Both channels?
120hz hum coming from all-tube system - but only at high volumes
I generally listen to my system at 8-9olcock on the volume dial. A friend and I were pushing the dial up to 11-12 oclock and a fairly loud 120hz hum would start to appear after a while.
Bringing the dial back down would eliminate it. You could then pushing it back up and it'd be fine for a bit and then then hum would reappear.
Do I have bad tubes somewhere? Ground loop that only rears its head occasionally at high volumes?
(System is Manley Steelhead pre, Manley Mahi's mono amps, Forman Elite-15 PFi power conditioner, schiit yggdrasil DAC, Klipsch Forte IV speakers)
Bringing the dial back down would eliminate it. You could then pushing it back up and it'd be fine for a bit and then then hum would reappear.
Do I have bad tubes somewhere? Ground loop that only rears its head occasionally at high volumes?
(System is Manley Steelhead pre, Manley Mahi's mono amps, Forman Elite-15 PFi power conditioner, schiit yggdrasil DAC, Klipsch Forte IV speakers)
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If it was there all the time and only became audible at high volume then I would say it is just the way it is, perfectly normal run of the mill noise, and you can track it down if you think it is worth it. But "occasionally" and "fine for a bit" then reappears indicates to me this is heat or power related. Could be a tube, could be something else, but more than likely not right. Since you run mono then if it is both then probably not the amps, but more likely the preamp. |
I suggest you get thee a simple tube tester to help diagnosing this problem and have for the rest of your life https://www.ebay.com/sch/i.html?_from=R40&_nkw=tube+tester&_sacat=0&LH_TitleDesc=0&_... make sure you get the manual or can download it. I am going to part with my 157, works just fine, I recently bought it’s bigger brother 257. tested my preamp’s 17 tubes on both to confirm, they agree with each other on their meters. seller says this one has problems, just to show a 157 https://www.ebay.com/itm/274957651485?hash=item4004c0ce1d%3Ag%3APQUAAOSwHeZhS3Ng&LH_BIN=1 this 257 to see it, this one also has comments https://www.ebay.com/itm/393411222024?hash=item5b9922da08%3Ag%3Aki4AAOSwcXhgzNw-&LH_BIN=1 |