Stock Dual Recto 6L6's

[the human timebomb]

I'm putting the old stock tubes back in my dual rectifier. Since retubing they have been mixed up, two of the power tubes are slightly bigger than the other two. Where do these go? Also are the 12XA7 preamp tubes all exactly the same?

Cheers!

 

[tele_jas]

Not to insult you, but are you sure it's a 6L6 or that the others are 6L6's? Rectifier tubes are sometimes bigger too and EL34's are smaller in size too. Make sure it's a 6L6.

The only reason I say to check your tubes is before I knew too much about tubes I put rectifier tubes in the power tube slot of my Twin.

 

[the human timebomb]

Nah all 4 power tubes are 6L6GC STR 440's, 2 of which are slightly bigger. It's the ones that came with the amp too. :?

 

[jbird]

All the power tubes should be the same size! And you should have two matching pairs, or all matching! There may be one pre-amp tube labeled SPAX7 for the V1 position.

 

[redmax61]

You may be referring to the Rectifier tubes. Mine has 5U4G's which are slightly larger than the stock 6L6's and have a "bowl" shaped top.

 

[the human timebomb]

Thanks for the advice but I'm aware of the difference to the rectifier tubes which are in place. I thought the power tubes should all be the same size too, but apparently you can get STR 440's in 2 sizes. Hahah wtf is going on!?

 

[Dale B.]

Nah all 4 power tubes are 6L6GC STR 440's, 2 of which are slightly bigger. It's the ones that came with the amp too. :?

They're all the same, but the bottles are slightly smaller on the two that you mention. This won't have a negative effect on the performance of the tube.

Dale

 

[axwielding1]

I bought a matched set of STR454's awhile back, and one tube is slightly longer than the other. The plates are the same, and they sound great. Just one bottle is longer than the other by about 1/4"...
Just the glass cut I guess...
ax. :twisted:

 

[brianf]

Just a guess but one of those tubes may be a chinese STR440 and the other Russian???


brianf

 

[cnumb44]

I noticed the same with the 6L6s I got in my LSC. All Mesa tubes and there were 2 slightly different sizes. I'd say differnet manufacturer, but they are all tested by Mesa to the same spec, so not to worry.

 

[Dale B.]

It's not that they're loading power tubes tubes that are made from different manufacturers into their amps. The tube manufacturers are just using two different bottle sizes. I've seen this with SED's and the Ruby 6L6GCM-STR's. I believe the STR-440's are the same thing as the Ruby 6L6GCM-STR or it's something very close. I know they're both made at the Shaguang factory.

Just look at the plate, getter/s and the shape of the insulating spacers. If everything looks the same, then you have the same tubes, but with different bottle sizes.