|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
50.151.166.185
Sorry this is kind of long...Recently there have been a number of noise related issues posted here, and I've gotten an unusually large number of emails about them as well.
Inevitably, the very first thing I ask is "are the sockets and tube pins really clean, and do the sockets grip the tubes tightly?". In many cases I'm met by disbelief and I get the distinct impression that people think I'm just trying to hassle them or trying to avoid standing behind what I sell (if I sold them the tubes). But not always...
Here is the original email I got from a gentleman who had a very unusual issue with his new tubes:
Hi Jim,
Purchased matched quad KT88 Sept. 9, 2015. Professional install and bias by XXX XXXXXXX of XXXXXXX Labs. Ringing of one pair developed. Subbed old KT 88s - no ringing. Please advise for return/ replacement.Here was my reply:
Hi John,
Sorry to hear of trouble. Can you tell me what you mean by ringing? Let me know also what amp you have them in. We'll take it from there, thanks.John got back to me with a description of what he is hearing:
Hi Jim,
Intermittant siren sound of the same pitch. The sound lasts five to ten seconds then lapses, only to return. Occurs when preamp volume set at zero, as well as when partly masked by music. Used in Shindo Corton Charlemegne 80 monos.That is quite an unusual set of symptoms, and John originally felt it had to be the tubes based on what he experienced as described above. But I wrote him back and asked him to do one thing for me:
Two last questions John - and only because this is highly unusual. I have never had a power tube do this except if they aren't making good socket contact.
1. Are the tube sockets clean, have they been cleaned recently? And are they gripping the tubes tightly?
2. If you swap the suspect tubes into the other channel does the noise follow them?
Actually let me also verify - the noise is coming from the speakers, yes? Not the tubes themselves?
If you can let me know on this it'll be a big help.John replies
Jim,
I will follow your advice on cleaning and rotating the tubes, then I will get back to you. The sound is coming from the speakers.A couple days later I got this email from him:
Hello Jim,
Took your advice and cleaned the tube sockets... all now seems well.
Thanks for your quick replies and support. Happy holidays to you and yours.THANK YOU John!! Your cooperation saved us both a lot of hassle.
Keep a couple things in mind:
1. Tube sockets - even really good ones - are not sophisticated, high reliability connectors. You won't see tube sockets in critical applications because they simply are not reliable enough.
2. Replacing a "bad tube" and having the problem disappear is not a conclusive diagnostic procedure in MANY cases. The insertion and removal of a tube may scrape away an area where the pin-to-socket contact can be temporarily reestablished, but is not conclusive - just ask John! Sometimes the two tubes have slightly different pin diameters and one will contact while the other does not - this is especially true if you are replacing a tube with "fatter" pins than the new/replacement tube has.
How often should you clean and/or retension sockets? I clean them and check tension every time I remove a tube from the socket (unless I just did it very recently); and I pull them every 6 months and clean them if I haven't had them out in that period.
Please read/re-read the FAQ below. The vast majority of tubes I personally get back because they are "noisy" - are just fine when I recheck them. They were fine when they left and fine when they came back - hmm, could be contact issues!! No, not in EVERY case - but the large majority of them I believe.
Edits: 11/25/15 11/25/15 11/25/15 11/25/15Follow Ups:
A search for "fiberglass eraser" on amazon.com returns 72 results. Take your pick.
fiberglass pens can be found in auto stores or radio shack (I recall).
these have a bound bunch of FG filaments and the pen/holder has a
bottom twist to extend the bunch.
Really great on any corrosion/tarnish.
Bob
I don't think there is a good youtube video on how to clean and retension small 9 pin and octal sockets. Such a video would be useful instruction tool for many as a "video" is worth more than a thousand words. Anybody with the video and audio expertise to create such a video would get numerous high fives from posting a guide on youtube.
Hang in there Jim. You're one of the good guys and we do appreciate your endless patience and help. Especially me with my own stupid questions like whay aren't sockets dishwasher safe with or without tubes!!! Why does Jim get mad at me???
Happy Turkey day
charles
How does one retension tube sockets?
I am willing to do it if I can learn how.
A dental pick is the tool to use. Pull gently on each contact pair.
Eli D.
Thanks!
.
"I can't compete with the dead". (Buck W. 2010)
Thanks for the reminder Jim. I have work to do this weekend.
FYI, I recently discovered that G-U-M Go-Betweens Proxabrush Cleaners are great for cleaning tube sockets. The green ones work well with 7 and 9 pin sockets. I would suppose the blue ones would work best for 8 pins. And, Faber-Castell fiberglass eraser pens are great for cleaning tube pins.
Couldn't find Faber-Castell fiberglass eraser pen on Amazon. Is there another name for this. I did see some fiberglass pencil erasers but wasn't sure if this was the same thing and whether it is coarse fine etc. Thanks in advance for a reply. I have a lot of pins to clean!
Steve
I assume there are other brands. The F-C is what I have seen/used. It is multiple very fine strands of fiberglass in a plastic clutch style holder. I have only found them from overseas vendors such as Cult Pens.
http://www.cultpens.com/i/q/FC19593/faber-castell-glass-fibre-eraser-pen
Perhaps EPA or OSHA has an issue with the fine fiberglass dust they leave behind. Use a dust mask to be on the safe side and vacuum afterwards with a HEPA filter.
Good luck.
A pipe cleaner is OK for Octal socket contacts. Of course, a properly sized brush works too.
Eli D.
Thanks Jim!
NADA AQUI
--------------------------
Buy Chinese. Bury freedom.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: