Home Tubes Asylum

Questions about tubes and gear that glows. FAQ

Re: Need help on Shuguang KT88-98 or GEKT88?

There're six Shuguang 6550s and KT88s - 3 6550s and 3 KT88s, oh, and the KT100. Make that seven...

KT88
- KT88 - wrap-around metal base
- KT88-98 - holes in plates
- GEKT88 - no holes in the plates

6550
- 6550 - ST-glass; looks like a Tung Sol
- 6550A - plastic base and ST-16/G bottle (I don't recall right now if that's technically the correct envelope type description)
- 6550A-98 - looks similar in profile to GE 6550A

KT100 - square-shouldered bottle

All can be found, new or used. Some are easier to find than others. The KT88-98 and GEKT88 are fairly readily available today. Pentalabs, Ruby Tubes, and Valve Art each sell one or the other types. I have 6550A-98s branded Ruby Tubes. I have a lot of the 6550s, mostly branded generically ("Made in China"), or as Groove Tubes or Mesa Engineering. I just bought a bunch of NOS, generically branded ones for just a few dollars each. I passed on a similar number/price of the plastic base tube. So these tubes are out there and can occasionally be found for very good prices. The KT100 often wears many different kinds of branding, and even type labels. I've seen them labeled as KT88s, KT100s, and even 6550s (Antique Electronic Supply has listed some of these as Peavey branded and typed as 6550s).

I like all of them. All of them have proven as good as, or even better than, any other KT88 or 6550 I've listened to across dozens of different systems. BUT, I have had more trouble with them than any other 6550 or KT88 brand. I've had new quads with dead, shorted tubes, tubes that alleged passed through very strict QC (GT, Mesa, Ruby...). And I've had them just decide to up and die with few hours on them. I've had very few problems with SEDs, EHs, or Sovteks, for example; and likewise US-made 6550s are comparatively much less trouble. But danged if the Chinese tubes don't sound great...

Some folks claim that sonically the plate-holeless GEKT88s are the best sounding. The KT88-98 is typically positioned as the most durable. I think the character of each of the different variants is similar enough that I don't have a strong preference for one over another. In my gear to my ears (again, tried in dozens of different systems) they all are dynamic, extended, detailed, and also tonally characterful and bloomy. I like them all.

- SJ


This post is made possible by the generous support of people like you and our sponsors:
  Kimber Kable  


Follow Ups Full Thread
Follow Ups
  • Re: Need help on Shuguang KT88-98 or GEKT88? - tvr2500m 20:49:27 09/05/06 (0)


You can not post to an archived thread.