[Steve]

TubeDepot has announced 

As of February 2014, the SED factory is not producing glass vacuum tubes. This is indeed a very sad thing as SED tubes are some of the best tubes out there. Should production recommence, we will let you know.

Another of the best brands, Winged "C" from St. Petersburg not producing glass tubes anymore.

Sad day.

[SteveFord]

This is really not good news.

[doug067]

Yes agreed. I use 2 quads worth of KT 88's in some Dodd monos. Where to go from here should I need tubes again?

[FullRangeMan]

Time to go Triodes.

[Steve]

Time to go Triodes.

Please, let's keep on topic.
(By the way, if you are referring to DHT amps, I have yet to hear a good sounding one in 50 years of auditions, let alone
with good specs.)

One can easily go indirectly heated in triode or ultra-linear mode for better,
more accurate, more natural sound. The winged "C"s were close too, if not
the best sounding around, if properly designs were utilized, which is rare.

But as usual, just as with other parts, improper designs and testing lead to improper conclusions
as to what is superior and what is not.

Winged "C"s should easily have been one of the major brands still out there.

Sad indeed.

[SteveFord]

Of the remaining non-Chinese 6550s out there, which one is the closest in performance to the Winged Cs?
Sooner or later I'll have to retube my VTLs.

[Steve]

Of the remaining non-Chinese 6550s out there, which one is the closest in performance to the Winged Cs?
Sooner or later I'll have to retube my VTLs.

Good question Steve. Each type I have recently been testing requires a different power supply filtering design.
My testing is not exhaustive. However, the plate current is kept constant.

I have found the Tung Sol to be very thin compared to the C 6550. To resolve the best sound from the Tung Sols,
the power supply filtering system will have to be beefed up to fill out the sound.

Older JJ KT-88s seem pretty close, but my "close" may not be as exact as your definition.
I have not tested the JJ 6550.

The Svetlana (New Sensor) seems just a tad thinner than Cs as well, but not too much, so a beefier filtering
system would work out fine.

EH (Electro Harmonix) were much fuller than the winged Cs. Altering the power supply could easily
thin the sound.

I had some Chinese 6550s but cannot find them now.

I have been using the Chinese EL-156, an exceptional
sounding tube, but the screen grid is only rated to 350-400 volts.

Hope this helps Steve.

Steve

[bunky]

I have used the Winged C EL34 6L6GC and 6550 they were all very consistent and reliable.i have a quad of very rare Winged C early manufacture 6C33C-B triodes and I run a pair of them in my 18 wpc SET amplifier and they sound better than any Ulyanov 6C33C-B triodes that I have tried.

[Steve]

Good to hear you Bunky. I have half a dozen of the Winged "C" 6550s. Sure glad I have
them as I see the price is $100/tube now. Yikes.

Cheers

Steve

[SteveFord]

It looks like it's going to come down to JJ and Genalex.

[FullRangeMan]

Please, let's keep on topic.
(By the way, if you are referring to DHT amps, I have yet to hear a good sounding one in 50 years of auditions, let alone
with good specs.)

One can easily go indirectly heated in triode or ultra-linear mode for better,
more accurate, more natural sound. The winged "C"s were close too, if not
the best sounding around, if properly designs were utilized, which is rare.

But as usual, just as with other parts, improper designs and testing lead to improper conclusions
as to what is superior and what is not.

Winged "C"s should easily have been one of the major brands still out there.

Sad indeed.

I was referring to DHTs, EL34 as Triode or 6C33.
I had bad sound memories from Ultralinear and Pentodes.

Though I also had a quad of 6C33 Svetlana bought recently in Moscow I cant would recommend this brand due 3 had low getter at top and just 1 looks OK.
I believe this tubes are some from the last units avaliable in the shop, I suspect they may be problematic rejected ones.
So I fear to use it and are using Ulianov.

[richidoo]

Jim McShane told me 2 years ago when I was looking to retube a VT100 that the availability of SED6550s was inconsistent and the price fluctuated accordingly. Maybe this is why AR switched to New Sensor's TungSol KT120 for their main power tube.

I've had some happy hours of listening to SED6550s in my first tube amp 9 years ago, but I'd sooner buy the KT120s, or Black Treasure KT-88s nowadays. But no JJs.

[Steve]

Jim McShane told me 2 years ago when I was looking to retube a VT100 that the availability of SED6550s was inconsistent and the price fluctuated accordingly. Maybe this is why AR switched to New Sensor's TungSol KT120 for their main power tube.

I've had some happy hours of listening to SED6550s in my first tube amp 9 years ago, but I'd sooner buy the KT120s, or Black Treasure KT-88s nowadays. But no JJs.

 

If they sound different, how do the 120s and BT 88s compare, sonic wise to the winged C 6550s? Is one or both thinner, or fuller sounding
than the Cs?

Thanks Rich.

Has anyone had a chance to compare the 120s to the new 150s? What difference is noted?

ps. I should have mentioned the JJ 88s are older ones (10 years or more) with an alignment problem. One side of the plate starts to glow
cherry at about 37 watts, although rated at 50 watt plate dissipation. Of course I run mine easier than that. Pins are also slightly looser
than other brands. New ones may have the alignment problem corrected as well.

As far as small signal tubes, the JJ E88cc is unbelieveably good sounding for amp or line level preamplifier.

[Steve]

I was referring to DHTs, EL34 as Triode or 6C33.
I had bad sound memories from Ultralinear and Pentodes.

I can understand pentode operation FRM. Pentode offers little damping for the speakers
since its output impedance (Z) is generally quite high, and high distortion figures and higher orders.

One can also use 6550s/KT88s, EL-156s, 6V6, 6F6, EL-84 etc in either UL or triode operation, as triode 
plate curves are triode plate curves. It all depends upon the design as one can alter the distortion characteristics.

Ultralinear can be as good or better than triode, better dynamics. But.... but those who incorporate both UL and Triode
operation in a single amp need to understand that one power supply design does not optimize for both types of operation.

DHTs are too expensive (do have long life though) but all I have heard have compromised sonics, although they can beat out alot of the
average designed amps. 

Cheers.

[DaveC113]

I really like my Winged C EL34s used in triode mode in my SET amp. This is bad news they are going out of production because they were probably the best of the new tubes.

I also have Genelex KT77 and they are better but I just had one go out after 1-1.5 years of regular use. My amp is biased a little hot for el34s if I remember right, about 27W...

[FullRangeMan]

Ultralinear can be as good or better than triode, but.... but those who incorporate both UL and Triode
operation in a single amp need to understand that one power supply design does not optimize for both types of operation.

Good info, thanks for sharing.
My fault is Iam biased againts Pentodes tubes, except EL34 which always had a sweet, warm and musical sound in all times I have heard it.

[Steve]

Good info, thanks for sharing.
My fault is Iam biased againts Pentodes tubes, except EL34 which always had a sweet, warm and musical sound in all times I have
heard it.

Hi FRM,

It is pretty interesting how one can optimize the sound from each manufacturer, even different types from the same manufacturer
(with no change in idle current). As you probably already know, different idle currents can change harmonic structure, thus perception
as well.

I can understand your position as EL34s do have an excellent reputation. The Cs, in general, have always been one of my favorite
brands, especially output tubes. One can get some 6550s and 88s to be ultra transparent, super soundstage, dynamic etc.
6550/88s can be scary good, so I would not give up on those.

I have also heard KT88s with zingy highs compared to the Cs, (EH (the worst) and Svetlana S from New Sensor for example). Might be able to tame those with some work, but why when we had the Cs,,,,,, until now. C 34s are so good, with less work.

Good luck with your continued ventures FRM.

Cheers

[arthurs]

I have 20 cryo'd Winged C 6550's with almost no hours on them...anyone looking for a stash drop me a line.

[Freo-1]

The winged "C" tubes were pretty good some years back, but reliability became suspect over the last few years.  I finally "gave up" on all those 6550/KT88 new tubes, and went old school with 1625 tubes.  They are much higher quality, still readily available, and sound great. 

 



 

[FullRangeMan]

$35 each