BC30 & Whistle Noise

[MikeRom]

Trying to tame the hisssss of my BC30, I first replaced the 6L6's with a matched pair from Electro-Harmonix. Didn't cut the hiss. I had some Goove tube 12ax7's lying around so I swapped out a few. Shortly after doing that it started producing what I can only describe as a high pitched whistling, and very loudly. More pronounced in the over drive channel but still somewhat audible in the clean channel too. Pulled the tubes to put the originals back in, maybe I had a bad tube. Anyway, when I installed the Groove tube in T3 I bent a pin. Ah-HA I thought. Played away and all was whistle free for a while but I'll be darned if it didn't come back again. Turning the volume on the OD channel up and down I could hear that it was the fan causing the noise, some how feeding back into the signal. I planned to disconnect the fan, maybe it's bad, when the other guitar player in my band who is not mechanically or electrically inclined - at all - suggested that I try a different speaker out. First I scoffed, if the noise is in the signal won't matter which output I use. Then I thought, what the hell, can't get any worse and whaddayaknow and I'll be dipped if that didn't solve the whistling problem. And it never came back. Was using the 8 ohm speaker out that's right next to the 4 ohm speaker, changed to to the 8 ohm out next to the 16 ohm out. Weird huh?

 

Still need to tame the hiss tho ...