ARC amps do not explode. Occasionally, if an output tube arcs, a resistor might blow which is what it is supposed to do.
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I owned an ARC D125 that I bought used in the 90's that had an output tube internally short and the amp burst into flames rising up 6 inches above the amp which was destroyed. The dealer said he had 6 other customers with the same amp that used Chinese 6550's that also went down in flames. The driver and bias PC board was destroyed.
I admit to having an ARC bias (pun-LOL), but here is my experience. I've owned 2 ARC tube amps: the VS-110 and currently, the VS-115. Yes, it's true, on rare occassion (maybe twice), a power output tube arc'ed and took out a bias resister.
I'm fortunate to have an authorized ARC tech. service rep. who's shop is near my house and who also makes house calls. When my VS-115 blew a power tube and took out a bias resister, the tech came to my house and replaced the resister in 45 minutes. The repair was fully covered by the ARC warranty.
Look, tube amps on occassion blow power tubes and in some cases take out bias resisters. It goes with the territory. But I have never experienced an exploding amp problem. I may have read of one case on the Forum where an arc'ing tube did a lot of damage to an ARC amp, but not an explosion.
Post script -- I replaced all the power tubes in my VS-115 with KT-120s. Aside from my sense that these tubes greatly improved the sound quality of my VS-115 as compared to the old 6550Cs, I understand that the KT-120s have a more robust build quality. So far, evrything is humming (pun - LOL). Again, FWIW.
Perhaps Gary (Hifigeek) can weigh in on his KT-120 experience. Gary is an ARC authorized service tech.
Well KT120's arc just like 6550's do. Possibly a bit less often. With regard to the Chinese 6550's of decades ago. Frankly they were awful tubes. But that was all that was available. They looked like the Tung Sol coke bottle 6550 but that's where the similarity ended. Their failure mode allowed the heater to work but not much else. The light was on but no one was home so to speak. I'm guessing in the D-125 more than one tube arced at the same time. The Chinese tubes liked to do that back then. The only Chinese tubes I will use even today are the EL-34 Treasures. That's it. Once bitten twice shy. Remember, at the time the Chinese were making the 6550, the Russians were still trying to gear up to make one. ARC helped the Russians make the 6550. I just wish they hadn't initially used the GE 6550 as their model. I always thought the Philips Sylvania 6550 was a much better tube. Initially the Russians were trying to change one of their stock beam pentodes into a 6550 but that failed miserably. The Russians never stopped making tubes. Remember, the Winged C 6550 was probably the 12 version of the Russian 6550. Trust me, I saw every single version of that tube over the years. Some good some not so good, and some without any getter flash at all. The KT-120 represents what is considered to be state of the art in Russia. The KT-120 looks to me to be a modified version of one of their radar tubes. It's a winner.
I have used tube amps since 1974---that's 38 years---and I have never experienced the type of reliability problems that are routinely reported with ARC amps. My amps have ranged from old vintage units to modern designs, mostly push-pull but some single-ended DHT. None of these amps have had the fireworks, sparks, smoke, etc. that ARC amps seem to produce sooner or later.
What this means to me is that I decided many years ago never to buy an ARC amp. No matter how good it may sound, I have no interest in even an occasional fireworks display. Instead, I have stayed with amps that are designed more conservatively. When tubes eventually fail, the amps stop working and there may even be a blown fuse, but never fireworks.
What really bothers me is that someone could read these forums and conclude that all tube amps have these problems and use that as an excuse to use only solid state. That would be a real tragedy. Choose your tube amp carefully and you should have many years of trouble-free good sound.
Salectric, again . . . I may be biased in favor of ARC:<), but I've been around a while too - will be 60 in about 2 months :<( ....
My general recollection is that by way of reputation, ARC gear was generally at the top of the food chain. Yes, they made a few dogs over the years, but sh*t happens.
All my gear is ARC and I must tell you that except for the rare tube arc'ing experiences, the stuff is top notch dependable. IMHO. Perhaps Gary (Hifigeek) may want to share his thoughts too. I suspect he'll probably come out where I do.
It could very well be tube type/family.I`ve had several 6550 tubes fail(friend same problem with some KT 88) early in their life. EL 34 were never a problem for me over many years.My current amp uses the 300b and these are the most reliable and best sounding of any tube I`ve used.\I wonder if the DHT tubes are inherently more rugged and durable.The DHT seem to last a lot longer also.
FWIW, I've had my ARC VS60 since Aug. 2010 (bought new; discontinued by ARC shortly thereafter). Basically the same unit as the VSi60, but it is not an integrated. No problems so far, knock on wood. I plan to replace the 6550's with the KT-120's when they approach the end of their useful life. Keep in mind that the Stereophile mishap happened on the test bench while being driven to levels approaching clipping.
Appreciate all the responses. My main concern was that ARC seemed to have more anecdotal evidence of reliability issues. Like I said, I don't mind the biasing, replacing tubes, general maintenance etc, but I don't want to have to deal with replacing resistors on more than one occasion to get my amp running. I've always enjoyed demoing tube gear, and always chose tube amps for guitars, but don't want to if I'm going to have to get warranty work done repeatedly.
I would not blame ARC but rather the tube manufactures. Quality is up and down. Since you have the choice of 6550's from Russia or China, I choose Russia. Tubes are not at all like transistors. Once a tube is on, it's going downhill. Some blame also goes to the consumer. When ARC says their output tubes are rated for 2000 hrs. they mean it. I can't tell you how many ARC amps I've seen that were abused. When your 2000 hrs are up that doesn't mean to wait till a tube arcs to replace them. It also doesn't mean if one tube fails, just replace that one tube. It also doesn't mean if the fuse blows, up-size the fuse. When you buy a Ferrari, don't put regular unleaded in it. Any tube amp from any manufacturer can arc a tube, it's the nature of the beast. Treat it well, and it will last many lifetimes. Abuse it, and it won't last long.
There may be some tube amp companies that have reliability problems, but I don't think ARC is one of them. I've owned at least half a dozen ARC tube amps/preamps since 1978, including a VS55 and VSi60 currently, and I wouldn't keep buying their products if I had been experiencing problems with them. Yes, tubes have to be replaced, you have to make sure the bias is set correctly, and occasionally you may have to replace a resistor if you own the amp long enough, but this company did not gain its reputation by making unreliable products.