2. amps-preamps
  3. 131501-88991

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
almarg's avatar
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almarg
9,670 posts
 
UpscaleAudio9-23-2017
It was a small cap in the right channel, NOT the Mundorf coupling caps. We suspect an oscillation as my service tech here works for another brand that was faced with the same problem.
Kevin, thanks for providing us with the comprehensive additional background and info in your response.

An oscillation, albeit perhaps at a very low frequency, seems to me to be much more probable than the previous assertions that the preamp was outputting DC. Given what I said in my previous post about the Bryston amp likely having coupling capacitors at its inputs, and even more so if the Mundorf caps you are referring to are the preamp’s output coupling caps.

A post by Atmasphere some years ago in this thread, concerning a low frequency oscillation problem that occurred with a preamp made by a different well-regarded manufacturer, may be helpful to your tech. I’ll quote an excerpt that may be relevant. Again, this pertains to a different manufacturer’s preamp:
Atmasphere 8-3-2012
The problem is that there is a power supply instability in the preamp. The output coupling cap, when driving a 100K load, represented a frequency pole that was lower than the frequency pole in the preamp’s power supply.

The result is low frequency instability. With many amps this may not manifest with anything, especially if the amp does not have good LF bandwidth, but I think the interaction occurred due to the fact that you do have enough bandwidth in the amp and the power of the amplifier was able to mess with the AC line voltage, which in turn exacerbated the LF instability of the preamp.

So lowering the input impedance of the amplifier solved the problem by knocking off an octave of LF bandwidth.
In any event, even if that kind of phenomenon is not what has occurred in the present situation it serves to illustrate that no matter how expert and thorough the designer is there is always the possibility that relatively unique system applications can bring out a problem that wouldn’t appear in most other applications. And the uncommonly high power capability of the OP’s amp, together with its exceptionally extended low frequency bandwidth, and perhaps also the characteristics of his speakers, would seem to make his situation uncommon at best. As well as increasing the likelihood that the phenomenon Ralph (Atmasphere) described in the thread I referenced is applicable.

For all we know, in the absence of a schematic and a detailed analysis, **even if** the capacitor has failed in some other systems it might not have caused any issues, not even sonic issues.

Regards,
-- Al

ebm
9,311 posts
 
Time to give it a rest and move on. Good luck though.
axememan's avatar
axememan
279 posts
 
Primaluna Prologue 5..beautifully built..zero issues..bought used..can recommend Primaluna 100%.I liked Mr Deals response...contacted the customer while on vacation in Eurpoe.That seems like he does care..maybe they can post a statement on site warning of possible issues?
inna
7,296 posts
 
Still, it's all better than when the fighter jets crash and we are not told the truth. At least 50% of cases its something like bad capacitor,sometimes Chinese. Yeah, let's move on.
larryi
4,085 posts
 

So, a bit more of the story has been clarified.  Given that the OP is NOT out money on the damage done to the ML, but had to spend a lot of time dealing with the problem, what does he expect from Kevin Deal?  Does he expect Kevin to come to his place and rake leaves for the hours lost? 

I can understand not being happy with the product.  Even if it is a rare happenstance, if you are the unfortunate person, it is understandable that the brand is, for the victim of circumstances, anathema.

This sort of failure, whether it is caused by a bad lot of a certain part (this happens with the best of gear), or some kind of unexpected incompatibility, does not necessarily implicate the product as poorly designed or shoddily built. 

It makes even less sense for someone to point to a single problem as evidence that products of a whole nation or region of the world should be avoided.  When the Chinese build for a foreign company, the product is as well-built as is specified by the customer.  The customer also specifies the parts used.  The customer has some responsibility to oversee how their product is built.  If the Chinese company does not live up to the bargain, it is the customer's responsibility to change manufacturer.  Cheap build is what some buyers want, and what they get, but that is not the case with all Chinese gear.  Note that China is FAR from being the lowest cost manufacturer these days; they compete because they can deliver what the buyer needs in many ways: ease of doing business, flexibility in making design changes, etc.

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