What are STR 440 EL34's?

I have not been able to gain much information on these tubes.

Does anyone know anything about these? I bought them probably in the early 90's. Some people say they are 6L6 Chinese junk relabeled but I don't really believe that.

Also what other make/brand would they compare to because I am looking to experiment and don't want to duplicate these.

Thanks in advance

Mesa sells the EL34 STR-447, 440's are 6L6

http://www.watfordvalves.com/product_detail.asp?id=1811

Yes they are made in china, and yes they are junk. Tube Amp Doctor (TAD) sells the same tube too.

I know the STR 440 is suppose to be a 6L6, but these are clearly marked EL 34 STR 440

Thats the whole confusion here on my part. What is this tube?

http://forum.grailtone.com/viewtopic.php?t=30109

You mean these?
These are from the early 90's, at least that's when I bought them.
Haven't used them in years, don't recall what they sound like.
Probably not great, since I haven't used them in years.
They both have the label, I turned one over to see more details.
Russian? Chinese? Expert opinions?

Those are them. I read the previous thread and people don't seem to know or think they are 6L6's or reject 6L6's? To me they don't look like 6L6's

My bro just picked up a MKIII Blue stripe Simul-Class and it came with the old STR415's and the STR416's. Now those are some big a$$ el34's!! What would replicate close to those?

They look Chinese to me. :idea:

http://forum.grailtone.com/viewtopic.php?t=30109

Yeah, I don't buy the statement that they were originally 6L6, relabeled to EL34/6CA7, that sounds crazy, they look nothing like a 6L6.

The confusion lies in the designation "STR-440".
This is the name of the current Mesa 6L6.
The tubes pictured are EL-34s from 20 years ago.
Mesa called these 20 year-old tubes STR-440s, way back when.
People are confusing these old EL-34s with new 6L6s.
Different tubes, same name, twenty years apart.
It's like if Ford resurrected the "Edsel" name, and stuck it on a new car.
Simple, n'est-ce pas?

those plastic spacer things on the top mica are typical of Chinese tubes if that helps...

Here are mine

The square getters on the tubes would indicate they are Chinese. The old Mesa 12ax7A I have share the same getter design which are Chinese tubes.

I got the old tubes back from the person I sold my Mark III too. There was a set of the large bottle EL34/6CA7 made in USA (probably Sylvaina, they were STR410 and the 6L6GC was STR 415. ). The skinny replacements that I had are also marked as EL34/6CA7 just like the pictures above, except they have a single thick Halo getter, tube is marked as STR440. As I recall, they red plated sooner than the original large bottle USA branded tubes.

I kinda suspected that. The give away is the plastic spacer and the square getters. Now why is it that the Chinese 12AX7's made around the same time are some of the best sounding tubes you can put in a Mesa?

Now the BIG question?????????????????????????????????????

STR450's? Mullard,s? or the infamous Sylvania EL34 6CA7's

Big Decision.

Sylvania EL34 6CA7's <----- These!

DJPattP said:

I kinda suspected that. The give away is the plastic spacer and the square getters. Now why is it that the Chinese 12AX7's made around the same time are some of the best sounding tubes you can put in a Mesa?

Now the BIG question?????????????????????????????????????

STR450's? Mullard,s? or the infamous Sylvania EL34 6CA7's

Big Decision.

Click to expand...

I have 10 of those Chinese 12ax7A. Each of them only has 3 months of use on them (dating from 1987 to 1997 which is the last time I bought tubes for the Mark III). When I was in a band it took 3 to 4months to burn up the EL34 (subsequently the 6L6 running in parallel with it at times) with my Mark III. Since I needed to replace the power tubes I decided to change all tubes at the same time (did not do it every time). I did keep some of them just in case they were still good. They sound the best in the Mark V. Not even fizzy like some have indicated. No amp noise at all, super quite. The Mesa version of the JJ tube would be similar to hum, hiss, etc. but they sound pale in comparison. As for all of the Tung Sol, Mullard (re-issue), and EH 12ax7, they work fine without any noise issues in the Mark IV, so I have plenty of tubes to last a long time. I did compare the Penta Labs tube which is identical to the old Mesa tubes, but they then to be noisy and break into harmonics easily. They do not compare to the tubes I bought in the 80's and erly 90's. Any of the new sensor preamp tubes when placed in (V3, V4, V6) I get that ac hum out of the speaker (no signal input). The only exception V7 which also uses an AC source voltage for the heater is quite with the Sovtek LPS. I have tried others with less than favorable response.

You mentioned getting a bias probe, so I thought I would suggest the one that I use. The "Quadstage BiasPro MQ10", which has a built in meter, and I got four 8-pin and four 9-pin probes. I also have the "Quadstage BiasPro Q10", which requires a separate meter. Both allow checking four tubes at once, and both have worked well for quite some time now.

http://www.asharpfretworks.com/5543.html