A real world high end meltdown- would love your input!

[marty]

Recently, I was contacted by good friend about an unfortunate incident he experienced in the wonderful world of high end audio. This is not a fabricated report. It really did happen as described. Here are the details:

Several years ago my friend sought to purchase a good stereo and sought my advice. I suggested he visited a local dealer who I knew would be reliable, and provide the outstanding guidance and service for which they are known. After some considerable auditioning, he purchased a Spectral preamp (not sure of the model), a Spectral 260 amp, interconnects and speaker cable, all by Spectral/MIT and Quad 2905 electrostats. All has been going splendidly until recently, when his 260 shut down, thus necessitating a visit to the Spectal factory for repair. The formal report from the Spectral service department a few weeks ago read “repeated crowbar shorting of Quad speakers caused damage to output stage”. The dealer has subsequently informed my friend that his speakers are not compatible with Spectral electronics. But more importantly, the resultant effect of this news is that my friend must now make a choice- should he keep the amp that he loves, or keep the speakers he loves? Apparently, he cannot have his cake and eat it too!

There are many questions that obviously come to mind. The most obvious to me is- why would his system work well for at least two years and then suddenly fail? Addressing that is probably purely speculative since even Spectral cannot seem to answer that question at the moment. But that’s not the question I am hoping forum members will weigh in on here. Rather, it’s the following. No matter what my friend chooses to do, it looks like he will obviously have to spend additional money for something he never thought he would have to do again; namely, pay for a high quality stereo rig that works and is reliable! So the question is, do any of you think my friend is entitled to be “made whole” and if so, by whom? After all, his only contribution to this incident was purchasing a system the dealer recommended, and which I think we can assume, Spectral sanctioned when it was purchased. Now, I can understand that there may have been a point at which Spectral honestly had no idea there was an issue with their electronics and Quad ESLs, and in fact this apparent incompatibility may have only be recently learned by Spectral (let’s assume this is the precedent case). The question, phrased slightly differently is: should the customer be expected to bear the expense that is now required to solve the situation? (He must either buy new speakers or a new amp!)

I’d love to learn what you all think. What would you say is the dealer’s responsibility in this instance? What is Spectral’s role? If it were you, what would be a satisfactory solution to the problem and who should bear the expense of paying for it?
Marty

 

[JackD201]

First thing I would do is complete the facts. What exactly does "repeated crowbar shorting of QUAD speakers" mean? Whatever it is, going by the word "shorting", it sounds like that is something that shouldn't happen at all. I would put the responsibility on QUAD if it is indeed found to be a loudspeaker fault. 2 years should be well within the warranty period. It is the dealer's duty to represent and support his client with regards to the warranty. As for QUAD (if it is their fault) picking up the tab for the Spectral repairs, take it if they offer it. I don't see anything that would let one compel them to do so as a part of regular business.

 

[esldude]

Have owned Quad ESL63's though not 989's. Apparently little has changed in the protection scheme. Quad had/has a protection scheme to prevent damage to the Quad speakers. It does indeed throw a short across the speaker. They do refer to it as a crowbar protection. Now this should only happen if the speaker is seeing more voltage than it should and the 260 is likely quite capable of that.

If I recall rightly they used a "sniffer circuit" to detect ionized air as this would occur when the panels were starting to arc over. There is the possibility that circuit is faulty and firing when it should not. There is the possibility some other source of interference is being picked up and passed onto the speakers by the Spectral equipment due to its very wide bandwidth (I believe current Spectral gear is flat to nearly 2 mhz). MIT cabling with its high frequency roll off normally would prevent that. But if of high enough frequency not to otherwise be noticed and of high enough level it could indeed rightly fire the protection even if the speakers weren't being played at an excessively high level. It could even be something odd like a freezer or AC kicking garbage through the power line and getting picked up when it switches on. So the protection might activate when the owner isn't even listening.

A key factor is whether the Spectral was damaged in one channel or both. Unlikely both crowbar circuits would go bad together. If it was both something is causing the Spectral to pass on some high voltage from interference or the owner is playing the speakers louder than he should. I don't know at what input voltage the 989's should crowbar the speakers. I would contact Quad and find out what it is (something in the back of my mind says I have read or been told it was 58 volts peak). The owner could also play his normal sounds and measure peak voltages seen. I also would think repetitive activation of the protection from whatever reason would be noticed by the owner.

It isn't quite as black and white as it may seem though it could turn out that way. Figuring this out is indeed where a good experienced dealer will earn his keep.

So should he keep amp or speakers? If he is playing them too loud, another big amp will suffer the same fate. If it is ultrasonic noise pickup he could filter it out unless the amp or pre-amp is picking it up internally (not through wiring) and sending it on. I would glance warily at the pre-amp as more likely than the amp. In fact switching to a lower bandwidth pre-amp might fix the issue. Another possibility is a DAC or other digital equipment connected. Some DACs have some very high idle tones that a Spectral would pickup. Have seen one with a high level 300khz idle tone. Had one once that put out a high level 1.1 mhz idle tone. When running a Spectral amp I simply used a 3 meter interconnect rather than one meter. The extra capacitance acted as enough of a filter to knock it down before it got to the Spectral input. Problem solved with a little extra interconnect (eventually remedied by getting another DAC).

 

[marty]

I edited my note- the speakers were 2905 Quads not 989s. But thanks for your input.

 

[tmallin]

ESLDude is correct about the Quad crowbar protection. Some amps may not like repeatedly feeding a dead short.

The sort of DC-to-light bandwidth Spectral uses makes the amps especially prone to damage from anything but just the right load. The strict recommendation of MIT cabling is to put a tuned filter on the outputs and inputs of the electronics to protect the equipment. I wonder if your friend might have swapped out some of the MIT cabling for something else for awhile?

For Quad speakers, Quad amps are quite the thing and are much less expensive than Spectral, of course. They are designed to drive Quad ESLs and are not bothered by the crowbar protection. The newer Platinum series of Quad amps is supposed to be a very nice match for the bit of overetching that Quads (especially the larger 989, 2905, 2912, etc.) have, letting through a bit more detail than prior Quad amps, but taming the sound just that teensy bit that makes the Quad speakers sound yet more realistic.

 

[microstrip]

The Quad ESL63 manual was very clear "Amplifiers that are not short circuit protected may be damaged and should not be used".

Considering the current high price of replacing an electrostatic panel, people should consider that replacing a few transistors and resistors are a cheap alternative ...

 

[Brian Walsh]

One has to wonder if occurrences like this, along with strict edicts by Spectral over the years that MIT cabling must be used with their electronics -- or else the warranty is voided -- might be a significant reason why they have so few dealers these days.

 

[JackD201]

The Quad ESL63 manual was very clear "Amplifiers that are not short circuit protected may be damaged and should not be used".

Considering the current high price of replacing an electrostatic panel, people should consider that replacing a few transistors and resistors are a cheap alternative …

Man, in light of this, what a pair of star crossed lovers! One isn't short protected and the other uses shorts to protect itself! Talk about irony.

 

[esldude]

One thing worth knowing is whether the owner of the Quads has noticed them going into protect mode and shutting down the sound?

 

[ack]

Man, in light of this, what a pair of star crossed lovers! One isn't short protected and the other uses shorts to protect itself! Talk about irony.

The Spectrals are short-protected, and I am quite certain they circuit would have kicked in every time necessary (the effect is almost instantaneous). But as Spectral said, "repeated" shorts will eventually kill the output devices, and that is only natural. I feel the dealer who suggested the combo should have known better, and the user should have said something well before. Personally, I would keep the Spectrals and mate them with Magicos for near-electrostatic attributes, but the choice is entirely personal.

 

[rbbert]

... a local dealer who I knew would be reliable, and provide the outstanding guidance and service for which they are known...

In light of the fact that this appears to be an obvious equipment mismatch, I have to wonder about this statement from the OP?

 

[mauidan]

Marty,

"The dealer has subsequently informed my friend that his speakers are not compatible with Spectral electronics."

I'd tell your friend to sell the Quad 2905 and look for a new dealer.

There's no distributor in the US and servicing can be a problem.

My friend with 2805s recently had a problem and was very lucky to get parts and find a local tech to install them.

 

[PeterA]

There is the possibility some other source of interference is being picked up and passed onto the speakers by the Spectral equipment due to its very wide bandwidth (I believe current Spectral gear is flat to nearly 2 mhz). MIT cabling with its high frequency roll off normally would prevent that.

This surprises me. MIT cables have always sounded very extended in the high frequencies to me, and anything but rolled off.

 

[esldude]

This surprises me. MIT cables have always sounded very extended in the high frequencies to me, and anything but rolled off.

Well when looking at equipment with near 2 mhz bandwidth the roll off is relative. Many interconnects may be flat to a megahertz or more. One rolling off at 200 khz due to extra capacitance or other effects won't sound any more rolled off. It would still be fully flat to 20 khz. But it will form a non-resonant first order filter for frequencies above 200 khz. Being down some 20 db at 2 mhz.

While the above numbers are simply examples the MIT products function something like this forming an ultrasonic first order roll off which in the case of Spectral gear is protective of oscillations or other undesired response at higher frequencies.

Of course all of this may be irrelevant. It could be the Quad owner was just playing them too loud. High frequencies, and wide bandwidth may have nothing to do with it.

 

[ack]

Well when looking at equipment with near 2 mhz bandwidth the roll off is relative. Many interconnects may be flat to a megahertz or more.

I would agree, it's all relative. Older MIT cables that Stereophile had measured started rolling off at ~800kHz, if I recall correctly.

 

[Garth]

...

 

[Ronm1]

If it was me I would think the dealer owed me on this a very large discount on new speakers or amps like half price or better. If not I would find a new dealer. A good dealer is a great asset .

Without question. They dropped the ball. IMHO too! That's the necessary part of a good B&M with hi-end.

 

[thedudeabides]

If the dealer sold the electronics and speakers to the client, the dealer should be fully responsible for any mismatch / replacement issues.