Possibly a ground loop. The only safe way to fix it that I know is to get an isolation device like an isolation transformer.
Tracking down a hum.
Today when I powered up my system, I noticed a hum from my tube pre amplifier, a Rogue Audio Model 99 (line stage only). It is worse when first powering up. It is absent through my headphones, (using an external headphone amp and the record button on the pre-amplifier) Listening to speakers the noise is present but diminishes and eventually goes away as the system warms up.
I'm using the Rogue to send a signal to a Musical Fidelity X-P200.
I don't think the issue is the tubes as I'm using Tung-Sol 6sn7 tubes with less than 300 hours on them.
I bought this Rogue used and had to take it back to get it fixed as one channel kept cutting out because of a bad solder in the out put jack. Maybe something else failed?
TIA
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Hello dierksb. It sounds like a failing electrolytic capacitor in the power supply to me. The hum starts out bad and eventually diminishes. An electrolytic capacitor is a can of goo that forms bubbles on the inside of the can which forms the insulation. Its taking a while for the bubbles to form and its not so bad that the capacitor begins to act like a resistor and allows dc current to flow through it. At that point they often "blow up." I recently bought an Arcam receiver which erupted in flames when I turned it on. It blew a 15 amp fuse and smoked up the room for a while. a competant technician should be able to locate the bad cap in 10 minutes or so. Get it checked before it goes. |
- 41 posts total