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Old 19th April 2004, 05:49 PM   #1
August is offline August  Netherlands
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Default Goertz: amp killer? or where to fix my Audio Research VSi55?

I bought an Audio Research VSi55 integrated secondhand from Hongkong. It arrived today so I set it up carefully and had a quick listen. I adjusted the tube bias for 65mA. After that I turned up the volume to listen more seriously, as the amp was getting nice and warm. All of a sudden the amp made a noise and there was some fireworks+smoke coming out of it.

I use Alphacore Goertz cables. I really like their sound, but I have had some problems with them in the past with my SS amp. They can cause instability in some amp/loudspeaker combinations, which tends to overheat the amp. This is not common, but Alphacore does offer sets of R/C match links to prevent this from happening. This is why I always use them since I had problems with my Densen amp. Also, this time, I had them installed on the top terminals of my JM Reynaud Trenté speakers. The Alphacore Goertz AG1's where on the bottom terminals and I had some bridges between them.

I am now thinking I should have had these installed on the terminals that I had the cable on as I am not sure if the top terminals are the tweeter connections as these speakers have a woofer with two voice coils, so electrically a 3-way. Anyways I love the sound of Goertz, but if they are the reason for this defect I will have to let them go and search for other cables.

The really bad news is that I called the Dutch importer and he refuses to help me because I did not buy this amp at a Dutch dealer. Frankly I think this is ridiculous. I am being punished for buying a completely legitimate secondhand device that was originally sold in Hongkong 2 months ago. I know that the official warranty is only for the first owner, but he could at least help me out, I would even pay for the repair.

Now I have a broken amp and the official importer and his dealers won't help me. First of all I would like to know how I could reach Audio Research, to see if they could help me. I don't think it is a normal thing for a $3000 amp to break down like this using quality cable.

If they can not help me, I will have to find someone else who specialises in tube amp repair. I do not know a lot about tube amps, but I opened the cover and saw two big resistors that have burnt, but I do not know if there is any other (invisible) damage. I could really use some advice. This amp is essentially the same as a VS55 apart from the passive preamp stufff.

High res pictures of the amp:
http://mini4stroke.speedlinq.nl/VSi55a.jpg

http://mini4stroke.speedlinq.nl/VSi55b.jpg
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Old 19th April 2004, 06:03 PM   #2
SY is offline SY  United States
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It's doubtful that you'll get ARC to help defray repair costs. And the reaction of the Dutch importer is entirely understandable- you went around him, denied him his markup, and now you want him to help you. Maybe you should ask Goertz to pay for the repairs?

In any case, from the photos, it looks like you've lost some regulator parts. I'd replace the burned resistors and the power transistor they're connected to. Then stop reading hifi magazines and replace your cable with something reasonable that doesn't have to put bandages on to make up for an unreasonable capacitance.
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Old 19th April 2004, 06:36 PM   #3
August is offline August  Netherlands
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First of all, I would pay for any repairs because I understand that I do not have any legal right to the normal warranty. But he simply refuses to do anything with an amp that he didn't import himself. I wonder how this attitude would serve him when someone migrates from another country and needs service for his cherished amps? I did not do anything illegal, just bought a secondhand piece of equipment from Audiogon. It is not stolen nor parallel import. In all fairness, this particular importer could be a little more lenient towards me by at least repairing this amp at my expense. In stead he treated me quite harshly which I don't think I deserve.

Second, I already wrote that I am considering buying a different brand of cable. For your information, I stopped reading hifi magazines some years ago and even if I still did read them, that is not the issue here. These cables do a lot of things right and if you've read Allen Wright's cable cookbook you would probably know there is scientific theory behind this sort of geometry that I doubt many other far more expensive cables have. I don't want to make this into a discussion about these cables. You probably either love them or hate them. I like them, but if they are the source of my current problems they must go. I am going to call AR to see if they can at least confirm that these cables are to blame. Maybe they could also assist in getting the amp fixed, because I am quite appalled at the treatment I got from this importer.
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Old 19th April 2004, 06:45 PM   #4
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Default Re: Goertz: amp killer? or where to fix my Audio Research VSi55?

Quote:
Originally posted by August

High res pictures of the amp:
http://mini4stroke.speedlinq.nl/VSi55a.jpg

http://mini4stroke.speedlinq.nl/VSi55b.jpg
Ha Ha Ha. 1.7Mb photos. Give us a break.
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Old 19th April 2004, 06:55 PM   #5
EC8010 is offline EC8010  United Kingdom
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Hey guys! Give the man a break! His new toy's just blown up.

August; I think you're going to have to look for a decent engineer to fix the problem. Trouble is, I notice that once again, AR have used a "selected" device (probably a FET). Unless you can obtain a circuit diagram, fixing it is going to be expensive because whoever fixes it will need to trace out the diagram, and work out whether that "selected" device needs replacing, and if so, with what.

I hate designs that require "selected" devices to work.
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Old 19th April 2004, 07:08 PM   #6
August is offline August  Netherlands
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EC8010; thanks for your sympathy and the helpfull comment, seeing this almost new amp going up in smoke was not a pleasant experience.

I will first call AR to ask them for some help. If this fails, I will try and get some help elsewhere (i.e. a tube expert in the Netherlands or Belgium, of which I am sure there are some on this forum)
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Old 19th April 2004, 07:11 PM   #7
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Default Re: Re: Goertz: amp killer? or where to fix my Audio Research VSi55?

Quote:
Originally posted by Bill Fitzpatrick


Ha Ha Ha. 1.7Mb photos. Give us a break.
14 seconds to load a picture, not unreasonable I think,
the pictures are good

cheers
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Old 19th April 2004, 07:35 PM   #8
August is offline August  Netherlands
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Well two thumbs up to Audio Research, they were very helpfull.
First of all they have had Goertz samples for testing and have never had any problems whatsoever with it. Their tube amps are very stable and should be indifferent to any cable or speakers, regardless of high capacitance, low inductance or otherwise.

He suggested that the amp might have had some shipping damage which was not apparent from the outside, but they will service any AR gear no matter where it was sold so I'm going to send it to them. He also offered to test my speaker cable for anomalies to see if that might be the problem, although he didn't think so.

Now that's what I call service!
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Old 19th April 2004, 07:46 PM   #9
SY is offline SY  United States
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Excellent, congratulations. And kudos to ARC for being willing to go above and beyond.
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Old 20th April 2004, 03:41 AM   #10
DougL is offline DougL  United States
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My brother repaired an ARC 6550 amp for a friend recently.
The tubes failed and let the smoke out of the cathode resistors.
He was saying that the cathode resistors were sized to protect the transformers in case of tube malfunction.
ARC sold him 10 for $10, he replaced the 2 bad ones and the 6550's and went on his way.

Sounds like it may be the 6550 outputs were damaged in shipping and failed short.
If you don't have a schmatic, you can buy one from ARC.
Replace the resistors and see what happens before you ship it halfway around the world.

Good Luck.

Doug
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