💩 happens and it’s frustrating when it does. But I’ve never heard “poorly designed” in the same sentence with Audio Research. Fixing the issue is worth it because ARC stuff sounds great.
Audio Research Reference 150 - buzzing input transformer
Hello everyone,
I have bought a second hand ARC REF 150 power amplifier (non SE, KT120 tubes) and there was a buzzing noise coming out of the input transformer after few hours. I have detected the noise appears as the amp fully warms up - after about an hour. It goes pretty loud within another 30-45 minutes.
I have taken the amplifier to a friend, a reputable tube amp engineer. He told me the input transformer must be replaced and also that in his opinion it was poorly designed.
I live in Europe so I didn't have the chance of sending the amp to the factory, nevertheless, a new transformer is on its way and I'll get it fixed by an authorized dealer and service.
I was also told that the problem may happen again and that I should get rid of the amp.
My question is whether any of you had similiar problems and what the cause can be. I really love the sound of this amp and of course I'd like to keep it. I'd also like to do as much as possible to keep the amplifier safe.
I have found a very similiar discussion here on Audiogon, I have messaged the OP and he replied he had his transformer replaced afterall -
Is there anything that can cause the transformer to overheat and melt inside? The noise was caused by a vibration of the plates inside the transformer.
My speakers are Tannoys D700, they go down to 3 ohms and I can imagine they are current hungry even tho their sensitivity is 92dB. They worked well with a Classe CA-200 but the ARC sounds a lot better of course. I'm planning of upgrading the speakers in about a year but for now, I'm still very happy with these, it's always a pleasant surprise when I upgrade any piece of gear.
I have asked the ARC company whether the speakers won't be a problem for this kind of amp. They ensured me I'd be fine and that they test their gear with much more difficult loads.
The amp never got too hot when I placed my hand on the top of the chassis, the tubes were measured and they're fine, about 1100 hours on them. The amp wasn't in use for a few years before I bought it.
Thank you for any suggestions.
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If it's the presence of DC, it must have happened quickly with permanent damage on the transformer. After I took it to a friend's place, it behaved the same even after plugging it into a power plant. And it would be interesting if this was the only piece of gear being damaged. My LS16 preamp works great, there's also slight buzz but I think it's normal. It's only audible when I place my ear right above the mesh cover. @audphile1 yes, it does sound pretty amazing 🙂 Is it expensive to replace those capacitors? I'll definitely have them checked if possible.
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- 23 posts total