Hi Tony,
That's interesting. I messed about a lot with that age of Rowe Ami. In fact that's the only Amp/Preamp that I know anything about. I've never experienced your problem but had some similar interference down to a lighting choke some years ago. I tend to pull the mute plug from the amp and do a bit of diagnostics without the mech in play mode. Just makes life a bit easier to diagnose it. I guess if you did that with the mech at rest, your static would have disappeared. I'll know next time if I get static to pull the turntable power plug to the side of the mech. Owning a JBM for almost 40 years I think I've experienced every flipping problem that machine can throw at me - and they do ! Usually the cue for a problem to arise is half an hour before guests arrive.
Earlier this year I had really bad static and it turned out to be the base of one of the inverter valves. It drove me nuts, but did force me to replace all remaining old resistors in that area of the amp, so at least I came out of it with more improvement in sound.
Nigel, uk
On 5 Sept 2025 at 14:08, Tony Miklos via Jukebox-list jukebox-list@lists.netlojix.com wrote:
Just wanted to share this.
I have an AMI JAL in the shop. One of the many problems was an intermittent static like noise in the speakers. I thought it had the sound of a 60 cycle arc, if you can imagine that. It didn't do it on the bench, but it was intermittent. It was very loud and would go up and down with the volume control. I pulled the inputs and it still did it. Started pulling tubes in the pre amp, then in the power amp. It didn't completely go away until I pulled all 4 output tubes. Somewhere along the line I had even unplugged the pre amp from the power amp and only had the output tubes in it. (they tested good) It still had the noise but very, very quiet. I had to have my ear close to the speaker to hear it.
To make a long story a little shorter, it was a bad turntable motor cam switch arcing and causing interference. When I pulled it out, it had about 80 ohms resistance. (Even with the bad switch in, it still played records at normal speed.)
It now makes me wonder if I had had an arc fault interrupter circuit breaker in my electric panel, if it would have tripped.
-- Tony Miklos Tony's Jukebox Repair
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