Korean 3A3's - Videokarma.org TV - Video

Charlie · #1 08-30-2013, 09:26 PM

I just got a dozen NOS International Servicemaster 3A3C's for 99 cents (8 bucks with shipping). I've used this brand before, but dont really recall where they were made. These, however, were made in Korea. Come to think of it, I don't recall ever seeing any other tubes made in Korea.

Was wondering if anyone here has used Korean made tubes, and if so, do you feel like they performed just as well as tubes from other countries?

I figured for 99 cents, what the heck!

mstaton · #2 08-30-2013, 09:35 PM

Radio Shack used to sell em by the ton

N2IXK · #3 08-30-2013, 09:40 PM

Don't remember ever using Korean tubes, but those International Servicemaster tubes were a REAL crapshoot, especially toward the end of the tube era.

As the major US manufacturers went out of business, they started sourcing tubes wherever they could find them, and rebranding them. Sometimes, they did some really sleazy stuff, like branding common tubes with a different type number for a vaguely similar type, which could be sold for more money. Examples here:

http://www.vacuumtubesinc.com/Vacuum.../Fake6JK6.aspx

http://www.vacuumtubesinc.com/Vacuum...arked5965.aspx

http://www.vacuumtubesinc.com/Vacuum...rked12SJ7.aspx

http://www.vacuumtubesinc.com/Vacuum...sian6L6GC.aspx

http://www.vacuumtubesinc.com/Vacuum...rked6Y6GA.aspx

Charlie · #4 08-31-2013, 03:46 AM

Wow... that's interesting! I used to think that brand was one of the "top shelf" brands to get. Talk about a let-down! Makes me wonder if there is anything "close" to a 3A3 tube. I will make sure to look them over really good. Thanks for that info.

zeno · #5 08-31-2013, 03:43 PM

3A3's are a simple tube so you probably didnt take a
hosing on them.
Brands to avoid to name a few IEC, lindal, radio shack,
newer Raytheon (plain white & red box).
Usually OK are from BIG TV co's. Zenith, RCA, GE, Sylvania
etc. Some brands work a little better in some aps but not a
big issue. 6GH8's can be fussy. In Zeniths the 6HA5 RF amp
came in short & tall versions. The shorties did work better
but the tall ones were easy to get out !
Look at flea markets. There are always tons of tubes around
here anyhow. 75% of the pulls are perfectly good.
Dont trust "new" tubes in boxes. Many are pulls of the same brand.
Assume any tube is used.

73 Zeno

Charlie · #6 08-31-2013, 06:35 PM

Quote:

Originally Posted by zeno

3A3's are a simple tube so you probably didnt take a
hosing on them.

I figured that... it's not like they have a lot of different HV rectifiers to choose from. I guess if I was looking for a nice 6L6, I'd need to be a little more cautious of htis brand.

I've only had one bad experience with a tube that i can recall... a Realistic 25L6 that was just purchased in the store... it lasted a week and then shorted... pretty bad... It sounded as if the chassis was going to explode. Other than that, I've been pretty lucky.

zeno · #7 09-01-2013, 10:22 AM

Quote:

Originally Posted by Charlie

I figured that... it's not like they have a lot of different HV rectifiers to choose from. I guess if I was looking for a nice 6L6, I'd need to be a little more cautious of htis brand.

I've only had one bad experience with a tube that i can recall... a Realistic 25L6 that was just purchased in the store... it lasted a week and then shorted... pretty bad... It sounded as if the chassis was going to explode. Other than that, I've been pretty lucky.

Yes a 6L6 is a good example. Any audio tubes from mid & high line
units are still hot. Most of the NOS & pulls are drying up. Add
to that 6L6's come in different flavors, the audiofile can point out
the differences, my specialty is CRT TV 1965- the end. I do
run a tube Fisher for a HiFi though.........
Bottom Line caveat emptor

73 Zeno

Findm-Keepm · #8 09-03-2013, 05:34 AM

A 33GY7 and a 17DW4A I have are Korean - Goldstar (LG), so they entered the tube market somewhere, perhaps Mexico or Canada. I don't recall anything but US, Japanese, and European tubes in all my years of servicing sets. No markings beyond type, the GS logo, and KOREA.

Cheers,

Charlie · #9 09-03-2013, 10:36 PM

I don't think I've seen a Goldstar branded tube before. That's gotta be kinda rare.

electroking · #10 09-04-2013, 10:04 AM

I have a bunch of Canadian General Electric 6AQ5s made in Korea, among others IIRC.

wb2mep · #11 10-08-2013, 06:37 PM

Another one to watch out for is fake 6LB6's, also made in Korea and branded International Servicemaster. About 2-3 years ago I bought a couple NOS for spares for my living room Zenith.
They were made in Korea had 1982 date codes on them, but were definitely not 6LB6's.
The plates were about 1/2-3/4" shorter, and the cathodes were bigger, about 3/8" wide. They nearly pegged the needle in my tester. They did work in my set, the cathode current was lower than with real 6LB6s, but they arced internally for the first 5-10 minutes after power-up, until it reached operating temperature. I've bee using one in my set for over a year now, and still going strong (and still arcing until up to temp.), but one day it's going to short completely (hopefully the Horiz. fuse will blow and not the flyback).

holmesuser01 · #12 10-09-2013, 08:23 PM

I'd be replacing any tube that arcs at anytime, pronto.

I'm sure you can find 6LB6's.

Zenith26kc20 · #13 10-10-2013, 01:09 PM

Lindal was a big supplier of Korean tubes. Their 6GH8 tubes wouldn't last three months in most RCA tv's. The owner of the shop I worked for at that time would buy them by the hundred.
I do remember the Zenith regulator (6HV5?) from Lindal would turn black in no time.

holmesuser01 · #14 10-10-2013, 03:31 PM

I was given hundreds of LINDAL tubes by a TV shop that I worked for before I opened my own shop. He gave me the tubes, but warned me to not use them because of what they were... bad built tubes with known problems. There was a whole carton of 6GH8's that tested shorted right out of the box on my testers. I didn't use them in anything, and eventually tossed them.

wb2mep · #15 10-11-2013, 05:30 PM

>> I'd be replacing any tube that arcs at anytime, pronto.

I'm sure you can find 6LB6's.

No problem finding them, it's the cost: $25.00 + for NOS.
I'd like to get some use out of them before dumping new $25 tubes in the trash. Just have to keep an eye on the set for the first few minutes after a cold start. There is a fuse in the HOT cathode circuit.
The CB'ers depleted supplies of color TV HOTs in the '70s building their "linear" amplifiers (and to a lesser extent, audiophiles. The amp in my avatar uses 16 European horiz. output tubes per channel) and drove prices thru the roof.