KT 88 vs 6550 Any True Differences

R

robertnjax

Active Member
I'm using the MC275 Mk V amp with the stock Mac branded KT 88's. This amp can use either 6550 or KT 88 output tubes. My question is: Is there a real functional / audible difference between these tubes or is it the same tube with different numbers? One of my friends says that the KT 88 is a more durable tube. I looked through the AK threads, but could not find any comparisons between these two tube types:scratch2:

Thanks, Robert
 
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not an easy question!
there are good and bad 6550 and kt 88 .it also depends very much to match the sonics of the tubeamp, i compare them in differnt amps some like a usa ge 6550 better some kt 88

this could be a long thread
 
Just my own experience,
My MC60's sound best with original Tung Sol 6550's. Svetlana KT88's I have aren't bad either in it either.
My MC275 MkIV does not care so much about the Tung Sol 6550's but likes KT88's and the GE6550A's. I had a couple quads of the 6550A's laying around anyway so I am going to use them up with it.


Carl
 
Its like the "Yin" and the "Yang"

KT88 = Yang = strong, powerful
6550 = Yin = soft, lucid, smooth

depending on what U like, to each his own.

My ex MC275 SS (Mk III)'s came with the 4, 6550's in a McIntosh walnut box.
My current MC2000 has has 8, KT88's in a oblong card box.

Personally, I like the KT88 "sound" better!

Also different brands (of even same type) exhibit different sonic characteristics.

Know this is not much info, but do hope it helps - from a user point of view.

Cheers.
 
I have a quad of the Sylvannia 6550's somewhere but I forgot where and what they are like. :(
I will find them, just not when I am looking for them.


Carl
 
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The tube books tell me that the 6550 is the US version of the European KT88, refers me to the same set of curves and specs.
 
The 6550 was first. To jump start sales at GEC-MOV (General Electric Corp- Marconi Oscram Valve) after GE purchased them, they repackaged the 6550 and called it the KT88. The KT-88 was 'up-rated' for higher voltage and of course had a larger envelope which is always good for tube life.
The small 6550 Sylvania tubes make a lot of power. Maybe the most of any in the 6550/KT88 family.

Thanks,
Ron-C
 
It depends on the amp . . . . . .

I think junkaudio makes an important point
.it also depends very much to match the sonics of the tubeamp
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eg: Audio Research has been using SED 6550's in their amps for quite awhile now, and yet their amplifiers have a reputation for sounding rather "dry" as tube amps go (not "dry" as referring to SS amps.) I'm quite pleased with the KT88's in my 275MkIV (though not the OEM ones) They have air and sparkle, and the amp sounds way better in my (exact same) system than my ARC 140W triode monoblocks with (8 per side!) 6550's.

I suppose if I were to try 6550's in my MC275, I'd use Tungsols simply because my understanding is that Tungsol introduced them as an American response to the European KT88. Maybe that's not the best reason :scratch2: but that's where I'd start :yes:
 
after long listening i did a mix on my audioresearch classic 60
four svetlana 6550 and four valve art kt88 sound just right for me
bias is ok
 

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I ran Tung-Sol 6550's in my MA-2275 and liked them much more than the Gold Lion KT-88's but preferred the KT88's in my vintage MC-275. The Gold Lions are known for their power output which can certainly increase the output to more than 90 wpc. The KT88's sounded more muddied in MY system

I agree with Serge on the Svetlana Winged C KT88's from Kevin at Upscale Audio (Doug's Tubes, a AK site sponsor, did not carry them although he is a super guy and have dealt with him on other tubes). A very good tube that sounds super with both the MA-2275 and the MC-275 and is much cheaper than either the Tung-Sol 6550's and the extremely pricey Gold Lions. A true value at under $175.00 shipped for a QUAD of triple matched tubes. May not have the full depth and power (although they may) of the old stock tubes, but for the $, you can't go wrong.

As with everything, each ear is different as well as settings so YMMV but both 6550's and KT88's are excellent and have long life and sound great. The only person who can really decide which may be better for your system is you however so we all hope whatever you decide, you will enjoy.
 
I settled on GE 6550A's for the MC275 IV. I tried SED 6550's & they also sounded good - better than any of the KT-88's I tried. Better balanced mids/highs in my system.
 
Thanks for the advice. I'm sure that the current set of factory Mac branded tubes will last for a long time. I always want to have a set of spares around!
Robert
 
Spare set

Anyone who prefers the OEM MC275 IV/V tubes should really keep a backup set on hand. Please send me a PM, I'm sure we can work something out :yes:
 
Holy smokes, I just looked at that auction site to see what my still NIB GE Jan 6550A's were going for. I guess I should have bought the other ones at the time too. :sigh:


Carl
 
Yes, but . . . . .

ron-c said:
The McParts department is standing by whenever you need replacement tubes.Thanks,Ron-C
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that replacement tube may or may not match the others you received with your amp. Better to have a near new, already proven reliable, matched set, for the price of a couple KT88's from McParts :yes: -- I guess that gold lettering must cost quite a bit :no:
 
CarlV said:
Holy smokes, I just looked at that auction site to see what my still NIB GE Jan 6550A's were going for. I guess I should have bought the other ones at the time too. :sigh:


Carl
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Carl, how much are they going for ? I have 18 of them NIB. I suppose they are appreciating faster than my house ?


Rick
 
We can't talk pricing in this forum. I just signed into ebay and looked at completed auctions.


Carl
 
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