CECE
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Audio Research $10K amp
quadlover
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audio research's response raised my curiosity. if i understand it correctly, they infer a bad tube. if this is correct, let audio research replace the tubes and let john retest the unit. i can't recall seeing a bad review in the industry on this amplifier to date, but the irregularity of the measurement should have resulted in some sonic discontinuity. if the measurements change, the question is settled.

CECE
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What kind of distortion does that $10K amp have, you gots to be kiding me. The fan speed is selected by a manual switch, my amps have thermal clixons, it automatically goes to the one of the 3 speeds needed, a manual switch....come on.

jkalman
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Once again JA brings out the reality of a basically poor amplifier with a price tag of $10K!! A damping factor of 12 !!! That must be a loose wooly ill defined 1940' sounding turd. Come on, and of course teh subjective reviewer gives it his blessing how wonderful it sounds. How on earth can such a design be nuetral in reproduction? Freq resspone shows a very limited range this is 2007 lotsa amps are down to DC -500kHz..I know mine are. With slew rates of 800V/uS to make things sound ALIVE. The $10 K unit sounds like one over privced under performer. Subjective listening, must mean teh listener is not interested in natural nuetrral electronics, but a highly colred underwhelming BLOATED mush box. You gotta be kidding Damping factor of 12 !!! In 1950 they did better than that didn't they? And of course it's magical sounding to the subjective one, can't be to lifelike reproduction. Essssh. and it got raves, as usual. Once again JA brings out reality, it's a technical mess. I'm sure it works forever, well made. $10K !!! A 110W...it's also grosly under powered. High end is about hi fi reproduction, bringing back the original performance, not through this kind of stuff? Recently in this months TAS, one writer says, a basic aduio truism, there is no such thing as too much POWER.....Never too much, but so many times way too little. And this 110W pc amp needs a 20A ckt!!! Come on, what kind of poor inefficent design is it? 20A requirments for a home amp..with such table radio output, someone goofed on that design.


Quote:
audio research's response raised my curiosity. if i understand it correctly, they infer a bad tube. if this is correct, let audio research replace the tubes and let john retest the unit. i can't recall seeing a bad review in the industry on this amplifier to date, but the irregularity of the measurement should have resulted in some sonic discontinuity. if the measurements change, the question is settled.

I hate to say it, but even if it is only a bad tube, what kind of quality control do they have at ARC that this got out the door, to a review no less, in that condition? I had been considering ARC amps as a viable option if I decided to switch to tubes, now I'm strongly reconsidering, as I don't have the necessary measuring equipment to ensure I don't get stuck with an underperforming amp....

Elk
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I hate to say it, but even if it is only a bad tube, what kind of quality control do they have at ARC that this got out the door, to a review no less, in that condition?


Indeed.

There are too many products were the review and/or measurements are poor and the manufacturer claims that it is a single bad part or inept adjustment prior to the unit being sent out.

While a traveling review sample could go bad because of the constant moving and jostling around, a unit that gets shipped directly from the manufacturer to the reviewer should be perfect. The customer should also get a unit that is perfect.

A positive note however is that most manufacturers have wonderful customer service to address the occasional problem.

Jan Vigne
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Why are we discussing something that has sat unheeded for almost a month? Is this being discussed just so we know JK had been considering spending the money for Audio Research gear?

If this were a new start up company, the caution would be understandable. From a company such as Audio Research, quality control is not a problem. Tubes go bad. Manufacturers have parts made by subcontractors. Parts go bad. As long as the problem was taken care of in a satifactory manner, this is the reason all companies have service departments. Compost happens!

What is Jeff's problem? That the amp had a defective part? Or, that the amp had a damping factor of 12 when under test? That was dup's original intent of the thread. What exactly is JK now wanting us to discuss?

Monty
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Stuff happens. ARC is one of the good guys. I agree.

jkalman
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A positive note however is that most manufacturers have wonderful customer service to address the occasional problem.

This is very true, as well as your other points. The part that worries me is figuring out if your unit is defective or not. It isn't like anyone can bring their unit down to the Stereophile offices and test it just to make sure. As we have all seen in this review and others, a reviewer can't always tell the difference. If the review sample sounded that good to the reviewer in the shape that it was in, imagine how much better it would have sounded if it wasn't malfunctioning in some way. If he couldn't tell the difference with the unit malfunctioning, yet could have had a better experience with it not malfunctioning, then where does that leave the consumer who has no means of objectively measuring the equipment at home? You can't fix something if you don't know it is broken.

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I hate to say it, but even if it is only a bad tube, what kind of quality control do they have at ARC that this got out the door, to a review no less, in that condition? I had been considering ARC amps as a viable option if I decided to switch to tubes, now I'm strongly reconsidering, as I don't have the necessary measuring equipment to ensure I don't get stuck with an underperforming amp....


Quote:
If the review sample sounded that good to the reviewer in the shape that it was in, imagine how much better it would have sounded if it wasn't malfunctioning in some way. If he couldn't tell the difference with the unit malfunctioning, yet could have had a better experience with it not malfunctioning, then where does that leave the consumer who has no means of objectively measuring the equipment at home? You can't fix something if you don't know it is broken.

Can somebody tell me what the hell JK is talking about? Are there pages missing from my copy of the August issue? Did RR or JA indicate you would get "stuck" if you purchased this amplifier?

Here's what I read in the "Measurements" section of the review.

"The voltage gain from all transformer taps was lower than average; in addition, the channels didn't match very well, the left channel consistently offering a higher level than the right. With a 1kHz tone, the 4 Ohm tap offered 21.2dB gain into 8 Ohms, left, and 20.7dB, right; the 8 Ohm tap, 23.9dB and 23.3dB, respectively; the 16 Ohm tap, 26.4dB and 25.7db, respectively."

Unless my math is off, that indicates an imbalance of 0.5 - 0.7dB, presumably when the load (not actual speakers) is mismatched to the transformer tap. That's with a 1kHz sine wave running through the amplifier. Not music. A sinewave. Worst case, 0.7dB! We have no figures to indicate what amount of imbalance existed at other frequencies or whether JA could hear the imbalance rather than just note it on the scope. RR couldn't hear it apparently while he had the unit in for review.

How many of you believe you could have heard that channel imbalance when the amplifier was playing music material? Audio Research's "Manufacturer's Comment" implied their engineers believed the tube may have drifted off value and therefore caused the channel imbalance. When? We don't know how many hours were on the tubes when the amp was reviewed nor whether JA measured the amplifier in Robert Reina's home. Probably not. Before or after the review? JA probably measured the amp after RR's review was finished. So, the amp was shipped from the reviewer's location to JA and at that point the worst case with a 1kHz sinewave is a 0.7dB imbalance. No new tubes were inserted into the circuit to try to correct a possible problem that might have been caused by a faulty tube.

Hmmmmm. And JK is ready to condemn Audio Research gear as unworthy of his attention due to this "problem", or, as Jeff puts it, "in the shape that it was in". GAWD!!! "In the shape that it was in"?!!! Was this possibly an amplifier that had made the rounds of several shows and dealer demos? Was this current production? Had AR hand picked the amplifier and tested it just before it was sent to RR? How many reasons could there be for a review sample to have a 0.7dB channel imbalance due to a bad tube? But, I guess, Jeff will just have to look elsewhere since his standards are too high to accept such obviously shoddy workmanship. Would he cut AR some slack? Does JK understand that tubes do drift? And that's why there's a guarantee on the tubes from Audio Research?

JK is displaying the type of behavior that salespeople just love to hear. He hasn't spent a dime so far, but he's critical of everything and he knows he's going to get "stuck" with something from your shop. Does anyone think that when JK walks through the shop's doors every salesperson on the floor suddenly has something else to do and somewhere else to be?

Gentlemen and ladies, if you suddenly find yourself alone on the showroom floor, you might keep this in mind.

And it took JK a month to come up with this post.

"When you believe in things that you don't understand,
Then you suffer"

jkalman
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*** You are ignoring this user ***

Sorry, I can't hear you....

Jan Vigne
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I knooooooow!!!

It's difficult refuting poorly reasoned thoughts when the person not making sense doesn't want to listen to anyone else's opinion. But I will persevere.

How'd you know I was here in the first place? I thought I was invisible. What? Is this not really an episode of "Topper"?

Oh, I get it, "Capt'n, the shields are down. The Klingons can see us. She can't take much more, Capt'n!"

I like Topper better.

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