Mesa STR 415

[STUART]

Anyone know who made the Mesa STR 415 6L6 GC

Just curious ...

They kinda look similar in structure to some Philips 7581a in my Mark iv

Stu..

 

[Russ]

According to the bottom of page 22 of the Mark IV manual the STR415 is a Sylvania 6L6. This would make sense why it looks like a 7581a.

 

[STUART]

For sure Russ ,
I recently bought a MkII C+ which has the Mesa STR 415 power tubes
Both types 7581a and STR 415 have the double getters etc giving an amazing tone , huge sounding with Boogie amps

 

[RR]

The original Mark I, II were practically design around the Sylvania's 6L6 (STR-415). You literally you could put these STR-415s without even biasing these Boogies and get optimum performance. If you use other tubes, you may have to have it rebias the amp to get optimum performance.

Sylvania's 6L6s are the "Holy Grails" of the 6L6s, just like Mullard EL34s are the "Holy Grails" of the EL34s.

 

[Shep]

do you know that the 105 c+ transformer was made for the 415's...higher plate voltage that the 415 could handle..so when ever you put new tubes in a 105 tranny they last half to what they are meant to..

 

[RR]

I was very cautious to mentioned about Sylvania's STR-415s because this topic on this board or any board for that matter may conjure up heated discussion because some guitarists feeling they're "missing out" and those who DO have have these STR-415s will have "bragging rights" and may getting this feeling they are "the privilege one" owning these tubes.

I remember MESA Boogie representative Mark Goodman during a Guitar Player Magazine Roundtable discussion, mentioned that the original Mark I, Mark II and Mark III (I think) sounded like crap (yes he used this word) if other tubes were used and not re-bias since these Boogies were fixed bias and were assumed these Sylvania tubes were the replacements.

 

[Russ]

The 415's were excellent tubes. I believe I read a post by Boogiebabies not long ago saying that they should last 10,000 hours.

 

[Elpelotero]

do you know that the 105 c+ transformer was made for the 415's...higher plate voltage that the 415 could handle..so when ever you put new tubes in a 105 tranny they last half to what they are meant to..

You're correct, but not 100% there. There are tubes out there which can in fact handle the entire voltage of the 105 PT. I forgot their names off the top of my head, but I'm pretty sure BB knows.

Russ, yes they do last 10,000 hours.

The closest thing to this tube nowadays is a GT 6l6 GE (I'm pretty sure i'ts groove tube). The GE=General Electric. Groove tubes bought the original factory equipment and are making these tubes again on that equipment.

 

[STUART]

Although the STRs are like hens teeth it would be nice to have a pair of em for spares :wink:

By the way any you guys know which preamp valves came stock with the Mk.IIC+,sure would be nice to try source some originals for the ones i have at the moment have no identification on em..

Grazio !!

 

[Russ]

With tubes rated for that kind of use you only would need a couple sets to last a lifeltime. I think there were Mullard M-series ECC83 preamp tubes that were also rated for similar longevity. Some Telefunkens were rated the same as well.