2. amps-preamps
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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
erik_squires
16,676 posts
 
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

wolf_garcia
6,769 posts
 
I'm still tense from being told to relax.
aberyclark
1,410 posts
 
George,
besides having your speakers blown, how did you like the sound of the PL pre with your Bryston?
inna
7,923 posts
 
Either Ralph made a mistake regarding Bryston or something much more interesting is going on.
Wolf, get tense!
atmasphere's avatar
atmasphere
12,103 posts
 
The Bryston amps, as well as many other high end amps, DO NOT
have DC output protection.
Usually a relay is required for DC protection, but it can be implemented by other means such as crowbar circuit (which is a means of shorting out the power supply of the amp if the DC circuit is triggered).

From the STEREOPHILE review:
https://www.stereophile.com/solidpoweramps/108bry/index.html
Because the 28B-SST's components and circuits are rugged, the protection-circuit parameters are not as restrictive as are found in other amplifiers. Even so, the protection circuit is designed to handle most fault conditions, including shorts and DC offset.
It would not surprise me to find out that the above comment is actually false; that would not be a first for Stereophile.  Calls to Bryston here in the US and Canada did not get me to the bottom of it. I'll try again on Monday.
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