New tubes, red base 6l6 STR448 mix w/ SR440 for dual rec 3ch (non multi wattO

[sonny7]

I need 2 power tubes for a dual rec, 3 channel non multi watt. I blew a tube ( someone plugged speaker cable into wrong jack and the 3rd power tube blew). The tubes were basically new and I dont want to replace all 4 ( both sets) due to the insane price increase. I ordered 2 6l6 STR448 ( its all they had) and the tube has a red base and the bottle ( glass ) is taller than a str 443 or 440. Is it "bad" to use these str 448s with the smaller glass str440?

Mesa told me this is the 6l6 they are pushing ( researched its a TAD tested by Mesa) This amp is from 2000 nd I dont want to " push it" or mess it up Its been loyal and I need it now for recording


any info is appreciated

thanks

 

[tbonesullivan]

Are the tubes the same rating as the other tubes you have? Also, what exactly happened to make the tube blow? It's rare that a tube wwill blow without taking a fuse and possibly some other components with it.

 

[domct203]

I need 2 power tubes for a dual rec, 3 channel non multi watt. I blew a tube ( someone plugged speaker cable into wrong jack and the 3rd power tube blew). The tubes were basically new and I dont want to replace all 4 ( both sets) due to the insane price increase. I ordered 2 6l6 STR448 ( its all they had) and the tube has a red base and the bottle ( glass ) is taller than a str 443 or 440. Is it "bad" to use these str 448s with the smaller glass str440?

Mesa told me this is the 6l6 they are pushing ( researched its a TAD tested by Mesa) This amp is from 2000 nd I dont want to " push it" or mess it up Its been loyal and I need it now for recording


any info is appreciated

thanks

If the amp was run without a speaker load to the point of blowing power tubes it needs to be check by a tech. Even if the fuse blew, and replacing it with the right fuse restored power you could have internal damage to the amp, with the screen resistor being a common item. If the screen grid circuit is open, the tube in that position is now not able to run and is just sitting there with the heaters glowing but not passing audio, negatively effecting tone and feel.

Any current pair of 6L6GC from Mesa will be fine, just make sure you change the pair.

Your amp uses its power tubes in pairs. Either direction you count the tubes the 3rd one is part of the inner pair, change power tubes 2 & 3. Power tubes 1 & 4 are the outer pair.

Don’t just change tube #3, chances are the failure there has over stressed its counterpart in the pair as well.

I still recommend the amp be checked by a tech.

Dom

 

[sonny7]

If the amp was run without a speaker load to the point of blowing power tubes it needs to be check by a tech. Even if the fuse blew, and replacing it with the right fuse restored power you could have internal damage to the amp, with the screen resistor being a common item. If the screen grid circuit is open, the tube in that position is now not able to run and is just sitting there with the heaters glowing but not passing audio, negatively effecting tone and feel.

Any current pair of 6L6GC from Mesa will be fine, just make sure you change the pair.

Your amp uses its power tubes in pairs. Either direction you count the tubes the 3rd one is part of the inner pair, change power tubes 2 & 3. Power tubes 1 & 4 are the outer pair.

Don’t just change tube #3, chances are the failure there has over stressed its counterpart in the pair as well.

I still recommend the amp be checked by a tech.

Dom

Thanks Dom. The amp does work and sound great, But I think I am going to have it checked ( just need to find someone lol). The vol (pot) on the clean channel has been needing replacement for sometime. Where the tube sits that blew out, there are burn marks . What actually happened was that the speaker cable was inserted into one of the "external channel channel switching " jacks. It ran blew 2 fuses then third time tube blew.

 

[domct203]

Mesa’s are tough, but after 3 fuses you should definitely have it checked. You are lucky that you didn’t destroy the output transformer.

That black carbon on the tube socket needs to be cleaned off, it’s carbon and it’s conductive, you don’t need a short across pins of the socket.

If you are going to clean it yourself you need to remember that the amp will store up to 450 volts in its power filter capacitors, even for days while unplugged. That’s enough voltage to stop your heart, and it’s located in the tube sockets.

Do not use anything conductive like a wire brush. A good spray or two of a quality contact cleaner like DeOxit and some wiping with a soft cloth may do the trick. Maybe a q-tip or two for tight spots. To clean the inside of the socket spray some DeOxit on the tube pins and work the tube in and out a couple of times.

Let the amp dry thoroughly with the tube out before playing it, depending on how much cleaner you had to use it should be dry in 30 mins or so.

Be safe.

Dom