Mesa 6L6GC STR-440 (don't fit in all the way)

[Sanctuary]

I got new tubes for my Mark IIC+ ( Mesa 6L6GC STR 440s) and when I put them in, I noticed that I cannot stick them in all the way unlike the previous 5881 tubes that were there previously. Is this normal?
They work and sound great though.

 

[Mongo1]

Is it binding on the center post?

 

[Sanctuary]

I don't understand your question.

The pins don't go all the way in and I don't know if I am supposed do something other than just sticking them in so that they fit.
Is this normal? I've look at other amps and it appears to be normal that there is maybe half an inch of the pins sticking out from the socket.

 

[Mongo1]

I'm just asking if you can see what/where the binding is occurring?

 

[MrMarkIII]

Is it binding on the center post?

The center post has a key which only fits the tube socket correctly one way.
The metal pins will fit the socket correctly only if installed with the correct orientation.
There are many videos on YouTube demonstrating proper tube installation.

 

[Mongo1]

I don't understand your question.

The pins don't go all the way in and I don't know if I am supposed do something other than just sticking them in so that they fit.
Is this normal? I've look at other amps and it appears to be normal that there is maybe half an inch of the pins sticking out from the socket.

The tube should sit flush against the socket when properly installed. I don't have any tubes that show a 1/2 inch of pin when they are installed. It would make sense that the tube would not go all the way in if it were not oriented properly because it would be hitting the key/ridge. You stated that it is working, so I'm thinking that it would need to be oriented correctly for that to be the case.

My original question about binding on the center post was in hopes that maybe the manufacturing tolerances were a tad big on the center post and it was a tight fit.

 

[Sanctuary]

In the end I took them out and put the old Sovtek 5881/6L6WGC in there. I guess my amp wasn't made for 6L6GCs. It wasn't normal that they didn't fit flush. Are the Sovtek 5881/6L6WGC good tubes? They were in them when I bought it.

 

[JOEY B.]

The real problem might be the cockeyed pins on the STR-440 tubes. It becomes very evident when you pull out some of the Chinese tubes and install USA NOS Sylvania, or Russian SED =C= power tubes. The older, tan power tube sockets really show the manufacturing faults.

 

[Halfstack]

On my Road King II, none of the 6l6 tubes go in all the way. The rectifier and EL34s do, but not the 6L6's. I called Mesa and they said that it was common and not a problem for 6L6s. So I believe the "tubes should be flush" statement may be wrong...according to Mesa anyways..

I know this thread is old but I wanted to get this info out there as I couldn't find any help when I was searching the internet at the time I needed the info.

 

[JOEY B.]

On my Road King II, none of the 6l6 tubes go in all the way. The rectifier and EL34s do, but not the 6L6's. I called Mesa and they said that it was common and not a problem for 6L6s. So I believe the "tubes should be flush" statement may be wrong...according to Mesa anyways..

They should have said "This is a common complaint for the STR-440". Look at the parallelism of the power tube pins to each other. Then look to see if they are perpendicular to the tube base. Forgive my terminology, as I read blueprints and did machine work for many years. :roll:

 

[Halfstack]

On my Road King II, none of the 6l6 tubes go in all the way. The rectifier and EL34s do, but not the 6L6's. I called Mesa and they said that it was common and not a problem for 6L6s. So I believe the "tubes should be flush" statement may be wrong...according to Mesa anyways..

They should have said "This is a common complaint for the STR-440". Look at the parallelism of the power tube pins to each other. Then look to see if they are perpendicular to the tube base. Forgive my terminology, as I read blueprints and did machine work for many years. :roll:

It might be a complaint, but if functionally it doesn't matter then.....what does it matter - do these complainers know something Mesa doesn't? If the pins are bent should I try to straighten them out? Just trying to get the best out of my amp and I want to do things right. Are the EL34 STR-447 made in the same place as the STR-440s because I don't seem to have a problem with those. I've gigged with this amp for the last 2 + months every week without a problem.

 

[JOEY B.]

On my Road King II, none of the 6l6 tubes go in all the way. The rectifier and EL34s do, but not the 6L6's. I called Mesa and they said that it was common and not a problem for 6L6s. So I believe the "tubes should be flush" statement may be wrong...according to Mesa anyways..

They should have said "This is a common complaint for the STR-440". Look at the parallelism of the power tube pins to each other. Then look to see if they are perpendicular to the tube base. Forgive my terminology, as I read blueprints and did machine work for many years. :roll:

It might be a complaint, but if functionally it doesn't matter then.....what does it matter - do these complainers know something Mesa doesn't? If the pins are bent should I try to straighten them out? Just trying to get the best out of my amp and I want to do things right. Are the EL34 STR-447 made in the same place as the STR-440s because I don't seem to have a problem with those. I've gigged with this amp for the last 2 + months every week without a problem.

The 447's are Russian tubes and the 440's are Chinese made. DO NOT try to straighten out the pins. This is a manufacturing defect that cannot be resolved by the end user. Functionality would become an issue if some conductive material became in contact with the exposed pins. This is not a likely scenario, but anything is possible. If you doubt my word, try the 447 in all the power tube sockets. With the power off, of course. :wink:

 

[Halfstack]

The 447's are Russian tubes and the 440's are Chinese made. DO NOT try to straighten out the pins. This is a manufacturing defect that cannot be resolved by the end user. Functionality would become an issue if some conductive material became in contact with the exposed pins. This is not a likely scenario, but anything is possible. If you doubt my word, try the 447 in all the power tube sockets. With the power off, of course. :wink:

Ah yes that does make sense. I have been hearing that the Chinese were supposed to be better than Russian tubes but maybe that is just certain ones. Are there any aftermarket 6L6's of the same or better reliability that actually fit right?

 

[JOEY B.]

Are there any aftermarket 6L6's of the same or better reliability that actually fit right?

SED Winged =C= They used to be called MESA STR-454's.