Tube Noise

audioluvr wrote: »

Hey I have a tube question for you all. My tubes are starting to get noisy. I only hear it between songs. The right channel just has a dull steady hiss I can hear if I stick my ear up to the speaker and the left one sounds almost like it's picking up interference from short wave or something. Should I replace them? Or is there something else going on internally/externally that the tubes are picking up?

What component?
...and what tube type(s)?
PS Why do you assume it's the tube(s) and not, e.g., a resistor?
Admittedly, I live in a vintage world where the biggest culprits for hiss type noise (other than in a high-gain stage such as phono or tape head preamp) are carbon comp resistors and silver mica capacitors.

I use a stainless steel brush from Harbor Freight. It works REAL well on tubes that do not have a guide pin {6sn7}. I just hold the tube and move the brush back and forth and circular in nature. I then spread some red deoxit on a toothbrush and do the same on the pins set aside to let dry/evaporate some so none is running off the pins into the electronics below. Honestly I do not use so much that it would, I rather be safe.
Those that do have guide pins I use a 3M green scrub cut to a size that works easily to get between the pins and guide pin. I've even used a piece of 800-1500 or higher wet/dry sandpaper then blow off. Personally I've not found anything that cleans the socket well for 9 pin tubes. All the super small brushes I've found were too large, definitely don't want to make those bigger, or break them. I just work a firm toothbrush on the sockets best I can get it in.

GlennDog wrote: »

FOLLOWING

heiney9 wrote: »

Pull them and clean the pins and if possible clean the sockets. You'd be surprised how a good cleaning can eliminate noise.
H9

Hey brother,
It would be extremely helpful if you could point to a link or briefly, describe the quickest easiest way to clean the pins and/or sockets.

I’ve got a handful of tubes that I’ve condemned, and I’ve saved them for this very reason.

I’d love to bring these bad boys back to life… TIA

I don't have a specific link. I can tell you what I do. Get some of these low/no lint cleaning swabs off Amazon or your favorite electronics supplier.



I usually use De-Oxit. Moisten the swab and hold your tube with gloves to keep body oils off the glass. Vigorously clean PINS, 360*. Discard swabs as they start to turn gray from oxidation. If the swabs turn gray, I usually go over the pins again until no more gray.

For heavy oxidation I have a small wire brush kit with various stiffness bristles. "Brush" the pins with enough vigor to remove stubborn oxidation, but you don't want to put grooves or scrape off any coating on the PINS. Then do step one.

I clean the tube sockets with small pipe cleaners. This is a more delicate process because you don't want to expand the sockets so they no longer hold the tubes lightly.

12V signal tube sockets are tedious because they are tiny and you don't want to expand the tines that grip the PINS. Part of the problem is if you put oxidized tubes in the socket some of the oxide stays in/on the socket. I always clean tube PINS before inserting. That process will keep your tube sockets clean (and lubed) for the most part.

Get in the habit of cleaning PINS before inserting. That cleaning should last a long time if the tubes are stored indoors in normal humidity.

Hope this helps.

H9

Threads like this are why I love this forum! So many are eager to help others. Such good eggs!

I've never tried it, but I bet this would clean the sockets:

https://www.grainger.com/product/2CYY5

Regarding tube socket terminal cleaning. I have some, somewhere...but you can get tiny brass or stainless brushes. Brass will be less aggressive. The ones in picture start out at .6mm/.023."

I have used spiral torch tip cleaners on really nasty old receiver tube sockets. They are the break glass in case stainless didn't work. Start out small with those as they are like a file and will remove material. A Dremel cut off wheel or side cutters can lop off the pilot end. You can see some of my tip cleaners are trimmed to business end.

Nasty tube pins can also be cleaned with Dremel using brass brush, but you have to be careful.

When using DeOxit D5 I like to follow it up with a 99% isopropyl flush.

Tube pin straighteners are very handy to have too. Bent pins can loosen the terminals in socket.

mhardy brought up a good point. If carbon resistors are bad I and others like to replace them with metal film resistors. They are more stable as carbon values can change as they heat up.






The Scott 340 and 399 (early '60's) I refurbed had some nasty tube socket terminals. 18 tubes in the 399.

I was set to replace my tubed pre but decided to have the sockets cleaned, glad I did!

Would a pipe cleaner get into the sockets?

Never have had the pleasure of anything toooobed.

skipshot12 wrote: »

Would a pipe cleaner get into the sockets?

Some pipe cleaners have a metal core. I was cleaning the sockets on a VTL preamp and even after being unplugged, I received a thump in the arm when cleaning the sockets.....woke me up real quick and I don't recall what I was using but it was a good hit.

Please, please be careful and be absolutely sure the power supply caps are discharged.