Does anyone know about Mesa 440 EL34/6CA7's?

[Russ]

There are some sitting in this Carvin X100-B in my practice space right now. How do these stack up to other EL34's? Should I be interested in them? I don't really want to take them out and try them in my own amps unless there is something about them I should at least have experienced. Who made these EL34/6CA7's?

 

[Restless Rocks]

Hey Russ, the STR-440 is Mesa's current 6L6 issue. I tried a set in my Mk III and am fairly impressed by them a real nice full tone with great bass and not such fizzy highs. The STR-447 is the current EL-34 version from Mesa. I replaced a set of Svetlanas in a guys JCM-800 with these and he was real impressed; I thought they sounded pretty decent myself and I'm not really a big marshall fan. This fellow said he'd tried most everything he could find and liked them so much told me to get him another set in about 4 months. Go figure? Don't know who made em.

 

[Buddy]

I recently retubed my mark III simul with those power tubes , also a set of the mesa 12ax7a's preamp tubes . I pulled the pre's all except he reverb driver and replaced them with some rca used . I was amazed at the improvement . Just for fun I installed the original 415's & 417 's . Little a/b comparison . Verdict ? 440 / 447 "s are not by any means a bad choice for the power section . Pretty good actually ( to my 47+ old ears ).
The soviet preamp tubes are not preferred for critical tone duties .
Hopefully the tinnitus will wear off soon

 

[Russ]

Here are some pics of the tubes in question:

This webcam sucks for taking pics but it is the best I can do right now. My digital camera is broken. I only have this because I managed to dig it up out of the computer parts box in my garage. I forgot I even had it. It's better than nothing I guess. At least everyone can see what I am looking at now. Like I said, Mesa STR440 EL34/6CA7 .

 

[Buddy]

That's weird , my el34's look similar , have black lettering ,do not flare from the base and are labeled 447 .

Boogie could'nt (shudder ) have mislabled the tubes ?

 

[Russ]

These actually don't flare. It might be the lighting deceiving you. Like I said this web cab kind of sucks.

Note the double getters on these tubes look squarish but with mild folds towards the ends with these little like crimped lines around the edges. Then in the middle of the getters' square it is similar to the typical preamp disc getter that is saucered.

The 447 has a ring getter.

 

[Buddy]

Yeah , Its a different tube ...Oh well too much stress .
Time for a beer . 8)
I always thought the str designation had to do with the type of tube .
Do we have a paradox ?

 

[Russ]

I think we got a pair o' tubes that aren't the same. :roll:

 

[Russ]

This thread talked about them a little. But there was only 3 replies and nothing identified the tubes.








^What happened to the link? :shock:

 

[Russ]

Here are some pics of the same model of tube I just snagged off an auction in Japan:

As you can see, the ones above are matched for green. The ones I have are a pair of red and a pair of yellow.

 

[Russ]

If you look at the getter style it is like a mixed style that is both semi washboard and semi saucer.

Also the plates are welded unlike the 447.

 

[Buddy]

I found a reference for the 440 el34 in the simul 295 owners manual .
These look similar to the mullard reissue .

 

[Russ]

Based upon the getter itself comparing it to some GT12AX7's they appear to be Chinese because the 12AX7's have the additional metal stabilizer that are known to be in Chinese 12AX7 tubes. It very well could be that they are Chinese because the 420 was a Chinese tube that Mesa used and I am assuming that these tubes were bought around the same time because the amp they came out of has sat for years unplayed. There is actually one that though matched to one with the washboard looking plates has a heavy ring getter. I am assuming that the pairing may have been made at a transitional time in manufacture/batches by Mesa.

Just out of curiosity I pulled out some older EL34M's that I have and they are identical getters. Now that makes me believe that the whole getter construction idea is out the window unless the EL34M's that I have are actually Chinese. They could be anything though because I didn't buy the EL34M's. I received them in an amp and I kept the good pair of the quad when one went south. When I had the amp retubed and rebiased for the new set of tubes (Marshall amp) I just asked that the amp sound the same when it came back. It was outfitted with E34L-CZ's when it returned. It sounded as far as I could tell at the time the same. This throws everything for a loop.

Now, I really need these tubes identified because it is making me question my thoughts on certain tubes. I mean I know some decent tubes came out of China but then again some of the stuff was pretty shoddy. I am just wondering if I inadvertently sold some amps over the years because of a tech not picking tubes that agreed with my ears. I know that the 420 sounds great for a 6L6 and that it came out of China. I am just wondering how many Chinese EL34's had as good of standing amongst their peers. I am aware that the STR-EL34B is a good EL34 but I was under the impression that there hadn't really been any great Chinese tubes in general. Maybe it was a discriminatory thing on behalf of my tech? I dunno, I am beginning to rethink things now. The general concensus is that Chinese tubes suck. There again, Mesa has been choosing to use them for quite a while, not that I care for some of Mesa's choices.

 

[Russ]

I found a reference for the 440 el34 in the simul 295 owners manual .
These look similar to the mullard reissue .

If my EL34M's were older Mullard reissues then yes they look identical.

The newer Mullard reissue looks identical to the old Mullard XF2 and is touted as an XF2 clone. The XF2's had dual ring getters.

 

[Russ]

Well, I ran the tubes through the tester today and they all tested great. In fact, they were as I would expect from new tubes actually. The GT preamp tubes in the amp all tested very strong and the PI was balanced at that. The STR440 EL34/6CA7's all tested almost 100% with adequate warming up time. I think I might see if I can buy this amp. They have been selling for about $250 lately and it has about $140 in fresh tubes in it. Now I just gotta plug her in to see if she is worth $110. I mean I could always put some crap tubes in it to sell it later. It has the hot rod mod already done (or so the sticker says on the chassis). I might be able to turn it for a couple bucks and get to see what these were all about in the meantime. From what I have read they are much like a modded JCM800 with a graphic EQ and a couple push/pull knobs on the lead drive and master that act much like a Boogie. It is 2 channel with variable power that you can cut to 50 and 25 watts from 100. I know it'll never be a gem but it might be a good backup for someone or a great giggable amp for those gigs where you don't want to take nice gear.

 

[Nigel.Wambuto]

The STR-440 EL34 was indeed Chinese. Mesa began using it when their supply of Sylvania 6CA7s (aka STR-416s) was finally depleted.

 

[Shep]

i have some 416's and some 440 ca7's.. both are great.. they sound like a copy.. but just like the 420's they probably won't last as long..