[macdane]

I've had a pair of Wright WPA-3.5 amps for 15+ years without a lick of trouble, but I'm still a total tube neophyte.

My wife bought me a new set of JJ tubes (2A3, 6SN7 & 5Y3 per amp) for Christmas and I expected this to be as simple as every other time I've swapped tubes. Not so. The tubes arrived yesterday and I found both 6SN7s and 5Y3s to be incredibly tight — difficult to seat fully in the sockets — while the 2A3s slip in so loosely I think a stiff breeze could blow them over. Right out of the box, everything sounded pretty good over the course of several hours of listening.

When I powered up the amps today, I got 2-3 seconds of music before the right channel died. I powered off again to check all of my connections, and the sound came back for maybe a second. After confirming all cable connections, I powered on again with the same result: the right channel amp only played for about 2 seconds, then again briefly when I turned it off.

I decided I'd swap my previous set of NOS tubes back in so I could listen a bit and then dig into this problem at a later date, but I now I can't get the 6SN7 tube out of that right channel amp. Any good advice for removing extraordinarily tight-fitting tubes without damaging anything?

Thanks,
Dane

[djbnh]

http://www.answers.com/mobile/Q/How_to_replace_tubes_in_a_tube_amp

[FullRangeMan]

WD-40

[macdane]

http://www.answers.com/mobile/Q/How_to_replace_tubes_in_a_tube_amp

Thanks, but replacing tubes is literally the only part of this stuff that I actually have experience with. My question is, what do you do when the "just pull on the tube and it will come out" part doesn't happen? Given the amount of force I've used and the amount of time I've put into this, I'm not sure there's a way to get this tube out without resorting to using some sort of tools as levers to pry between the socket and tube base. It's *that* tight. What I'm hoping for is some sort of advice on getting it out while causing a minimal amount of damage.

[macdane]

WD-40

That's something I have handy, FullRangeMan! As a tube newb, I don't want to do any unnecessary harm. With a substantial amount of effort, I can probably get this tube pulled out far enough to fit a credit card or two between its base and the socket ... is it then safe to spray a little WD-40 directly into that gap?

[FullRangeMan]

That's something I have handy, FullRangeMan! As a tube newb, I don't want to do any unnecessary harm. With a substantial amount of effort, I can probably get this tube pulled out far enough to fit a credit card or two between its base and the socket ... is it then safe to spray a little WD-40 directly into that gap?

WD40 is oiled and difficult to remove better dont use it.
Being the 6SN7 a bakelite base you should pull the tube by the base not by the glass.

[JerryM]

What a difference 34 minutes makes. 

[macdane]

WD40 is oiled and difficult to remove better dont use it.

Now I'm confused. You suggested WD-40 but don't think I should use it?

Being the 6SN7 a bakelite base you should pull the tube by the base not by the glass.

Yes, I'm making every effort to only apply force to the base rather than the glass. I'm not sure how to convey just how tight this is. Put it this way: if I didn't care about damaging anything, there's no doubt in my mind I can pick up the entire amp using just that one 6SN7.

[FullRangeMan]

Iam thinking that WD40 can collect dust in you sockets.
Do you think this tube was wrong position inserted?
Do you could raise the base of the tube with a slit screwdriver?

[macdane]

Iam thinking that WD40 can collect dust in you sockets.

That makes sense. I was just confused because it sounded like you recommended it and then recommended not using it.

Do you think this tube was wrong position inserted?

Boy, I doubt it. Isn't that why the center post is keyed, to prevent that? Even so, I'm always careful to get the key in the right position rather than simply relying on it only inserting in one position. Here's how little I know about tube gear: if by chance it's in the wrong position, would it still work? Because it worked really well yesterday.

Do you could raise the base of the tube with a slit screwdriver?

Unfortunately, that's what I think this will come down to. Although I'll likely enlist an additional set of hands so we can pry from two or three different spots at the same time to avoid harming anything. This is the sort of advice I need.

[FullRangeMan]

Insert a screwdriver may require careful due all that lethal DC Voltage and possible damage to the tube or amp.

As you said a old plastic credit card would be safer.

[galyons]

If you inserted the JJ 6SN7 with the keyway properly oriented, this should not have happened!   Typically,  JJ uses thinner-than-standard contact pins on their tubes.  This results in a looser than normal fit.  My guess is that you may have forced the tube in incorrectly, jamming the keyway in, but out of its groove.

Try rocking the tube out.  Grab the base and rock it side-to-side and front-to-back while pulling up. If that does not work...
Unlpug the amp,  Remove the other tubes.  Put something down such as a wood block or books, turn the amp over and set on transformers and the added support.  Make sure the amp IS NOT resting on the tube. Remove the bottom cover plate.

Get a flashlight and check to see if the tube is inserted correctly in the keyway. Likely NOT!




Since trying to remove by hand did not work.  Find a small wood dowel, chopstick cut flat at the wide part, or other improvised similar tool.  You will need to push the resistor soldered across the keyway to one side to get the dowel into the keyway. Grab a hammer, put the dowel in the bottom of the keyway and gently tap to push out the tube.  The key is lots of lightish taps, NOT brute force!! 

Caveat...you may damage and/or break the octal socket.  Easy to replace and the solder job to properly rewire is pretty simple. If you are careful you should be fine.

Cheers,
Geary

[djbnh]

This was also part of that article, I was trying to be helpful:
"To prevent cuts from breakage, and to keep the tube envelop clean, wrap dry cloth around tube. With a gentle rocking motion pull the tube you want to change from the socket." So after unplugging the amp and its ICs/ SCs, I would gently rock the tube for a while back and forth towards and away from you, then change rocking direction from side to side, the towards and away, all the while gently pulling up on the tube I'd use some type of frictions surface to help grip - like the rubber-esque material used to help open jars or line shelves.

Since you can get a slight gap between the amp socket and the bottom of the tube, perhaps you could slide a credit card atop the tube socket, and use a very thin screwdriver tip between the card and bottom of tube to help pry the tube up gently while rocking the tube. You could also try some Deoxit to help lessen the socket grip / break down socket corrosion - ProGold could be used but will not break down corrosion.

Hope this helps. Also, please post pictures if the amp, etc. TY

 

Thanks, but replacing tubes is literally the only part of this stuff that I actually have experience with. My question is, what do you do when the "just pull on the tube and it will come out" part doesn't happen? Given the amount of force I've used and the amount of time I've put into this, I'm not sure there's a way to get this tube out without resorting to using some sort of tools as levers to pry between the socket and tube base. It's *that* tight. What I'm hoping for is some sort of advice on getting it out while causing a minimal amount of damage.

[FullRangeMan]

The amp is pluged on the outlet?
One must not change tubes w/the amp pluged, as capacitors store electric charge for days.

[screener]

Just had a thought.

If you have some monofilament fishing line you could wrap it around  the base of the tube a few times. Do it twice and leave about 18".

Get something ruggard enough and tie  the 2 - 18" lines off keeping both tight. Try pulling it up while wiggling the tube.

Be Careful.

[djbnh]

If you inserted the JJ 6SN7 with the keyway properly oriented, this should not have happened!   Typically,  JJ uses thinner-than-standard contact pins on their tubes.  This results in a looser than normal fit.  My guess is that you may have forced the tube in incorrectly, jamming the keyway in, but out of its groove...

Cheers,
Geary

I'm guessing incorrect tube insertion, too.

[thunderbrick]

What a difference 34 minutes makes. 

 

[sfox7076]

Any sound at all before dying sounds like a different issue. Did the tube light up?  . Regardless, the chop stick method is the best to get it out if you can get underneath.

[dB Cooper]

Now I'm confused. You suggested WD-40 but don't think I should use it?

Welcome to our world.
Worse comes to worse, unsolder and replace the socket along with the tube. If it just won't budge, it may be easier this way. It may also be easier to separate them with the tube/socket more accessible. Obviously take a good crisp photo and/ or make a pictorial diagram so you can re-connect everything properly.

[FullRangeMan]

Welcome to our world.
Worse comes to worse, unsolder and replace the socket along with the tube. If it just won't budge, it may be easier this way. It may also be easier to separate them with the tube/socket more accessible. Obviously take a good crisp photo and/ or make a pictorial diagram so you can re-connect everything properly.

Thanks for contributing Copper you will be a good facilitator, that is well remembered, the socket may now be wider and may cause poor contact in the future.