Tung-Sol, 6550, old vs new

I'm could not find a thread with a " A-B comparison, so I of these two 6550's so did it myself. I have come to the conclusion that advice is good but, advice is sometimes biased towars that person liking. ( mine will be as well ) I have read many times the original Tung-Sol 6550 is the best 6550 - bar none - So I finally went out on a limb and purchased some original Tung-Sol, and also some current issue Tung-Sol. I don't have an expensive tube tester so I cannot test for plate voltage, but I can test for emissions, leaks, and shorts. My original issue Tung-Sol passed all 3 tests so I took a chance and popped them in! And my response was.....

Wow! Very open sounding, a lot of air without being bright. Excellent imaging, and very holographic, with excellent bass. I have listened to the following 6550's: SED winged C, Penta Lab's 6550, GE 6550A, and Tung-Sol reissue 6550. So I have not yet heard all there is to offer so my opinion is biased. Of course if there is anyone out there that would like me to try out their favorite 6550 in my comparisons, feel free to send me a quad :) For what it's worth I have also listened to some of the KT88 family: Sovtek, Telsa, and SED Winged C.

Back to the AB comparison. The Old Tung-Sol beat the reissue in every category except perhaps in sweetness ( IMHO ) the reissue had a sweeter midrange. Actually I found the reissue to be warmer overall. I once thought the SED Winged C was the best current 6550. However after listening to the Tung-Sol reissue I have changed my tune. The reissue is not as good as the old Tung-Sol, no way! But it is quite good for a current issues tube!

But that original Tung-Sol 6550? Best I have ever heard!


I've used the reissue (originals are out of my price league) Tung-Sol 6550s, and I thought they were a well balanced tube, maybe just a little lacking at the bottom end. Not exceptional, but not a tube I could say was bad. Then I bought a quad of Genelex reissue Gold Lion KT88s and heard a clear difference in every regard. Clearer, bolder and warmer. Sounds just popped up and out. No comparison.
Nice review, could you tell me what vintage tung-sol do you have. I have or had gray plate with 3 hole and halo getter, solid gray plate with halo getter and the very hard to find black plate with single top getter and they all have the classic TS house sound but at the same time they have their own slight flavor. I too have tried the current production TS 6550's and were bested by any of the 3 genuine tung-sols I have tried on my system except by a small margin the current production TS had slightly more punch in the bass. I had the opposite result as you had, in my experience the current production sounded dry compared to any of the more refined and richer sounding genuine TS in my system. Just my experience.
I'm using 3 hole, 3 halo, gray plate. I think in general how the tube sounds varies based on the amp and associated equipment. I remember that the Sovtek KT88's sounded great in a different amp I had, but now they are blah compared to the Tung-Sol reissue. I have read good things about the Genlax reissue but am a bit tubed out right now. If I get the energy I might purchase some for a A/B test. But then again what I heer would be a bit biased. I was also curious about the EH 6550 and or KT88's but for their price, can they really compare?

I forgot to mention I have also listened to the Chinese KT88 that seems to work well in the VAC amps. For me it had a sucked out midrange but nice highs.

keep tweaking!