help identify this "cleartop 6550"

[alexg]

A seller in Singapore is selling a quad of Svetlana and a quad of this tube that even he does not know what brand (tubes on the left):



Can somebody please help me identify this, I emailed the seller to email me the markings on the boxes, maybe I can deduce the make from the box (he has not replied yet).

Thanks.

[danFrank]

They are Svetlana 6550's; the OLD Svetlana. Now they are called "Winged C" 6550's. These are NOT the ones made by Sovtek (Reflektor, I think) or Mike Matthews.
The ones you have there are the 6550B version or maybe the 6550A version that they sold 10-12, maybe 15 years ago. This was the type of getter that old Svetlana used back then. I also have a pair of EL34's by them that look this way.

Watch out as some of these have BAD bias runaway potential in some circuits. I had a pair and they never could bias properly in my Dynaco Mark III's. Old US 6550's never had this problem with my Dynaco amps.

Daniel

[Zibi]

Tronal?
http://www.jogis-roehrenbude.de/EL34...ory-Seite3.htm
http://www.jacmusic.com/KT88/kt88.htm
Tamington?
http://www.wiwitubes.com/pic/tube/RMT6550.jpg
Who knows?
Welcome to the rebranding hell.

[richwalters]

Those clear tube verticals are 6550B's...don't get confused with the NOS A version and basic 6550 which are near subs for KT88's.

If I am right nobody makes the 6550A or plain versions anymore. (a pity)

The 6550B and C are rated max 470V in UL so don't push them higher. I have loads of B version and despite it's boring looks is a well behaved tube. The C version has exotic wire coatings and better mechanics thrown in.
However, there isn't any evidence they last longer unless other users can testify.

I don't believe the B version ever qualified for JAN status and those boxes could be a hoax. Perhaps someone can correct me ?

richj

[alexg]

Upon further research and searching for Svetlana 6550 materials, I think this is a Svetlana 6550B-3.

At this site: http://www.harpamps.com/micKtubes/Svetlana-6550s.html
the tube that is referred to as "cleartop" is the Svetlana 6550B-3 and whose description matched the tube pictured on post #1.

The seller finally told me that he thinks it was sold as "Ruby 6550", Ruby has been re-branding Svetlana a few years back and now, rebranding mostly Chinese 6550/KT88 (mostly Shuguang), based on my readings.

Thanks everybody for sharing your information, now I am more certain of the origin of the tube.

[fdegrove]

Hi,

You can be 100% sure about those tubes.
Basically these were 6L6GCs on super steroids and one of the early efforts of the Svetlana folks at making their version of the RCA 6550.
Early batches were rather flaky with lots of unstable ones.
At that time, around late 1991-92 something like that there wasn't much of a choice unless you wanted to pay through the nose.

The best ever remain the NOS Tungsol which had an uncanny abaility to pervey to flow of the music. Hard to describe but you'll know it when you hear it I suppose.

BTW, just for info, Tronal is just a brandname of a Belgian wholesaler. Most of the Tronal branded tubes are sourced for the ex USSR countries and Eastern Europe. IOW, nothing to write home about.

Cheers,

[alexg]

I decided to purchase the 6550B-3 together with the 6550C.

My amp is not very hard on tubes as the manufacturer told me, anyway for the price, it is quite irresistible (he wants around US$110 for the eight tubes, slightly used, though, I will have it tested before purchasing it).

If I do not want it, I can easily resell it here in the Philippines where people pay US$200 for a quad Svetlana 6550C or JJ KT88.

Am eyeing a quad of slightly used Genelec KT88 from an acquaintance, and I am saving up for it. I have tested on my amp, and I am quite astounded with the sound.

Thanks for the info, Frank.

[s2kov]

goodluck alex!

[richwalters]

Frank mentions super steroid 6L6's.....If the 6550 series was a clone attempt on a up'ed 6L6.....Where does the akin 5881 historically fit into the picture....???..as this tube has a bit higher rating than a 6L6.

richj

[fdegrove]

Hi Rich,

As far as the USSR manufactured tubes go, first you had the native 6L6, the 5881 was derived from a Russian ruggedized version of the 6L6 resulting in the flat socket 5881.

The 6550 came later when the Chinese version turned out to be a major piece of junk. Can't recall exactly when that was though.

Ciao,