KT88's

Hi Steve,

Well one of the advantages of membership of the EU is that we don't pay customs duties when buying stuff from other member countries, so for me in the UK buying the tubes from France is a lot cheaper than from the US.

Because the Prologues have automatically adjusting bias I've also tried the EL34 and the 6L6GC. Very interesting different colours and presentation. The EL 34 is good on voice, but bass light. The 6L6 has a real vintage feel, so if you are into 30s or 40s recordings they may provide a more authentic sound. There's no doubt in my mind though that the KT88s are best – simply cleaner, more accurate and they have this quality that's often described as “muscularâ€Â.

Hi Neil, I've not tried the 6550, but I doubt they would be better than the KT88. But it is just soooo subjective – if you like the sound well it's better for you. One thing though – I think that the small signal valves set the basic character of the amp and you need to get those sorted first. It can become a bit obsessional and you have to remind yourself that it's the music that's important.

I think Shuguang must make valves for several companies to 'badge engineer'. I've not tried the Valve Art version. There seen to be two main types: the KT88-98 which is the basic type and is the one I've tried. And the more expensive GEKT88 which is an exact copy of the original GEC KT88 design. This one is supposed to be very good according to what I've read on some US message boards.

 

Hi Ants, I've not tried the KT90 either. I feel it may be best to steer clear of the more esoteric types like KT90, KT77, 5881 etc. They either seem to have major reliability problems or have distinctive characteristics that some love and others hate. There’s also the issue of just how compatible they are in a given amp. I prefer tubes to be reasonably neutral and therefore accurate, not imposing too much of their own signature.

 

Hi Blue Note (nice label!),
To be honest I was a KT 88 guy but did slot in some Svetlana 6550Cs - I was very impressed. Perhaps not as "punchy" in the mid-bass area but really good.
Neil

 

I'm running KT90 Ei Mrk 3's at the moment. They're more powerful than the KT88 and sound less tubey than most. Only one out of 16 isn't working properly, so they're not too bad for reliability.

 

Tim, the word on the streets is that Ei has ceased production. I don't know if someone will buy the business or what. So I might wait a bit before investing in their KT90s. Reviews on the EH version aren't so good. Don't know of any others.

HiFi World mag has always been a bit sniffy about the 6550 generally recommending KT88s. So it is interesting that you've had a good esperience with them Neil. They're also very well regarded in the US so I may give them a try at some point.

So many valves so little time…

 

As far as the 6550s go I'd thoroughly recommend the Svetlanas - streets ahead (IMO of course..) of other 6550s It's interesting to read this : www.jacmusic.com/KT88/kt88.htm interesting info from the company I got my "Valve Arts" from.

 

Phew! more types of KT88 than I knew existed. I think a key point is that the valves will sound different in each type of amp – horses for courses. I've seen the Svet winged C KT88 criticised for being rolled-off or muddy sounding. The Prima Luna Prologue Seven monoblocks that I have do seem to be inherently on the bright side of neutral. The warm sweet sounding Svets compliment this resulting in a well balanced presentation. Perhaps in a completely neutral power amp they may seem to lack sparkle?

 

It turns out I have Svet winged C KT88s and Golden Dragon small valves on my 7s (still using dealer's pair while awaiting delivery.) I wouldn't call them bright at present. For quite I while I thought they were perfectly balanced, but I see what you mean, possibly, BN, re perhaps being slightly less than sparkly at the top end. I felt that a little, in comaprison with my other system. I will remember your comment when I get delivery of the stock amps, which are PL-branded Shuguang, IIRC, which are supposed to be rather good in their own right.