Sound of SED Winged C KT88 vs. SED Winged C 6550's


Curious as to what if any sonic differences I could expect in comparing the SED KT88's vs. their SED 6550 counterparts. I've researched the forums quite a bit over the last month or so and even asked the question to Kevin Deals gatekeeper @ Upscale Audio... his response was that there was little to no sonic differences between the two.

My amp is a McIntosh MC275 MKV, currently using the stock McIntosh KT88's, which I've been told by Audiogon's Nsgarch, are SED KT88's.
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I switched from EH6550 to GL Reissued KT88 several years ago and the GL is SUPERIOR in every way. Surprisely GL is warmer but also much higher resolution.

My amps require 4MQ so NOS is out of the question. Looking for a tube with the sound of GL Reissued KT88 but higher resolution. Willing to give up a touch of body and bloom ... I DON'T want a SS sound. I'm satisfy with GL but like to experiment ... a bonus with tubes.

I try not dealing with Upscale any longer. ~A years ago I emailed Upscale, Goodwin High End and Audiowave on a EquiTech 2Q. Only Alan @Audiowave replied and ended up purchasing 2 new units from him. Thank GOD for the internet ... have found many great dealers.
Knghifi, I doubt that you will find what you are seeking with the re-issue Tong-sols. Compared to the SED 6550's their bass is bigger, yet tight, mid-range a tad warm, and highs natural. The SED's are more linear and in the wrong amp they can sound clinical (just as the Tong-sols in the wrong amp can sound a bit too warm). I've never heard the GL reissues but from what I've read I would assume they are similar to the SED 6550's with a bit more warmth and extended highs, but that is a WAG.

FWIW, when I'm seeking greater clarity I more often than not go to the small tubes and find success.

Hope that helps a bit.
This is from "the tubestore" Gold Lion KT-88
"In 1957 Marconi-Osram Valve Co. (Genalex) introduced the "King of Power Tubes", the legendary Gold Lion KT88. This tube became the heart and soul of such classics as the Dynaco Mark III, McIntosh MC275, and Marshall Major. Unfortunately, Genalex ceased tube production in the early 1980s and the Genalex Gold Lion KT88 has become very expensive and hard to find."

"After extensive research and engineering, New Sensor Corp. has reissued the famed Genalex Gold Lion KT88. This tube has been recreated down to the finest detail with gold plated grid wire, carbonized screen grids, and a tri-alloy clad plate structure for exceptional performance and sound quality."

I used these in my Quicksilver V-4's and loved them. Worth checking out!!
I think sounds best with KT-88's rather than 6550's and the best new production KT-88 is the Gold Lion re-issue.
Newbee, thanks for the comparison.

It's tough to roll power tubes since the amp requires 4MQs. I'm satisfied with the sound of the amp so probably stick with GL reissued KT88 when it's time for a new set. Already rolled all the small tubes ... was just curious on SED and Tung-Sol 6550.