Daddy Dee Posted September 13, 2005 Share Posted September 13, 2005 I continue to enjoy these Mark III's rebuilt by autospec (on Audiogon). Interesting guy in Idaho and he does good work. He sent them to me with Svetlana 6550's as stock and they sound very good. Do you have a recommendation for an alternate power tube that you have really liked in Mark III's? Anything that you'd recommend to stay away from? Appreciate any advisement here. Quote Link to comment Share on other sites More sharing options...
lwhaples Posted September 13, 2005 Share Posted September 13, 2005 DD, I'm not much help.But I do have an intrest also,as my MK'3s are at Craig's. I'm sure I'll want to do some rolling after I've had them awhile. Larry Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted September 13, 2005 Author Share Posted September 13, 2005 Larry, So what tubes were in your Mark III's upon arrival? I'm hoping Craig will chime in on this thread. I imagine that he has listened to ALOT of tubes in the Mark III's. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 13, 2005 Share Posted September 13, 2005 Sure I'll chime in. I've listened to just about every current production tube available from the KT88, KT90 and KT100 family. A few that I haven't would be the JJ KT88 and the current Svetlana/SED tubes since the mix up between there name and what not I have just steered clear of them all together. The current production 6550's I have not messed with at all. As far as NOS I have listened to pretty much everything and there all to rich for my pocket book I just don't see the value in spending huge amounts of money on tubes that wear out like output tubes do. Small signal tubes are the place to spend the money on NOS IMHO. My personal favorites would be Penta Labs Shuguang KT88SC Valve Art KT88 or KT100 (I can't tell a difference between the two visually or sonics) All 3 of these tubes are made in the same factory that was licenced to reproduce the GEC KT88 way back when. I have customers that love the JJ Telsa KT88 and the EH KT90. I believe thay have what I call "China Syndrome" myself (there from China they can't be good) [] Heck I have it when it comes to most consumer goods. Another thing about all these tube preferences that has to be understood is the old saying "One mans garbage is anothers gold" Its really all a personal preference. Craig Quote Link to comment Share on other sites More sharing options...
3dzapper Posted September 13, 2005 Share Posted September 13, 2005 Dee, The Mark III had a justifiable reputation as a tube killer. The high plate voltage and, especially, the very high turn on voltage spike shortened the life of the then popularly avaliable GEs, Tung Sols and RCAs considerably. Due to this, I would be loathe to spend $250 or more on a quad of NOS KT-88s or 6550s and instead use less expensive new production reproductions, as Craig suggests. Maybe the "new" Tung Sols? Rick Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 13, 2005 Share Posted September 13, 2005 Rick, Not sure where you got the idea the voltage spike would hurt the tubes? A KT88/6550 can easily handle the voltage present at turn on in a Mark III. The thing the voltage spike kills is the original filter can in a Mark III it was rated at 525V and the Mark III hits 575V on start up. I bet GaryMD that has my old MArk III's has a good number hours on his Mark III's also. I have a work around to completely elliminate the voltage spike. I have a set of Penta Labs KT88's here that have 5000+ hours on them in a set of VRD's that actually present a harder load on the output tubes and the buggers still test like the day they were new. The KT88 are capabe of producing 100 watts of power per pair the Mark III's or VRD are not even coming close to touching there limits. Craig Quote Link to comment Share on other sites More sharing options...
garymd Posted September 13, 2005 Share Posted September 13, 2005 I've never replaced the ValveArt KT-88s that came with my MkIIIs. They sound great to me and the price was right since they came with the amps.[] I doubt I'll ever spend big bucks on output tubes for them although I may try some KT-90s just for kicks. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted September 13, 2005 Share Posted September 13, 2005 I can vouch that the JJ KT-88s are really fine sounding in a pair of VRDs. Are they worth replacing the stock set of Valve Arts? Well, they sound slightly better to me, but probably not worth the full price difference. But I did it before I knew.[] Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted September 13, 2005 Author Share Posted September 13, 2005 Thanks all for the feedback. Craig, what you mention about the startup spike.... Would the Mark III be helped in this regard with some kind of soft start circuit. I've seen some guy who has these on Ebay. Looking over his website, he has kind of a basic soft start and an "audiophile grade" soft start, which somehow takes itself off line after 45 seconds and the amp gets straight current. What I'm wondering, if it would be helpful. Would it diminish the sound in any way? Or just an audiophile nervosa thing to go off line after it starts up and settles down? Any help appreciated. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 13, 2005 Share Posted September 13, 2005 Dee, I can't vouch for the one you mention because I have never used it. I use an In Rush current limiter myself on Mark III's it does the job just fine. But in your case this maybe a great option. The VRD has no problems with the spike since I use a power supply setup that can handle the voltage with ease. Craig Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted September 13, 2005 Author Share Posted September 13, 2005 Thanks, Craig. Quote Link to comment Share on other sites More sharing options...
louis Posted September 13, 2005 Share Posted September 13, 2005 i have 4 of the new mullard 6550 got by mistake have about 50 hour on them the reproduction shipped for 90.00 if want louis Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted September 14, 2005 Author Share Posted September 14, 2005 Louis, Thanks for the offer. I didn't realize that there was a new Mullard 6550. Seems like I have seen some reissued Mullard EL34s. Rick, Yeh, I've been looking at the reissue of Tung Sol's 6550. They sure do look good. One fellow told me that nobody has yet been able to come up with the exact composition of the plates of the vintage Tung Sol 6550s. Perhaps a rumor among the audiophile crowd. With the Mark III's apparent rep for wearing out power tubes, I am also reluctant to pay the market price for vintage on this amp. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted September 14, 2005 Share Posted September 14, 2005 Dee, Let me say this one more time. A properly working and biased Mark III will not wear out power tubes prematurely. It's the power supplies that were short lived. Craig Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted September 15, 2005 Author Share Posted September 15, 2005 Craig. o.k. got it. That does make sense. Thanks. Dee Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted September 15, 2005 Author Share Posted September 15, 2005 One thought to add here. In addition to my thanks for the responses to this thread.... .... it is encouraging to hear pretty much consensus that current manufacture tubes sound very good in the Mark III's. Don't know how much that's the case with other power amps. Seems that the preamp is the little guy who benefits most from NOS tubes. Quote Link to comment Share on other sites More sharing options...
lwhaples Posted September 15, 2005 Share Posted September 15, 2005 I should add Thanks also, I always seem to learn a good deal from others questions. Larry Quote Link to comment Share on other sites More sharing options...
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