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KT88/6550 suggestions

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Posted on March 26, 2017 at 15:16:21
Thermionic27609
Audiophile

Posts: 411
Joined: March 29, 2009
 I'm installing the tubes4hifi 12AU7 driver boards in a pair of Dynaco MkIIIs for someone, and we need to choose the output tubes.

He describes his listening tastes as 80% Classical and 20% Dave Brubeck style jazz. Speakers are Sansui SP-3500. And he is older, which may have some bearing on perception of higher frequencies. I doubt the amps will be pushed hard. Preamp is a Marantz 7T that was reportedly completely serviced a few years ago, with some new electrolytics installed.

The budget limits us to current production types.

Suggestions for system synergy?

 

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RE: KT88/6550 suggestions, posted on March 26, 2017 at 15:29:38
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 The "best" current production KT88 is New Sensor's "reissue" Gold Lion.

If money is very tight, buy ElectroHarmonix (EH) KT88s. Other than being a tad bass shy, the EH variant is fine and it is an excellent value.

Discuss the need with AA sponsor Jim McShane.


Eli D.

 

RE: KT88/6550 suggestions, posted on March 26, 2017 at 16:07:26
Michael Samra
Dealer

Posts: 36118
Location: saginaw michigan
Joined: January 30, 2005
 What Eli said.
"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

 

RE: KT88/6550 suggestions, posted on March 26, 2017 at 20:16:58
Thermionic27609
Audiophile

Posts: 411
Joined: March 29, 2009
 Thanks for the suggestions. Just to ask the question, how does the EH KT90 stack up? I ask because I did another pair of MkIII >10 years ago and used EI KT90s, no longer available. Those were wonderful.

 

RE: KT88/6550 suggestions, posted on March 27, 2017 at 00:56:31
Eli Duttman
Audiophile

Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 The EH KT90 started out as a POS. It has gotten better, but it remains behind both good EI KT90s (the last specimens made were trash) and the "reissue" GL.

Unless there is clear, convincing, evidence that EI made KT90s predate the end of production junk, pass them by. Mere claims and promises will not do. Don't get ripped off.


Eli D.

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 01:24:09
Mechans
Audiophile

Posts: 1804
Location: East Coast
Joined: May 23, 2004
 I couldn't agree stronger about the Gold Lion KT-88 from New Sensor. The problem is that they are relatively expensive but certainly not near as much as NOS. I think they are worth the money. I didn't care for the EH.

 

RE: KT88/6550 suggestions, posted on March 27, 2017 at 02:37:51
tubular.well
Dealer

Posts: 223
Joined: March 4, 2013
 JJ-KT88 from Eurotubes.com is a winner, and with good warranty for those that are nervous. ( not affiliated with eurotubes)

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 08:21:17
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 I'm using them right now and I love them.

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 08:22:11
samzx12
Audiophile

Posts: 378
Location: Kentucky
Joined: November 6, 2002
 What Mechans said :)

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 09:34:53
mcgjohn@yahoo.com
Industry Professional

Posts: 501
Location: Midwest
Joined: February 5, 2008
 The GLs are nice. But for a warmer sound, the Mullard KT88s will offer a warmer presentation that the GLs.

Also the Tungsol 6550s are a nice tube. Have a set of those in a pair of MC60s.

best

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 09:49:12
samzx12
Audiophile

Posts: 378
Location: Kentucky
Joined: November 6, 2002
 You are the 1st person I have heard give any feedback concerning the Mullard KT88. Have you compared the GL and Mullards or heard both?

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 10:46:40
Nunki
Audiophile

Posts: 644
Joined: November 27, 2010
 forget that GLs, Mullards or EH stuff! Penta KT88 SC beats each of those!


 

Agree...., posted on March 27, 2017 at 11:11:38
Mossback
Audiophile

Posts: 1871
Location: Washington, the State
Joined: November 17, 2001
 I agree with you Eli, those reissue GL from Jim are not only the best value they are reliable as all get out.
Psvane Tll are slightly more musical IMO but more costly.

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 12:39:09
samzx12
Audiophile

Posts: 378
Location: Kentucky
Joined: November 6, 2002
 Thanks for the heads up Nunki. In what way do the Pentas beat the GL and Mullards in your opinion?

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 14:01:45
Nunki
Audiophile

Posts: 644
Joined: November 27, 2010
 well, in MY gear (rogue audio ATLAS MAGNUM) the pentas sound crispy, fast and lifelike. great even for classic music.

previously i tested KT88 brands like GL(reissue), JJs, Sovtek, Treasure Z, Svetlana winged C, Psvane KT88 T-Mk II, Ei KT90, TS KT120 etc.

the Tresure Z is a great KT88 too but finally i sticked with the pentas. they do nothing wrong.

N.


 

+1 on the PentaLabs KT88SC, posted on March 27, 2017 at 14:27:20
Mendel
Audiophile

Posts: 1207
Location: GTA
Joined: January 17, 2009
 The PentaLabs run is over, now sold by the tubestore.com as the Prefered Series KT88. Even come with a 6 month warranty. Dougs tubes also has them under the "Ruby" name I believe.
This is the "best" currently manufactured KT88 on the market.

 

RE: KT88/6550 suggestions +1 more GL, posted on March 27, 2017 at 15:39:42
mcgjohn@yahoo.com
Industry Professional

Posts: 501
Location: Midwest
Joined: February 5, 2008
 have a quartet of each. The Mullard 88's have a fuller, much warmer sounding midrange than the GLs or the Tungsols. Not too far off the original Mullards from the UK.

Have the Mullard KT88s in a PL dialog amp with Jensen copper foil caps, and MILLs WW for the plate and cathode resistors.

If your re-worked amp is a tad on the warm side, the Mullards might be too much of a good thing. All depends on the other components that are used.

The Tungsol 6550s sound great (well balanced) in a Mac 275 or CJ MV75.

As one other poster noted, there are also some premium KT88s out there, but have not tried em.



 

RE: +1 on the PentaLabs KT88SC, posted on March 27, 2017 at 16:13:23
Thermionic27609
Audiophile

Posts: 411
Joined: March 29, 2009
 Ruby isn't listing the KT88SC (KT88V-STR) on their site at present, so I wonder if Doug's Tubes is only selling remaining stock purchased from Ruby.

The TubeStore apparently has them as its Preferred Series KT88.

That is something I calculate into tube choices. If, for example, one tube fails in the first few months, do you want to find out that you can't get them anymore?

 

RE: +1 on the PentaLabs KT88SC, posted on March 27, 2017 at 23:49:15
Nunki
Audiophile

Posts: 644
Joined: November 27, 2010
 the Rubys have holes in the anode plate. the penta SC have solid plates and definitely no holes!

 

RE: KT88/6550 suggestions +1 more GL, posted on March 28, 2017 at 04:26:22
samzx12
Audiophile

Posts: 378
Location: Kentucky
Joined: November 6, 2002
 Thanks John appreciate it. I was always interested in the Mullards but could never find much feedback.

 

RE: KT88/6550 suggestions +1 more GL, posted on March 28, 2017 at 10:02:26
mcgjohn@yahoo.com
Industry Professional

Posts: 501
Location: Midwest
Joined: February 5, 2008
 NP.

Just don't forget (as am sure you are aware), the coupling caps also influence the tonal qualities of a given amp.

If you are using Russian K40s, the Mullard 88's might be a bit too much, so would opt for the GLs or the Tungsols. On the other hand if you are using a V-cap for couplers, then the Mullard 88's may be a nice selection.

 

RE: KT88/6550 suggestions +1 more GL, posted on March 28, 2017 at 11:06:02
samzx12
Audiophile

Posts: 378
Location: Kentucky
Joined: November 6, 2002
 I do remember John you mentioning the cap upgrade path. I have not gone down that path with my Primaluna Dialogue Premium. Right now I am using the GL KT88 and experimenting with 12AU7. I have some NEC 12AU7 Mullards(highly recommended) on the way so once I get these evaluated I'll have a good sense of the direction I am headed. So far, I like the GL however, it is amazing how much influence they have on the overall sound and tone.

 

RE: +1 on the PentaLabs KT88SC, posted on April 3, 2017 at 18:37:08
sherod
Audiophile

Posts: 4842
Location: Texas
Joined: August 3, 2003
 Doug's Tubes stocks two versions of the Ruby tube, the KT88-STR, which is the Shuguang Kt88-98, three holes and the KT88V-STR which have the solid plates and is his current substitute for the Penta KT88SC.

 

By the way..., posted on April 3, 2017 at 18:43:25
sherod
Audiophile

Posts: 4842
Location: Texas
Joined: August 3, 2003
 The Ruby KT88V-STR solid plate is supposedly the same tube, the Preferred Series, that Tubestore sells.

 

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