Can you identify this unmarked EL84 tube?

[Armchair Bronco]

I'm trying to identify the brand of EL84's that shipped with my Chinese made Orange Tiny Terror. Unfortunately, there are no markings at all on these tubes. The manufacturing date of the amp was the last quarter of 2007, and the amp was delivered to Seattle in late January of 2008.

After 4+ months of daily use, mostly at the 7 watt setting, these tubes burned out so I bought some JJ's and some Sovtek's as replacements. These new tubes are nice, but I think I preferred the dirt and crunch of the original tubes. Since replacing the factory tubes my Tiny Terror has lost some of its mojo.

Someone on the OrangeAmps forum suggested I post some close-up pictures of these unmarked tubes on this site to learn about their provenance. Any help is appreciated.

http://img253.imageshack.us/img253/1020/tube6bi2.jpg

http://img355.imageshack.us/img355/9060/tube1mm0.jpg

http://img169.imageshack.us/img169/52/tube3gf0.jpg

http://img264.imageshack.us/img264/410/tube4gn6.jpg

http://img112.imageshack.us/img112/7265/tube7tn8.jpg

http://img178.imageshack.us/img178/489/tube5ni4.jpg

[Armchair Bronco]

I just found the following image on WIKIPEDIA (http://en.wikipedia.org/wiki/EL84). The last 4 tubes in this picture seem to be similar to mine. Ironically, the one that looks the most like it (4th from the right) is also unmarked...and the image description doesn't provide a summary of the tubes, either!

http://upload.wikimedia.org/wikipedia/en/5/57/El84.JPG

[rockon1]

Similar to an RFT (at least the mica is)but not quite. Got me but then again my thing is 12AX7's. Bob


http://i37.tinypic.com/10ylvn8.jpg

[brad347]

I would wager that they're the cheapest Chinese EL84 available, if they shipped stock with a Chinese-made combo amp.

[rockon1]

I would wager that they're the cheapest Chinese EL84 available, if they shipped stock with a Chinese-made combo amp.


True but if so interesting construction none the less. Bob

[VacuumVoodoo]

I would wager that they're the cheapest Chinese EL84 available, if they shipped stock with a Chinese-made combo amp.

Elementary, my dear Watson!

Shuguang EL84
http://i26.photobucket.com/albums/c149/VacuumVoodoo/Miscelanea/el84-shug.jpg

[rockon1]

Elementary, my dear Watson!

Shuguang EL84
http://i26.photobucket.com/albums/c149/VacuumVoodoo/Miscelanea/el84-shug.jpg

If so they significantly changed the design of the mica cut out and plate design. Not that they couldnt,of coarse, but both are different.Bob

[Groovey Records]

Try shuang el84's

[Armchair Bronco]

Try shuang el84's

It looks like Shuangs are branded under the "Golden Dragon" label, and these tubes seem to have the same design as mine. There's a Golden Dragon tube in the Wikipedia picture in post #2 above. On eBay, they're cheap: about $23 for a pair + $3.50 shipping.

However, I'm wondering if these will work with my Tiny Terror, which is a 7/15 watt class A amp. Here's the eBay blurb:

"This is an extremely popular miniature 9-pin (B9A) power output pentode designed for low to medium output audio power amplifiers. Push-pull ultra linear (class AB1) can be up to 17w. Also often used for single-ended class A operation in small low power amplifiers of a few watts. maximum rated anode dissipation is 12w. Matched Pair."

[brad347]

For one thing, yes it will work.

For another thing, your amp isn't really "Class A." They fudged the terminology because it makes for appealing marketing language. What your amp is is class AB that runs sort of like the "faux class A" Class AB of a Vox AC30... in other words, the tube is cut off for only a very small part of the cycle, but it cuts off nonetheless, therefore it is by definition Class AB.

Randall Aiken has a very informative article about the non-class-A-ness of an AC30 on his website.

[Armchair Bronco]

Man, I can see myself spending hundreds of dollars collecting various bizzaro EL84's from around the world in search of "that magical tone"...

Someone warned me that this would happen if I ever bought a tube amp -- I guess he knew what he was talking about! :crazy

[reaiken]

http://img253.imageshack.us/img253/1020/tube6bi2.jpg





Now that's a prime example of an amp that is running the screen grids way too hot!!! No wonder they only lasted 4 months...

Randall Aiken