AudioNervosa
Systemic Development => Amplification and Preamplification => Tubes => Topic started by: Emil on January 08, 2018, 08:15:49 AM
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Once upon a time many amplifier companies used them but not anymore it seems.
Supply? Sonics?
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The Svetlana ("SED" in the US) 6550C "Winged C" was the standard power tube for VTL, Audio Research, Cary Audio, and many others for many years. SED Svetlana stopped making tubes a few years ago, and the supply of 6550 dried up in about a year as people horded them for these popular amplifiers. The discontinuation of this tube was the cause for AR to switch to KT120 tubes as standard and redesign their entire power amp lineup.
Svetlana's old website (https://www.wingedc.com/) lists Antique Electronic Supply (Tubes and More) (https://www.tubesandmore.com/products/6550c-winged-c)as their direct sales agent in US, and they still have 6550C for sale, but it is not made in the original St Petersburg Svetlana tube factory, and the internal construction is different, according to customer comment on the 6550C detail page. (https://www.tubesandmore.com/products/6550c-winged-c)
American company Tung-Sol invented the original 6550 tube in the 50s.
New Sensor's (Russian made) Tung-Sol 6550 and Gold Lion KT-88 are excellent replacements for the SED 6550C. Shuguang Black Treasure KT88 is also excellent. I think Gold Lion KT88 is much better than SED 6550.
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Once upon a time many amplifier companies used them but not anymore it seems.
Supply? Sonics?
It is a shame. I still have 6 of Winged C 6550s from late 90s/early 2000s. I also have 7 Winged C KT88s from same dates (both St. Petersburg). The two do sound different, but both are easily usable and sound fantastic; just have to tweak the amp to whichever one wishes to use. Right now I am saving them for special times.
I am currently using the SED KT88s, much less expensive, but would one day like to test the new Tung Sol 6550s in my monoblocks. The monos can use either 6550, KT88 tube, and with the high/low tonal switches in the power supply I designed in, all I have to do is flip one, two, or both tonal switches and install other tubes.
I suppose manufacturers are considering the new KT120s, or KT150s? Any input?
Cheers
steve
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They have the same pinouts, but they draw more heater current, and output more power, which would overload some OPTs that are barely big enough for 6550. KT120 are also heavier tube than 6550, so you can't run them sideways in amps with vertical PCBs like old ARs, even though those have enough PS and tranny to handle them. The later AR amps with horizontal PCB like Ref110 can run KT120s. The new AR Ref75 is able to make 75W with single pair of KT120, said to be a real honey of an amp.
Jim McShane recommends the new TungSol 6550s for amps that used SED 6550. He says his customers are happy with them.
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Carl Marchisotto, owner and designer at NOLA keeps telling me that I just have to get Ref 75 is hands down the best amp to run my Boxers with.
Unfortunately, there are about 8,995 reasons why I can't run out and order one right away. :roll:
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For me when I had my Jolida 502P amp I had the best sound with a quad of NOS matched GE 6550 tubes that were cryo treated in the amp. The problem for me is the cost. I paid a lot of money for those tubes then one of them blew up. I had to then sell the trio at a loss. I was heartrbroken and didn't want to buy a NOS quad of 6550s again. Then after that I got onto the Tung Sol KT 150s in the Jolida.
My conspiracy theory is that people wanting more wattage numbers just kept pushing the KT88s KT120s and the KT150s. The good ol 6550s got left in the dust. Plus the KT88s look so cool.I remember having a quad of blue Glass JJ KT88s and they looked so big and cool.
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It is also a matter of cost and complexity in the amp design. It is certainly easier and cheaper to design a circuit with a pair of KT-120s as opposed to a quad of 6550s.
And it is also a marketing thing because there is also the prestige of owning and amp with the biggest, baddest tubes on the block that can help sell an amp.
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Using [ 20 ] 6550 tubes in the Audio Research DR 250 Mk2 Servo amp. That is why it is sitting there un-used. Besides they were my Maggie Amp. Maggies 3A's long gone.
charles
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It is the money and then not the money. That AR is best suited for inefficient speakers like Maggies, no more Maggies. One more reason is that the Arion HS500 class "D" hybrid [6H30 input] is much better than AR 250.
charles
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It is the money and then not the money. That AR is best suited for inefficient speakers like Maggies, no more Maggies. One more reason is that the Arion HS500 class "D" hybrid [6H30 input] is much better than AR 250.
charles
The 6H30 is THE BEST I have ever used in a preamp. That is what I retubed my insanely modified Cary SLP50B with and there was no comparison to any 6922 variant I had tried.
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It is the money and then not the money. That AR is best suited for inefficient speakers like Maggies, no more Maggies. One more reason is that the Arion HS500 class "D" hybrid [6H30 input] is much better than AR 250.
charles
The 6H30 is THE BEST I have ever used in a preamp. That is what I retubed my insanely modified Cary SLP50B with and there was no comparison to any 6922 variant I had tried.
Agree 100% especially if they are those Russian babies.
charles
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It is the money and then not the money. That AR is best suited for inefficient speakers like Maggies, no more Maggies. One more reason is that the Arion HS500 class "D" hybrid [6H30 input] is much better than AR 250.
charles
The 6H30 is THE BEST I have ever used in a preamp. That is what I retubed my insanely modified Cary SLP50B with and there was no comparison to any 6922 variant I had tried.
Did you have to do any mods t get the Cary to run with 6H30s or are they direct plug in compatible with 6922s?
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Not to my Knowledge. Should be a direct replacement. Not cheap at $300/pr NOS Reflectors.
charles
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Not to my Knowledge. Should be a direct replacement. Not cheap at $300/pr NOS Reflectors.
charles
you definitely cannot use 6h30's in a circuit designed w/6922's. there's much info on line about folks asking that very question.
doug s.
I stand corrected I guess. My preamp had zero issues. [ Gary Dodd] Best to verify first.
charles
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Thanks Doug. I kind of figured that part to the modifications Dave did to his Cary were to allow the substitution of the 6H30, but I thought I would ask.
Sounds like it would largely be a function of how much extra umph you have in your power supply. I sent off an email to ARC tech support earlier to today, posing the question to them. I'll ne interested to hear what they have to say, but after reading your last post I don't hold out much hope.
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Not really interested in doing any mods to the SP-9 right now. I just thought that if they were plug in compatible it might be fun to grab a pair of 6H30s and swap them in for the 6dj8s and see how it sounded. Current production 6H30s would only run me about $60 for a pair and if I didn't like them I could always swap them back.
Not looking to get into a big project,just a little one afternoon nervosa fix.
But if I can't swap them without modding the amp it will involve much more effort than I was looking to put into this.
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Oh wow, I thought that the preamp was modded to so that you could used those special tubes. But if he could mod some 6922s for me that might be interesting. $85 is not cheap, but I only need two tubes and I have plenty of spares on the self, so the grand total would not be that much.
Something to think about...... :-k