Best KT88 for MC275V

[vintage_tube]

So, why even mention 13K, like it's some ultra-rare, never before reached stratospheric rating ??????? They may as well have said 26,000 or 5,000.

 

[ruffoc]

Touche, Neil.

Another fallacy -- as you know, each manufacturer of tube testers has different specs for tubes. Hickok, 539C, for instance has a 63% rating for KT88's of 6400. Weston has another reject point (RP) specification; Heathkit TT-1A has a RP of 1340. So, published 5 figure gm rating mean nothing to me & hold no importance.

Here are the measurements I received on the last two sets of KT-88 ordered from audio karma sponsor The Parts Connection. Presumably the test equipment is the same.

SED winged C KT 88’s ranged from 5400-5500 Gm Ip of 48
Gold Lion Reissues ranged from 7500-8300 Gm and lp 687-70

Not sure what this meads or if it proves anything but I did hear an immediate sound improvement with the Gold Lion KT88’s in my MA2275. I can’t comment on my mc2102 as the only tubes I’ve tried are the GL reissues. I bought the unit from a reputable second hand dealer. I was unable to confirm the use of the tubes that came with it so it seemed prudent to replace them

 

[Chaney]

...

 

[nsgarch]

So, why even mention 13K, like it's some ultra-rare, never before reached stratospheric rating ??????? They may as well have said 26,000 or 5,000.

Well no, I think they just wanted to go the NOS Gold Lions one better -- marketing is what EAT is all about after all :yes: I've never tested new EAT's, maybe Chaney has tested his.

 

[nsgarch]

Here are the measurements I received on the last two sets of KT-88 ordered from audio karma sponsor The Parts Connection. Presumably the test equipment is the same.
SED winged C KT 88’s ranged from 5400-5500 Gm Ip of 48
Gold Lion Reissues ranged from 7500-8300 Gm and lp 68-70

Those figures seem consistent with others' experience with those tubes. Test equipment can vary, and some models, like the Military TV/ series, use completely different scales, which need to be converted, but micromhos (transconductance) is a ratio, so for testers in reasonably good spec, Gm values shouldn't vary that much from one to another.

 

[vintage_tube]

Well, yes it's a ratio -- however, IMO you're using 2008 logic on a particular piece of test gear built by many different manufacturers 40-50+ years ago. Back then, prior to RETMA (circa 1953 -- Radio Electronics Television Manufacturers Association), there were no mutually agreed upon tube testing standards and those manufacturers performed development & testing the way they THOUGHT it should be without regard to any mutually agreed upon standards from competitors -- thus the disparity in "bogie values" of tubes in each manufacturers tube specs. Back then, for manufacturers to agree to a single standard took years.

 

[Dr.K]

I'm just a novice with tube gear, only having my MC 275 for about a year, but this thread intrigued me so much I ordered new Mullard 12AX7s, 12AT7s and the reissued Gold Lions from Russia! In my excitement after receiving the new tubes, I broke one of my GE power tubes while I was pulling it out. So, I cleaned up all the broken glass, wiped up the blood, put all the new tubes in... turned on my MC 275, so excited to be wowed...and... I'm not really hearing much difference. Maybe I even liked the sound of the stock tubes a little better, it sounded a little cleaner. I can't exactly remember, and I can't go back because I broke one.

I hear I need to let new tubes burn in a while before I can really tell. How long is the burn in and do they really improve that much after they are burned in? I'm not giving up on this tube rolling thing, but if anyone has some insight on what to expect or what else I need to do, that would be great.

 

[C220MC275]

Me too !

I really like the reissue Gold Lion KT88s I got from Jim McShane at Christmas time....a great present from my wife and they sound marvelous!:thmbsp:

Hi Big Mac,

The same for me. They are a really nice upgrade to the stock tubes. I could not imagine such a difference. Just bought Telefunken used 12AX7 on ebay after all te comments I read on AK. If the difference is supposed to be more than changing the power tubes, so I think I will fall from my chair ( I was already very happy with my amp with the stock tubes...)
Got my Gold Lion from tubedepot at 100 $ a pair.

I wish I could have a wife buying me tubes.... How lucky you are.

Jerome

 

[C220MC275]

Yes !

I'm just a novice with tube gear, only having my MC 275 for about a year, but this thread intrigued me so much I ordered new Mullard 12AX7s, 12AT7s and the reissued Gold Lions from Russia! In my excitement after receiving the new tubes, I broke one of my GE power tubes while I was pulling it out. So, I cleaned up all the broken glass, wiped up the blood, put all the new tubes in... turned on my MC 275, so excited to be wowed...and... I'm not really hearing much difference. Maybe I even liked the sound of the stock tubes a little better, it sounded a little cleaner. I can't exactly remember, and I can't go back because I broke one.

I hear I need to let new tubes burn in a while before I can really tell. How long is the burn in and do they really improve that much after they are burned in? I'm not giving up on this tube rolling thing, but if anyone has some insight on what to expect or what else I need to do, that would be great.

Hi Dr K,

Yes, Gold Lions really improve with time.
I felt the same : first hours were really disappointing : the stock tubes were better. But with time, the difference became really remarkable. Don't worry, you should be amazed.
I don't know for the entry tubes, cause I did not receive the 12AX7 yet....

Best Wishes

Jerome

 

[vintage_tube]

Like all tubes, give the reissues time -- comments above regarding new reissues are common & will improve within the first 2-3 hours or so -- getting better after more burn in time.

If you are going to tube roll -- you need to find someone locally who will at least test the tubes you buy off auction sites -- before you stick them in our expensive gear. All the hoop-la tauting a tube on an auction site is hit or miss and may or may not be the real deal (this does NOT necessarilly apply to legitimate tube sellers, IMO).

 

[javajam12]

Gold Lion

I too am a recent owner of a MC275 IV and it came with the requisite russian
McIntosh KT-88's and chinese small tubes. I thought the sound was very good
using these tubes. Upon reading thread upon thread about the Gold Lion tubes
I purchased a quad. After installing, I detected a slight difference in detail.
After a few days, I'm not interested in taking them out now! Much better in all
regards to the stock tubes. I also replaced the 12AT7's with Mulllard CV4004
tubes and the 12AX7's with the reissue Mullards (new sensor) and this made
an even bigger difference in mid and high end. I highly recommend getting the
Gold Lion reissues. They are a steal at the price point they are selling.
Of course, adding my C220 preamp this week hasn't hurt either! What a great sounding system. Cheers.

 

[Daytripper]

Who makes the McIntosh 12ax7a brand tubes in the c2300? And what would be a good nos and new production replacement tube?



Robert

 

[slee104611]

I replaced my 12ax7a with the Groove tubes on my 275s. Also replaced the 12AT7 with NOS Mullards and the KT88s with the Penta Solid plate KT88s. Love the sound - especially with the Pentas. I am curious to try the Gold Lions though

 

[Dr.K]

Mullards and Gold Lions

After 3 days of listening, I am starting to really like what I'm hearing. Don't know if it is the Mullard 12AX7s and 12AT7s or the Gold Lions, but there is definitely an improvement with time. Now I wish I would have not changed all the tubes at once.

 

[vintage_tube]

Dr.K -- probably a combination -- glad to read the optimistic view you wrote this time (verses the "bloody" ordeal post).

Daytripper -- are you speaking about pre in/outs on the C2300 -- well you can go Telefunken (which I'm not especially fond of), RCA or Siemens. I'm begining to prefer Siemens. For phono, same brands with inclusion of Mazda chrome plates.

 

[jloveys]

Well, I am running a matched quad KT 88 E.A.T. Diamond tubes on my MC 275 MKIV since a month and it is like upgrading to a 10000 $ amp. Before I had Philips, Gold Lions, G.E.C's and those E.A.T blown them all away.
Now my MC 275 is the best amp I ever heard. Gives bass and dynamics to my Quads ESL 57 that's hard to believe...

 

[midlife]

Yep I got the fever after taking possession of a 275ce. I'm using Tele (12at7) in the "T" slots, RCA7025s in the "X" slots and am now ready to do powertubes. Thought the Penta kt88sc might be a good choice, but now I hearing GL reissues are top flight. I'm a confused tube newb:sigh:

 

[midlife]

Yep I got the fever after taking possession of a 275ce. I'm using Tele (12at7) in the "T" slots, RCA7025s in the "X" slots and am now ready to do powertubes. Thought the Penta kt88sc might be a good choice, but now I hearing GL reissues are top flight. I'm a confused tube newb:sigh:

As a gross generalization, I believe the Chinese are up and coming in sales and production values and I don't see the same for Russia, my 2 cents

 

[ron-c]

Any of the current production KT88s will work well if you have a good set. Obviously there were issues in the last years with a few tube manufacturers where one of the materials they used had contamination issues. That seems to be behind us now.

This does not mean there is not value in having support from the seller you chose to buy tubes from. There will always be a failure rate even if small. Current MC275 is not hard on tubes.

Thanks,
Ron-C

 

[midlife]

For a 275ce already using tele 12at7s, and rca 7025s, which would you choose for power tubes (want an upgrade from 6550 sovteks), $208 GL reissues quad, or Penta KT88sc @ $180 quads ?:yes:??