6550

[Rafale]

6550 SED winged C are difficult to find in decent prices in Europe, I shall wish knowledge so certain of you tried quartets of JJ, EH,Sovtek or other brands on their amplis CJ in particular on the LP series
thanks in advance friends

[turntable]

Yes, Philippe the winged C's are hard to find.

I am using Tung Sol reissues in the prem 8a's and they are excellent. perhaps not quite as dynamic as the Svets, but very good

[repman]

+1 on the Tung Sols I use them in a CJ 11-A they do not seem to have the bass of the winged C's but I actually preferred the sound of them in my system overall. My winged C's are sitting in the tube case resting.

I am now trying a set of Gold Lion KT -88's and liking them maybe another tube you might try.

[evilfij]

Tungsols.

I actually prefer them to the Gold Lion Kt88 at least in so far as I cannot tell much difference and they are about 1/2 the price.

[Rafale]

thanks for your input
any of you have tried 6550 JJ ?

[Rafale]

6550C Svetlana -C- Logo - Powertubes: Pentodes (http://www.tubeampdoctor.com/en/shop_other_brands_OEM_Tubes_Powertubes_Pentodes/6550C_Svetlana_C_Logo_570)

just delivered of 2 quartet of 6550 SED winged from this dealer, fair price and fast shipping

[Rafale]

I am surprised noticing that at my supplier the Tungsol KT120 is less expensive than SED 6550 C logo

[Coppy]

Here is a reply from a friend at CJD to my inquiry about the KT120s:


Ed passed this along to me. We have been very much taken with the sound of the new KT120 tubes. Sound quality is even better than our earlier favorite, the "winged C" tubes from Russia. The KT120s are a plug-in replacement for the 6550s on all of our amplifiers. They have higher voltage and dissipation ratings, so should prove extremely reliable (though it is a bit early to be sure of that). The power output of a given amplifier will not change when the KT120s are substituted for 6550s. They are capable of being run for more power, but only if the amplifier is designed for that (higher plate voltages and a different turns ratio on the output transformer). But this means that they are being run very conservatively when simply replacing 6550s.

Aside from catastrophic failures (arcing or short-circuits), I find that output tubes often are good for about twice as many hours as the more critical input and driver tubes (as long as not operating with disastrously low impedance loads - no worries with your Wilson speakers), so should be good for around 3000 hours. When the time comes to replace the outputs, I would definitely switch to the KT120s.

Bob:yes:

[Rafale]

Thanks for sharing Bob, very useful....

[Coppy]

Glad to provide the info. Think I'll order a set for the LP140s and deal with the tube cage issue when they get here.

Hope you're feeling better.

Bob

[turntable]

Thanks Coppy

Ed still does not elaborate on a general basis on what the sound qualities is like compared to the winged C 6550's.

If it is a fatter bass like has been reported, that would not be a good match to my system

cheers

[Coppy]

Glad to provide the info. Think I'll order a set for the LP140s and deal with the tube cage issue when they get here.

Hope you're feeling better.

Bob

Well the Kt120s are in the LP140s but only have about 10 hours on them. At first I noticed better (not fatter) base and faster transients but less depth to the sound. Base more like my P350. As they are burning in the debt has returned and the mids are wonderful. After a few more hours I'll do some critical listening of some familiar reference music and report back. Despite the lack of tube cages, I'm actually pleased with the appearance as they seem to better fill the tube cavities of the amps and pleasantly match the space; there's no longer the former hollow appearance without the tube cages. No report on the WAF as yet.

[Rafale]

Excellent, Bob, could you please send us a photo of the LP140M with the KT120?

[aldinohiend]

Every 6 months I control the bias on my CJ Premier 140. This morning, to my surprise, many LED for adjusting the bias does not light up. I'm worried and I replaced the eight valves with new ones. The eight LEDs are all lit and I could adjust the bias.
It means that the valves where the LED is not lit, have become exhausted?

[Joe Appierto]

Every 6 months I control the bias on my CJ Premier 140. This morning, to my surprise, many LED for adjusting the bias does not light up. I'm worried and I replaced the eight valves with new ones. The eight LEDs are all lit and I could adjust the bias.
It means that the valves where the LED is not lit, have become exhausted?

Hi,

Yes, it most likely means the tubes have worn to the point where they are outside the bias range of the Premier 140.

Out of curiosity, what type of tubes were you using and do you know how long/how many hours they had on them?

Thanks,

[aldinohiend]

Hi,

Yes, it most likely means the tubes have worn to the point where they are outside the bias range of the Premier 140.

Out of curiosity, what type of tubes were you using and do you know how long/how many hours they had on them?

Thanks,

It was Jan 6550 GE Green Logo and had about 2500/3000 hours.
I take this opportunity to make a couple of questions. If on my final CJ Premier 140 I mount the KT88 risk anything? And yet, someone has mounted on the final CJ the new KT120 and with what results sonic?

[Joe Appierto]

It was Jan 6550 GE Green Logo and had about 2500/3000 hours.
I take this opportunity to make a couple of questions. If on my final CJ Premier 140 I mount the KT88 risk anything? And yet, someone has mounted on the final CJ the new KT120 and with what results sonic?

With that amount of hours, you were most likely at their useful end of life and that explains why some would no longer bias properly.

From personal experience, I can say that I never had any problems using KT88 types in either the 11A or the 140.

There are some threads here on the Conrad-Johnson forum that discuss the KT120 pretty extensively, so you might want to take a look at them. Generally, it's been a very popular tube. Also, c-j has been outfitting their most recent amps with this tube as stock equipment. For whatever reasons, it's never been one of my favorites but that's just me and I don't represent the majority view here in this regard.

[Coppy]

With that amount of hours, you were most likely at their useful end of life and that explains why some would no longer bias properly.

From personal experience, I can say that I never had any problems using KT88 types in either the 11A or the 140.

There are some threads here on the Conrad-Johnson forum that discuss the KT120 pretty extensively, so you might want to take a look at them. Generally, it's been a very popular tube. Also, c-j has been outfitting their most recent amps with this tube as stock equipment. For whatever reasons, it's never been one of my favorites but that's just me and I don't represent the majority view here in this regard.

But, Lew Johnson, the J of c-j thinks the KT120 tube sounds much better and calls it the new "super tube". See his comments and quotes on other threads here.

[Joe Appierto]

But, Lew Johnson, the J of c-j thinks the KT120 tube sounds much better and calls it the new "super tube". See his comments and quotes on other threads here.

I know and respect his opinion highly. Other members here are uniformly positive about it as well. I guess it's just me.

I had them in the 11A just a few days ago and they do have a great deal going for them. I then switched them out for the New Sensor Tung-Sol 6550's and I just like the NS T-S 6550's more. I also like the NS Gold Lion KT88s better.

I'm not normally a contrarian but in this case, I guess I am.

[chessman]

I know and respect his opinion highly. Other members here are uniformly positive about it as well. I guess it's just me.

I had them in the 11A just a few days ago and they do have a great deal going for them. I then switched them out for the New Sensor Tung-Sol 6550's and I just like the NS T-S 6550's more. I also like the NS Gold Lion KT88s better.

I'm not normally a contrarian but in this case, I guess I am.

Joe, bravo for going with your own ears. :thumbsup:

[aldinohiend]

I've always wondered why Conrad Johnson does not recommend mounting the KT88 on its finals while gives assent to the KT120.
What experiences have you, and in particular about the Premier 140?
That is the Premier 140, if I mount the KT88, what risk?

[turntable]

https://picasaweb.google.com/107162311956054071422/Hifi#5775345868431252530

https://picasaweb.google.com/107162311956054071422/Hifi#5775345868431252530

Interesting the difference in size between the kt120 and 6550. Both samples tung sol

[Joe Appierto]

Shane,

Looking at the sheer size of the KT120, you could almost believe it is the equivalent of two 6L6's packed into one bottle. At least that's what I've read one poster say about them.
__________________________________________________ _________________

Aldinohiend,

Please don't take this as an endorsement because if something should happen to your Premier 140 as a result, it'll only add to my Catholic guilt...but I've never had any problems using KT88 tubes in my Premier 140.

Regards to you both,

[turntable]

Yes Joe

They certainty are big buggers. Tung Sol 6550's now back in the prem 8a's. Really like these tubes :yes:

Just bought a little Google nexus 7 tablet. Cheap and pretty dam good - prefer it to my wife's iPad for web surfing. However can't seem to get it to post pics, hence the link only. PC so much easier for pics, cut and paste.

Cheers

[Myles B. Astor]

I've always wondered why Conrad Johnson does not recommend mounting the KT88 on its finals while gives assent to the KT120.
What experiences have you, and in particular about the Premier 140?
That is the Premier 140, if I mount the KT88, what risk?

A number of factors enter into any manufacturers decision in choosing a particular brand of tube to use or recommend.

1. Sound
2. Availability
3. Reliability
4. Price

Perhaps Lew and Bill had some issues with #3? Remember cj is very conservative. Lew and Bill remember the early days where tube equipment was horribly unreliable and drove away many potential customers. They really believe that the more reliable that tube gear is, the more it will sell.

And look VTL amps where they have a special circuit that tells you when and which tube is going and makes it a breeze to replace.