Tube and Tube Socket Cleaning

I have a pair of RT 12AU7's of which one of them is noisy when powered up. I have switched it from side to side in my pre-amp (CJ PV10A) and the noise follows. I sprayed a great deal of compressed air into the tube socket and around the prongs of the problem tube and this has diminished the noise greatly, but not completely. I spoke with the dealer and he advised me to take a fingernail file and gently file the prongs on the problem tube. Any thoughts on this???
He also mentioned that there were tube socket cleaning kits available. Has anyone had any experience with these or can anyone recommend one?


Brad Day
Atlanta, GA

PS My searches on Audiogon for this information did not turn up any matches.
Gently filing the prongs as you propose, I have also found helpful and afterwards a good cleaning with Kontak or just a tiny bit of Craig ProGold certainly helps. For the sockets, I use these tiny brushes which are sold for cleaning the cavities between your teeth with very good effect, followed by a tad of Kontak or Pro Gold as well. Cheers,
what kind of noise is that? microphonic? ac? hissing?
i just realy wonder how the other socket isn't noisy being basically as "dirty".

the cleaning doesn't help everytime as in this funny story:

a blondie is trying to start up her malfunctioned mercedes without any success. another blondie in jaguar drives by stops and trying to help:
--did you wipe your dashboard?
--did you wipe your head and tail lights?
--yes i did!
--did you clean your rims?
--and still you can't start it?
--sorry, can't help you than!

as to cleaning tube prongs and sockets it's considered to be a basic hyegine that you should excersise once in approximately every 300 hours. i use kontak with supplied wire-shaped brushes that can penatrate even sockets for small signal tubes all arround the sockets and prongs. if the oxiding is visible it's probably fine to use the fingernale file while i use de-oxiding spray and still try to remove it the "gentle way".
Thanks, Detlof. Also, did you use a metal nail file or a wooden one with the sand grain on it? And, where might I find Kontak or Pro Gold locally (Atlanta)?

Thanks again.
Rt 12AU7 are a noisy tube.Most of whats around and comming out of the left Coast is pretty noisy period
sounds to me like the tube is bad, not the socket. It follows from side to side when moving that tube? Send it back.

I use two methods. For tube pin cleaning, a common pencil erasor works well. Also, one of those fiberglass cleaning tools available from Radio Shack will take the crud off the tube pins. The tool is also small enough to fit inside the tube pin sockets as well. Just rotate the thing a few times and the flexible bristles will clean the pins and sockets to bright metal without removing any material from either. I chuck the pen shaped tool inside my rechargeable drill for stubborn cleaning jobs. Follow-up with deox-it or similar for a years worth of scratch-free listening.
I use Kontak (or electrician's alcohol on non-plated items) along with a pipe cleaner (for sockets) and a toothbrush for pins. On extremely tarnished pins I use the very smooth purple sandpaper which is cloth backed (can't ever remember the name of it). A "file" is too rough, IMO. Pro Gold and other cleaners have been "said" to leave a residue which later gunk's up due to the heat generated by tubes. The two cleaners that I use do not have this problem. Electrician's alcohol is "said" not to be good for plating (gold and otherwise) as it is too strong and in this case the Kontak seems to be fine. The main thing is to be gentle with the metal surfaces. If the tube is still noisy following a good sprucing up, then it is a noisy tube (this happens). I live on the "left" coast and have some mighty fine (and silent) 12au7's (by the way:-).
Dekay that's called Crocus cloth: found at better hardware stores. I wouldn't be without it myself; great for burnishing.
The type of noise was static-like.

I'll try the Kontak and see how it goes.

Thanks, y'all!!!!

I also use Kontak on a regular basis to clean all connections. Kontak can be ordered from Perhaps the tubes need replaced? When you switched them, did the static change sides?
bday: DON'T use nail-files, Crocus or extremely light sandpaper will do. You can use thin pipe cleaner for the sockets! "Detergents"-wise Kontak or Cramolin have worked for me...
Lak wrote: Perhaps the tubes need replaced? When you switched them, did the static change sides?

Yes, it did change sides. However, I thought that maybe this one tube was exposing a problem my pre-amp was experiencing on both sides. The pre-amp (CJ PV10A)is about 10 years old so it (really, really) needs to be cleaned up anyway. The tubes I installed are new.

Thanks, all!!!!

most-likely caps become to be statically noisy and need to be replaced especially ones in ground isolation circuitry.
measuring capacitors for the face value +-tolerance isn't an easy task and require havin an osciloscope to measure the discharge time so without any checking and suffering setting up an oscilloscope for the right scale just change them all by face value and with better quality.
checking low-wattage bias resistors is much easier task for the rated value.
fuses within such period of time even if functional can create an extra noise.
whenever you change the caps you should run your preamp(approx 1 hr) on no-signal operation meaning that you will have an input connected with muted or unpowered source.

Brad, as Greg suggests, sandpaper will do very well, because you can fit it round the prong. I don't see any harm in using a nailfile though. I've both used the metal and the wooden ones- gentil and carefully though, just enough to take away the oxidation. Don't know where you can get Kontak in Atlanta. You could try Audio Advisor via mailorder. Craig Pro Gold probably also from them or directly from the Craig webside. (Am not sure now, if it is CAIG or CRAIG ) Cheers,