Noise in left channel of my BC

[mike_b]

Ordered Crack. Received Crack. Built Crack. Tested Crack. Connected Crack. High on Crack.

Love this amp. However, I am experiencing what sounds like a creaking sound in the left channel and with the volume turned down on all sources I still hear it. I resoldered all the joints, rechecked the wiring, voltage and resistance, none of the caps are blown, cleaned the pins on the tubes and checked for any possible shorts. My on/off switch stuck to the on position (It got hot during my initial solder, my bad)

If I adjust the 12AU7 in its socket the noise tends to lessen but it comes back and I assume that it might be the 6080. It is not a hum or a buzz because the right channel is dead quiet. It sounds like a creaky, rusty gear turning and it is very consistent. And it starts up as soon as the tubes warm up after about five minutes. I cannot hear it during the music but I know its there. I have over thirteen hours of burn time on the amp since I finished it.

I read Doc's diatribe on noise and the only thing it might be is a noisy tube. I am using Senn Hd 650's and they are perfect for the BC. I checked them out on two other sources so they are not the cause of the noise I am hearing.

Any feedback is appreciated.

Thanks
Mike B

[davew]

The info you read from Doc is likely spot on. I have a 1955 RCA 6AS7G which also "creaks". This tube has been noted to be noisy. I plan to test and swap in two others I have to hopefully find a quiet one. My stock 6080 is fine.

[Natural Sound]

Agreed, sounds like a noisy tube. I've come across several different tubes that make that kind of noise. If the tube is new or NOS you might just want to run it for a while. PJ talks about tubes taking a while for the cathode to form. 13 hours isn

[mike_b]

Thanks for the feedback. I have decided to order some more tubes. The tubes for my Millett hybrid don't fit so I am looking for a good vendor. I live in Arlington, Texas so a local dealer would be great. Online will work. This forum is great. Glad I did this. It's been forever since I built my Dynacos. This was a fun kit. It sounds sooooo good.

Mike B.

[davew]

If you need to go online I've dealt with Tube Depot at tubedepot.com. You'll find a selection of both new production and NOS. You could also try the eBay route if you have an account there. I've bought and sold in that arena (davew951). I'm currently selling a bunch of Sylvania JAN 6189 matched pairs. Good sub for 12AU7. I may also be listing my spare(2) 1955 RCA 6AS7G tubes later this week. (I hope I'm not breaking any forum rules with these comments.)

[Natural Sound]

If you need to go online I've dealt with Tube Depot at tubedepot.com. You'll find a selection of both new production and NOS. You could also try the eBay route if you have an account there. I've bought and sold in that arena (davew951). I'm currently selling a bunch of Sylvania JAN 6189 matched pairs. Good sub for 12AU7. I may also be listing my spare(2) 1955 RCA 6AS7G tubes later this week. (I hope I'm not breaking any forum rules with these comments.)

Usually Doc B would prefer it if you check with him first before advertising on the forum. If the sale of your items goes towards funding a new Bottlehead kit its easier to get approval. That said, Doc is pretty cool. If he has issues with your advertisement he will let you know.

[Doc B.]

It's cool in this case and thanks for asking. Best way to do it in the future is to send the other poster a PM.