The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    Tube Socket Maintenance

    Share

    arledgsc

    Posts : 330
    Join date : 2012-11-30
    Location : SF Bay CA

    Tube Socket Maintenance

    Post by arledgsc on Sun Dec 28, 2014 7:06 pm

    I returned from holiday break after being out of town for about six days.  This morning the right, front KT-120 in my ST-120 wasn't setting up properly on bias adjustment and I even slightly wiggled the tube in the socket to see if bias jumped (didn't see any large jumps).  I got it close at the 12 o'clock bias pot position and recheck bias later on and was on the low side while the other tubes were normal at their customary 10-10:30 bias pot positions.  But I noticed the heater glow on the right, front tube was dimmer than the other KT-120s.   Swapped tubes and the problem followed the position/ socket.  So took the amp down to adjusted the right channel sockets pin tension - especially the heater pins.  That seemed to help and restore normal operation.   Other ohmmeter checks like measuring the 10 ohm cathode resistors, heater wiring, etc looks OK.

    Besides re-tensioning the pins are their any cleaners that are safe and effective?   Is there any other maintenance you can do to help prolong the life of the tube sockets?  I have to admit I auditioned a few sets of tubes early on but not for a while now.  The amp is exactly 2 years old and NEVER sounded better after the socket tune up.  What a beast!!!    Thanks for any tips and tricks, Scott

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Tube Socket Maintenance

    Post by sKiZo on Tue Dec 30, 2014 1:09 am

    I use pipe cleaners. A couple drops of D5 on one so it's just damp, do the old in and out a couple times to spread the cleaner evenly, then insert and pull the tube itself a couple times to polish up the mating surfaces. Pull the tube and use another pipe cleaner with a bit of ISO on it to remove any excess cleaner and you're golden.

    Used tubes can have a lot of corrosion on the pins - a bit of 00 steel wool with D5 and otherwise the same steps to spiffy them up. Even NOS that's been collecting dust for a couple decades can benefit from a quick cleanup. New tubes SHOULD be clean, but who knows?

    Been said before, but worth repeating. Never rock the tubes in the sockets and not a bad idea to at least eyeball the socket fingers any time you switch tubes. Pin diameter can vary a bit from brand to brand. I know my TungSols can stretch the sockets to where most KT88's are too loose. I've got a nice little ceramic screwdriver that's perfect for re-tensioning, so I just go thru the sockets when doing a swap. You're not really bending the metal enough to worry about stressing it.

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: Tube Socket Maintenance

    Post by PeterCapo on Tue Dec 30, 2014 6:13 am

    Interdental brush and 99% isopropyl to clean the tube socket contacts, maybe some compressed air to blow the isopropyl out so there's less chance of dissolved/suspended grunge remaining in the contacts.

    I had similar issues with my new tube socket(s) after about a year of use.

    corndog71

    Posts : 444
    Join date : 2013-03-19
    Location : It can get windy here

    Re: Tube Socket Maintenance

    Post by corndog71 on Tue Dec 30, 2014 11:10 am

    Belden sockets are my preference.  They have superior grip compared to ceramic sockets.

    arledgsc

    Posts : 330
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Tube Socket Maintenance

    Post by arledgsc on Tue Dec 30, 2014 11:30 am

    Thanks... I have a game plan and thanks for the good information.

    PeterCapo

    Posts : 380
    Join date : 2008-12-05

    Re: Tube Socket Maintenance

    Post by PeterCapo on Wed Dec 31, 2014 12:17 am

    corndog71 wrote:Belden sockets are my preference.  They have superior grip compared to ceramic sockets.

    Link?

    Thanks.

    Captain Coconut

    Posts : 209
    Join date : 2009-10-13
    Age : 64
    Location : Great White North

    Re: Tube Socket Maintenance

    Post by Captain Coconut on Wed Dec 31, 2014 8:45 am

    I just bought some Beldons. The pins are so tight that I can't get tubes to go in. I guess I'll need to practice some more.

    Mine were purchased from Parts ConneXion. I think Jim McShane may have them as well.

    corndog71

    Posts : 444
    Join date : 2013-03-19
    Location : It can get windy here

    Re: Tube Socket Maintenance

    Post by corndog71 on Wed Dec 31, 2014 11:07 am

    Octals
    https://www.tubesandmore.com/products/P-ST8-209MIP

    9-pin
    https://www.tubesandmore.com/products/P-ST9-601

    sKiZo

    Posts : 1285
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Tube Socket Maintenance

    Post by sKiZo on Wed Dec 31, 2014 3:02 pm

    Belt on sockets ... I hear all the cool audiophiles are wearing them ...



    I wouldn't try forcing a tube if it's a tight fit as you can stress them and cause vacuum leaks. I use a small nail set tool to stretch mine a bit if they're fighting me. Doesn't take much ...

    GreggW

    Posts : 55
    Join date : 2015-07-15

    PM

    Post by GreggW on Tue Nov 24, 2015 7:51 pm

    As a preventive maintenance measure, how often should tube sockets and tube pins be cleaned? I'm not a tube roller, except for rectifiers  Neutral , and just want to avoid problems related to corrosion. About two months ago, DeOxit was used to clean sockets and all tube pins in the ST-120.

    Jim McShane

    Posts : 154
    Join date : 2011-10-19
    Location : South Suburban Chicago

    Re: Tube Socket Maintenance

    Post by Jim McShane on Tue Nov 24, 2015 8:27 pm

    Captain Coconut wrote:I just bought some Beldons. The pins are so tight that I can't get tubes to go in. I guess I'll need to practice some more.

    Mine were purchased from Parts ConneXion. I think Jim McShane may have them as well.

    Yes I do, thanks for the mention. And I recommend them highly. I wish the octals were available in a smaller diameter, but the 9 pins fit a lot of places.

    GreggW

    Posts : 55
    Join date : 2015-07-15

    PM interval?

    Post by GreggW on Wed Dec 16, 2015 6:31 pm

    Looks like general consensus on process of cleaning tube pins and sockets. What is the recommended interval to clean tube sockets? I'm a believer in periodic maintenance, but I'd rather be listening to the ST120 than working on it!

    Thanks,

    Gregg

    Tubes4ever

    Posts : 59
    Join date : 2015-07-14
    Location : Star, Idaho

    Re: Tube Socket Maintenance

    Post by Tubes4ever on Wed Dec 16, 2015 9:33 pm

    Gregg,

    Whenever you change tubes you should tighten up the socket contacts and clean them.
    You and I like to roll rectifiers tubes and I've had to retighten that socket much more often. Otherwise I have issues with the heater not lighting up.

    I have an ST70. My EL34s never leave the socket and I've had no trouble with those.

    Tim

    GreggW

    Posts : 55
    Join date : 2015-07-15

    Re: Tube Socket Maintenance

    Post by GreggW on Thu Dec 17, 2015 9:42 pm

    Appreciate the info. My ST 120 is working perfectly and sounds great. In 3-4 months, I'll clean the rectifier pins and sockets. Just for grins, I've ordered a Mullard 12AT7 equivalent for the driver board from Jim McShane, a Christmas present to myself...

    Tubes4ever

    Posts : 59
    Join date : 2015-07-14
    Location : Star, Idaho

    Re: Tube Socket Maintenance

    Post by Tubes4ever on Thu Dec 17, 2015 10:40 pm

    Gregg,

    Planning on changing the 5v3A to something else in 3-4 months?  What's the next tube? Question

    GreggW

    Posts : 55
    Join date : 2015-07-15

    Re: Tube Socket Maintenance

    Post by GreggW on Fri Dec 18, 2015 2:10 am

    Hope to reinstall the same 5V3A that's in the amp now. If it ain't broke, I'm not gonna fix it! But if something new comes along, well, maybe.....

    Tubes4ever

    Posts : 59
    Join date : 2015-07-14
    Location : Star, Idaho

    Re: Tube Socket Maintenance

    Post by Tubes4ever on Fri Dec 18, 2015 2:14 am

    If you don't remove the 5V3A, there shouldn't be any need to clean the socket. Removal and reinstallation flexes the contacts.

    Sponsored content

    Re: Tube Socket Maintenance

    Post by Sponsored content Today at 6:34 am


      Current date/time is Sun Sep 25, 2016 6:34 am