Cornet Transformer Noise

tianguis · « **on:** 30 Jan 2004, 03:13 am »

Hi, all:
As a regular tube roller with the Cornet, I have ample time to get up close and personal. I've been noticing a fairly high-pitched sound when I've been on my knees in the area of the Cornet. Tonight, I turned it off when I was down there and the noise stopped. I can only assume it's transformer mechanical noise. Has anyone else experienced this?

Regards,
Larry Welsh

hagtech · « **Reply #1 on:** 30 Jan 2004, 06:24 am »

Interesting. Not something I have noticed yet. Is there a TV nearby? I realize that makes no logical sense, as you wouldn't be listening to both at the same time, but the horizontal scan frequency of 15.7kHz can be annoying at times.

Does it matter which tubes are being used? All I can think of is something on the power line.

jh

tianguis · « **Reply #2 on:** 30 Jan 2004, 03:45 pm »

Hi, Jim:
No TV, digital equipment or dimmers on that circuit. I also run a balanced power supply with Bybees. The noise is there whether it's receiving a signal or not. It's fairly faint, but has been present for some time. I only tracked it down last night. I'll run it off another circuit later today.
I thought about the tube thing, as I've heard that type of mechanical tube noise, but it seems to do it no matter which signal tubes I use. I guess I'll try a different rectifier, too.

Regards,
Larry Welsh

tianguis · « **Reply #3 on:** 31 Jan 2004, 10:35 pm »

Jim:
Pulled the Cornet out of the rack, plugged it in to another circuit. It's transformer noise. Swapped out the rectifier and all the other tubes while I was at it. Nothing changed the noise.

Regards,
Larry Welsh

hagtech · « **Reply #4 on:** 1 Feb 2004, 12:59 am »

I'm baffled. My next thought is a corona from a high voltage arc. I know directionality is difficult to determine, but can you tell if sound comes from transformer or board?

jh

tianguis · « **Reply #5 on:** 1 Feb 2004, 02:19 am »

Jim:
I've experienced corona noise, and I don't like it one little bit! Very irritating. However, since I had the Cornet out and available I made a change in input loading resistors to better mate with my Benz Silver (whose cart loading specs are erroneous!). There's nothing visable on the board and the first transformer didn't make any noise at all. I haven't changed a thing since I installed this one. When I did, it also was dead quiet. The noise has crept in only lately.

Regards,
LW