[Freo-1]

I'm looking for inputs regarding the current crop of new production 6550/KT-88. I have tried the following:

Genelex Gold Lion Re-Issue: Great sonics, poor reliability. I've had trouble keeping pairs working longer than 100 hours or so. They either go cherry or create a blue light show.

Svelenta 6550C (95 production). Recessed sound stage, lack of midrange warmth. Seems reliable. The 6550C issue is confusing, in the the plate construction on the 95 vintage looks like the New Sensor 6550C, while the Winged "C" look different (rectangular holes in the plate).

Svelenta KT-88 (98 production). Similar to 6550C, but a bit more bass.

JJ KT88 (99 production). More midrange, but has a dull overall sonic signature.


None of these sound as good (to me) as the GE 6550A, but as we all know, they are getting very scarce.

So, what's been everyone's experience, and recommendations?

 

[zybar]

I like the Genelex Gold Lion Re-Issues and have zero problems with two quads I purchased from Jim McShane.

Both quads have well over a few hundred hours on them at this point.

George

[mfsoa]

I have a quad of the reissues, also from Jim.

Zero issues over hundreds of hours.

-Mike

[Freo-1]

Glad to hear some of you have not had problems with the Gold Lion Re-Issues. I sometimes think that I may have gotten two bad sets. I also have gotten feedback from amp repair folks reporting similar problems with the Re-Issues.  I'm not going to use them until I get feedback that whatever issues they have have been addressed.

FWIW, GE 6550A's have never given me a lick of trouble, and have been long lasting. I was wondering if any other folks have had good luck with a given 6550/KT88 tube. The fact that the manufactures are all using the Winged "C" tells me something.

[K.C.]

The RAM branded KT88s sound great in my RM9. I feel they're very balanced and have never heard a better sounding KT88.

http://www.tubeaudiostore.com/kt88sovtek.html

[pbrstreetgang]

Believe it or not out of

Sovtek 6550
Svetlana 6550 Winged C
Shugang KT88

I like the top to bottom coherence, 3D imaging and overall presentation of the Sovtek. Go figure

[K.C.]

Believe it or not out of

Sovtek 6550
Svetlana 6550 Winged C
Shugang KT88

I like the top to bottom coherence, 3D imaging and overall presentation of the Sovtek. Go figure

The RAM KT88s are Sovteks, though very select Sovteks. Listening to them now and they're wonderful.

[diamondsouled]

I'm using the New Sensor KT88 Gold Lion reissues for the past 6 months with no  problems so far.

These were purchased from tubedepot and were from a new batch, they were back ordered and weren't shipped until they'd received the new order.

 This is McShane's experience with them: 

 Second, some news on the Genalex KT-88 front...

I had an email from a gentleman this morning who was concerned about the quality of the Genalex reissues. He purchased 8 from me a year ago, and four had sudden failures. He told me he wasn't going to use them other quad since he didn't trust them. BTW, he didn't ask for anything in return, he just wanted to keep me informed. No axe to grind, so to speak...

This is the single largest group of failed Genalex I've seen. And I've been reporting that I think Genalex quality is quite good, so I went back to do some research. This is what I found...

Up to this point I've sold (or have ready for sale) about 750 Genalex KT-88. The total number of tubes returned was 11 - and adding the four he wrote about makes it a total of 15 tubes. Percentage wise, that is a failure rate of 2%.

The last 250 tubes have had 3 failures, so the failure rate of recent stock is 1.2%. One of those 3 was an open heater which showed up during test/match of course. The other 2 were field failures of tubes in the customer's hands.

The predominant failure mode has been internal shorts, but exactly what elements are shorting I don't know for sure. I've never had one fail in testing. When they do fail it's early in the tube's life it seems - but not so early that 24+ hours of run-in finds it.

When researching the emailer's situation, I found that the tubes he got were from a batch that had the highest failure rate of any. You may recall that I posted how Mike Matthews wanted the tubes returned to him personally (which I did) so he could personally carry the news to the Saratov people. Unfortunately I can't pin down the EXACT failure rate from that batch, but it may have been as high as 8% or so. The higher rate was what prompted my contacting Mike, and his fast reaction to it.

Since that time the failure rate has dropped steadily, and as I mentioned above, it now stands at just over 1% (be aware this is the tubes I sold/tested, I have no knowledge of any other seller's experience). I think it's possible the one batch wasn't as good as the others; but after my careful review I'm quite confident in the tube's quality.

In the email, he mentioned he had a friend that worked in an audio store, and that hid friend said they were having "problems" too. So rather than speculate I went back to my records to see what had transpired. I'm glad I did.

The bottom line - I'd GLADLY use that tube in my own gear - in a heartbeat!! I think it's a terrific tube. Oh, and I did offer to replace his out of warranty quad at a special price as a thank you for his help in feeding back the information.

------

Seems that there are a few people experiencing problems with the Gold Lion KT88 reissues. At least with the batch sold a year ago.

When and where were your's purchased if you don't mind me asking and what amps are you running them in?

Cheers

Larry

[twitch54]

Genalex Gold Lion KT-88's in a pair of Rogue M-150's, less than thirty hours. No issues as of now. Customer of Jim McShane as well.

[Freo-1]

Be glad to:

I purchased them last summer/fall from a gentlemen who specializes in my reference amplifier (Harmon Kardon Citation II).  It should be noted that the amp has been completely modified/restored to look like a NOS 1960 model.  The front end was changed out from 12BY7 to 5687 triode, and let me tell you, the transformation is nothing of incredible. The power supply was re-done with over ten times the original capacitance, a more stable bias setup with dale mil-spec pots, hexfreds, and a very cool Simpson current meter (0-100ma).

I generally run GE 6550A tubes, and have had only one go flaky (from age). They have given me no problems whatsoever. But, being OC audio geeks, we are always looking for improved sound, and the fact that the GE's are getting scarce  was also a motivator. So, after reading all the hype about the Genalex Re-Issues, I gave them a whirl.  I was so impressed with the sound, I immediately got a spare set.  I thought they were great (for awhile, then, Wham! Tube Trouble abounded). I run the tubes biased a 50ma, which is well within the tubes range (the original design was at 100ma!!)

I went back to the GE's, and of course, they were no problem. I also began to appreciate how good the GE's sounded after listening to the Gold Lions. I obtained replacements for the drama tubes, and went back to them. Less than 100 hours later, a light show I would not wish on anyone occurred. 

A new set of bias resistors, and going back to GE's put the amp back in order.


The dealer is a good guy, he also sold me a set of JAN GE 6550A, along with a set of 7044 when the tube rolling bug bites. The 7044 is a great sounding tube (a little more neutral than the Tung Sol 5687). I happen to like the extra warmth with the Tung Sol. The 7119 is even warmer (almost too warm with the GE6550A, but very nice with the Genalex).

So, I hope that the Gold Lions serve everyone well, and if reliability stays up over time, I will eventually try them again (I'll make sure I have extra bias resistors on hand, though, just in case)

Lastly, was wondering what experience anyone has had withe original GEC KT-88. I keep reading they last a LONG time, and the sound is simply the best.

[Freo-1]

Believe it or not out of

Sovtek 6550
Svetlana 6550 Winged C
Shugang KT88

I like the top to bottom coherence, 3D imaging and overall presentation of the Sovtek. Go figure

The RAM KT88s are Sovteks, though very select Sovteks. Listening to them now and they're wonderful.

A lot of that may have to do with Roger's stringent test methods. He knows what he is doing. Perhaps contacting his store would be in order.

[mfsoa]

Genelex Gold Lion Re-Issue: Great sonics, poor reliability. I've had trouble keeping pairs working longer than 100 hours or so. They either go cherry or create a blue light show.

Update - I had one of the Genelex reissue KT88s do the blue light show on me, after about a year of moderate use.

Now I'm in the "Do I replace 1, all, or switch brands" pickle.

Considering just calling VAC and having them provide what they think is best.

-Mike