Loose Tubes.... What is the best cure ?

N

NB-SK

· #2 · Aug 17, 2007

I'm not expert, but I would space out the connectors a bit by slightly bending them. That should solve the problem.

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greco

Discussion Starter · #3 · Aug 17, 2007 (Edited)

NB-SK said:
I'm not expert, but I would space out the connectors a bit by slightly bending them. That should solve the problem.

Thanks for the response.

I didn't think of doing that, but I would be uptight about the possibilty of breaking a pin on the tube or messing up a connection inside the tube....knowing my luck.

I looked at the tube retainers at the http://thetubestore.com, but a Blues Junior that I once owned had those and the springs would often rattle and buzz against the tubes...I was constantly adjusting with them to get rid of the noise. I really like the total metal enclosures, but I only see these used on the smaller tubes.

I wonder if this is a common problem with old amps , especially when the tubes are "hanging" down from the sockets.

Will see what others suggest.

Dave

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Hamm Guitars

· #4 · Aug 17, 2007

You could tin the tube leads with solder to make them a little bit bigger, hence tighter.

I'm not a tube expert by any means, but I would doubt that the tube would generate enough heat to soften the solder when it is in use.

I should add that I've never tried this myself, just a thought.

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greco

Discussion Starter · #5 · Aug 17, 2007

Thanks Hamm guitars

You guys are so creative !!

I have to learn to think "outside of the box"

Dave

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Gunny

· #6 · Aug 17, 2007

with the amp's power supply caps discharged, you can pull the tubes and re-tension the socket pins. A small pointed awl or equivalent tool is used to reduce the diameter, hence improving the gripping surface, of the pins.
I've known people to also take a round wound guitar string (not a new one) and run it through the pin to polish oxidation off the metal surface. If you try that, a shot of contact cleaner wouldn't hurt while doing it.

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Geek

· #7 · Aug 17, 2007

Hi,

Hamm Guitars said:
You could tin the tube leads with solder to make them a little bit bigger, hence tighter.

Not a good idea for power tubes (or ANY tube, but the mini's are less susceptible). The reason: seal stress. A tube's seal at the pins are designed so the metal and glass expand at the exact same rate. This is achieved when the whole unit warms up, as in normal operation. By applying solder heat to one point, you've made a point-of-expansion and until the joint cools to the same temp as the rest of the tube, air molecules are seeping in.

Cheers!

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Wild Bill

· #8 · Aug 17, 2007

greco said:
I have 2 old Fender tube amps and some of the tubes seem somewhat loose in their sockets.

I would prefer not to change the sockets, which I assume (possibly incorrectly) would be the logical approach to solve this problem.

Any other solutions to this problem that have lasted the test of time?

Thanks

Dave

Not meaning to be silly but if you haven't done this before please note that bending the pins is a tip only for the smaller miniature tubes. If you try it with the 6L6 output tubes they will probably break!

Preamp tubes should be held securely by metal shields with a spring inside that go over those 12AX7's. Old Fenders are notorious for having the sockets get loose for the big output tubes. Replacing the sockets is a PITA but a sure-fire cure.

You might consider buying those retainer spring caps like many Marshalls use. They can be mounted with the same screws that hold in the socket. You can get them from a number of places but a Canadian source would be:

http://www.thetubestore.com

I've put these in a number of old Fenders and they work just fine!

:food-smiley-004:

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greco

Discussion Starter · #9 · Aug 17, 2007

Wild Bill said:
I've put these in a number of old Fenders and they work just fine!

:food-smiley-004:

Thanks Wild Bill...no buzz/noise from the springs? (see post #3)

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Ripper

· #10 · Aug 17, 2007

greco said:
Thanks Wild Bill...no buzz/noise from the springs? (see post #3)

I've never had any buzzing or noise coming from the spring tube retainers. The other option is to try and tighten your pin slots in the socket themselves. You can actually buy a tool for doing it, but I use a jewellers screwdriver and gently slide it down beside the pin slot and push it tighter together. It works good and tightens up the hold on the tube itself.

Wild Bill is right, don't bend the pin on an octal style power tube (6l6, el34 etc) as you will probably end up with a broken pin and or tube base.

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Geek

· #11 · Aug 17, 2007

Hi,

If you get a buzz or ring, try a tube dampener. I don't mean those overpriced audiophool things, just a $1 silicone oil seal O-ring from your local Lordco or other auto parts store to fit around the tube

Cheers!

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greco

Discussion Starter · #12 · Aug 17, 2007

Geek...Thanks for all of the suggestions. I think I will go ahead with the spring retainers.

The retainers on the Blues Junior buzzed/rattled as the retainer was was designed to hold 2 tubes and the bar on the top of the tubes would shift.

Thanks again, to all.

Dave

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Ripper

· #13 · Aug 17, 2007

Don't hesitate on the spring retainers. I've got four amps here that use them and they have never been a problem. Good luck

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NB-SK

· #14 · Aug 17, 2007

The other guys are right: while bending the pins on smaller tubes like the 12ax7 is doable, it could damage a power tube.

Go for the spring retainers for a more permanent fix. The ones I've seen are mounted by using the same screws that hold the sockets.

If the springs are too long and/or the cap is too large on the power tube retainers, just bend the tongues on the caps so that it fits snuggly against the tubes to reduce the rattle. Don't know if there is a better solution, but this is what I did when I went from a large power tube to a smaller one on my 20watt amp.

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Soupbone

· #15 · Aug 18, 2007

Gunny said:
with the amp's power supply caps discharged, you can pull the tubes and re-tension the socket pins. A small pointed awl or equivalent tool is used to reduce the diameter, hence improving the gripping surface, of the pins.
...

This is how it is done and is usual but BE SURE the caps are discharged. Use a meter.
The tubes pins should be as straight and perpendicular as possible and there is a special socket for repairing ones whose spacing is out of whack.
You might keep a new regular socket around just for this purpose since those special ones are hard to find.
The reason being that it can make them hard to put in, it causes the spacing to be off, which is why the socket became loose in the first place.
You can also do it by eye (9 pin mini's only)but dont bend the tubes pins too much they break very easily.
If the octal tubes pins are bent. Dont chance it, leave them, they are hollow.

PS If you can hear the retainersprings rattling in there your not playing the amp correctly...TURN IT UP!...

)

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NB-SK

· #16 · Aug 18, 2007

Soupbone said:
This is how it is done and is usual but BE SURE the caps are discharged. Use a meter.
The tubes pins should be as straight and perpendicular as possible and there is a special socket for repairing ones whose spacing is out of whack.
You might keep a new regular socket around just for this purpose since those special ones are hard to find.
The reason being that it can make them hard to put in, it causes the spacing to be off, which is why the socket became loose in the first place.
You can also do it by eye (9 pin mini's only)but dont bend the tubes pins too much they break very easily.
If the octal tubes pins are bent. Dont chance it, leave them, they are hollow.

PS If you can hear the retainersprings rattling in there your not playing the amp correctly...TURN IT UP!... )

Of course, but by rattle, I meant when you touch the tubes. It would think it's safer to have the retainer properly fitted than not.

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Adicted to Tubes

· #17 · Aug 18, 2007

Change the tube sockets!You are wasting your time trying to re-tension the pins and fender's are notorious for poor contact in this area.Do not use ceramic tube sockets,as they are poor quality unless you get the new style fender ones used in some new model production amps.They have a 'memory' on the pins and will last longer than the originals.Tube retainers are a band-aid at best.Ask any tech who has tracked down crackles and low output power on an old fender amp.
I use Belton tube sockets with tremendous success.If you cheap out and get lazy,you will reap the penalty.Do the job once.

www.claramps.com

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