reliability. Solen / SCR is a MAJOR OEM manufacturer under various brands and has a rock solid reputation. Honestly would be shocked to discover their premium caps failed. Same with Mundorf.

Also from what I can tell, and could be wrong, PL is using obsessively large caps, in the 10uF range. The original CJ PV 10 used 2uF coupling caps. This in theory improves bass response, in practical terms is probably meaningless, but it’s not evidence of PL cutting corners at all.

Personally not a huge fan of the sound of either.... but I am 100% in the minority there. :)

My point, if what I believe to be true is true then the PL DL uses premium coupling caps that in terms of reliability are not easily improved upon.

Best,


E