Click title to read one, or click date to read all below it.
09-14-05
My offer to send down a dozen of the kt-88eh's on loan still ... Zaikesman
09-14-05
Come on nate, i'm ready ! maybe we can get pat malone, stev ... Albertporter
09-14-05
Alex, i sincerely appreciate your offer. you, nate and bea ... Albertporter
09-15-05
Although bea and i are talking about different kt-88's (mine ... Zaikesman
09-15-05
Alex, if you do that test i would be eager to hear your conc ... Albertporter
09-15-05
No doubt. it took me the better part of a year to become ev ... Zaikesman
09-15-05
Alex, now you have my curiosity aroused, how much did you fi ... Albertporter
09-17-05
I have it on good authority that the denver audiofest will s ... Albertporter
09-17-05
Albert, i know it's unfair to ask you to do so but when you ... Lugnut
09-17-05: Zaikesman
From what I've read, it seems among people who switched, somewhat of a majority prefered KT-88's, but I can think of a few reasons why that may be a skewed sampling, so I don't read too much into it. The topic is addressed in some AA threads, and if you search the Net you'll find more.
I suspect your 750's will have the qualities you list in your fourth paragraph no matter which output tubes you use. IMO these are mainly a function of high power and large power reserves, and with two pairs of 750's, I'd imagine there could not even be a question there. But having said that, I will stipulate that in absolute terms and with everything else being equal, in my system the 6550C's do sound a little more 'powerful' than the KT88EH's (partly because they actually are about 1.5dB louder, partly because of their tonal balance).
For pristine treble, there seems to be consensus that the KT88EH, at least, is superior to the 6550C, as I have found. I don't see that consensus with the SED version. There seems to be some feeling that KT88's generally image better than the 6550C, which I have also found, though someone who prefers the musicians to sound as if they're in the room rather than in the original performance space might disagree.
To your last paragraph, I'd say the bass will definitely be different, but whether it will be compromised will be a matter of opinion. Again, in my system, it's not the bass per se that gives me any pause about the KT88EH, because I think it's actually more natural-sounding than with the 6550C, but the overall balance, and neither tube is perfect to me in that regard. On the other hand, I've not heard an EL34-based amp with highs as clean, detailed, and extended as I get with the MB-185's fitted with the KT88EH's, but I probably don't have enough experience for that to prove much (for one thing, I think I've only heard EL34's wired for ultralinear operation). I usually think of EL34's as sounding pleasingly consonant, but not as wideband, clean, and transparent in the highs as KT88's apparently can be. In any case I have little doubt that you'd find the KT88EH's better in the highs than the 6550C's, which may be the more pertinent question.
I do find it interesting that the word on the Web overall in no way seems to place the KT88EH in some kind of lower echelon despite its roughly 1/3-cheaper price compared with the SED and JJ versions, either in sound or reliability. I also saw a couple of positive reports about the Chinese Shuguang KT88-98 - though maybe with a sonic preference different than mine - and from my most recent experience in the area (comparing Russian and Chinese 6SN7's), I wouln't rule out hearing any of the late-model Chinese non-miniature tubes either.
FWIW, here's the ranking arrived at by Vacuum Tube Valley in their home audio listening test for 6550/KT88 types:
1. Genalex KT88 Gold Lion 1969 - 4.87
2. Tung-Sol 6550 1963 Solid Grey Plate - 4.77
3. JJ KT88 2002 - 4.63
4. Ei KT90 1999 - 4.52
5. EH KT88 Reflektor 2002 - 4.16
6. Sveltana 6550 2001 - 4.13
7. Svetlana SVKT88 2002 - 4.09
8. Svetlana SV6550C Reflektor 2002 - 3.98
9. Philips Sylvania 1970s - 3.98
10. Chinese 6550 Valve Art 2002 - 3.89
11. GE 6550A 1970s - 3.78
I pulled this off a thread somewhere from a guy who presumably copied it from VTV (I don't think they make this stuff available online) but not the whole article, so I have no idea about the conditions or ancillaries involved in the test, or how the numerical scores were derived. In any case, though the KT88EH fared well, they obviously really liked the JJ in their application (note that the KT90 is not a drop-in replacement for VTL amps that use 6550C's), and the test seems to have been done before the Svet/SED split, or the introduction of the new Tung-Sol 6550 (not an exact copy) or Shuguang KT88-98. It's kind of noteworthy that they didn't prefer the newer Svet 6550C to the previous version, which isn't the received wisdom I've seen elsewhere.
Upshot Which Lets Me Maintain Deniability: If you're thrilled with the sound using 6550C's, why gamble on such an expensive change before your current tubes wear out? Rolling output tubes could accomplish nothing more than to show you how they're all flawed... :-)
Zaikesman (Reviews | Threads | Answers | This Thread)
09-17-05
Pat, i spoke to koetsu on friday to be sure my check arrive ... Albertporter
09-18-05
For the record, i have cleaned many many lps. with regard t ... Eldartford
09-19-05
What does that have to do with audiofest, eldartford? Albertporter
09-19-05
Zaikes, i appreciate the info on tube ratings you discovere ... Albertporter
09-19-05
Zaikesman: i found your detailed post on tubes very interes ... Gallant_diva
09-19-05
Albertporter...it has to do with lugnut's unrelated comments ... Eldartford
09-19-05
Understood, thank you for replying. Albertporter
09-19-05
(hmmm...thread seems to be developing something of a 'surfac ... Zaikesman
09-21-05
Zaikman: you ask good questions. i have answers to some and ... Gallant_diva
09-21-05
I've done some audiogon forum searches and there is a lot on ... Zaikesman
09-22-05
like i stated before, wish it was easier to do a test. onc ... Albertporter
09-22-05
Well, here's hoping your system 'blows away' listeners more ... Zaikesman
09-23-05
Good advice zaikes, fortunately i live in dallas, where mos ... Albertporter
09-23-05
It might now sound perfect yet, but it sure looks good! Nrchy
09-23-05
Nate, is that louis's system or mine that might not sound pe ... Albertporter
09-24-05
Sorry ap i was responding to your comments on louis's system ... Nrchy
09-25-05
Well, this was a wonderful night. in spite of the worst tha ... Albertporter
09-24-05
I was over at albert's place tuesday and heard some of the f ... Mobileholmes
09-25-05
Phillip (holmes that moves around :^). thank you one millio ... Albertporter
09-25-05
Even though i'm a little behind the curve with albert's syst ... Lugnut
09-25-05
"...the faron young tape pushed the air tights to the w ... Zaikesman
09-25-05
Lug pat, thank you too ! i wish you could hear the new ... Albertporter
09-25-05
Zaikes, regarding "hello walls." yea, i wish i ha ... Albertporter
09-25-05
Albert: this is an area unfamiliar to me. if you know: why ... Zaikesman
09-25-05
Zaikes, there are likely are as many stories about the so ... Albertporter
10-08-05
Update. second pair of vtl ref 750's arrived friday and are ... Albertporter
10-09-05
What a room! that looks like every man's dream!!! Firecracker_77
10-09-05
I went through the "it never rains, but it #$%^& well p ... Nrchy
10-09-05
Maybe barb and i can come too. is this the real deal nate wi ... Lugnut
10-09-05
If you guys are coming again i need to hook up the airtights ... Albertporter
10-10-05
Firecracker_77, sorry i did not respond to you earlier. than ... Albertporter
10-10-05
Hello albert, i am considering the purchase of a technics ... Johnbrown
10-11-05
Kelly, i think the 1520 is an extraordinary machine and hand ... Albertporter
10-11-05
Hello albert, absolutely fabulous setup you have there, esp ... Kuzibri
10-11-05
Kuzibri, my original set of vtl 750's have about 1100 hours ... Albertporter
10-12-05
Albert, thanks for the information and advice according the ... Kuzibri
10-12-05
Kuzibri, i should've been clearer on the subject of small si ... Albertporter
10-12-05
The vtl-branded 6350 is actually a sylvania. nos rca's seem ... Zaikesman
10-15-05
Zaikes, i just bought 8 "hens teeth." four match ... Albertporter
10-16-05
Hmmm...andy was supposed to have me on a 'waiting list' for ... Zaikesman
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