Tube amps and speaker ohms

My new Leben CS-600 can use 6L6GC, EL34, KT66, KT77, and KT88 among others. I find I enjoy the 6L6GC (RCA Black plates) more than SED Winged "C" EL34 because the 6L6 produce a larger and more open sound, IMO.

I was curious to try KT88, but Trelja's comment about the KT77 caught my attention. What's a good modern production KT77...JJ?

Tvad - FWIW, dealing with like kinds, ie SED's, I found the 6l6GC slightly mellow thru the upper mids/highs compared to the EL34 in both of my Primaluna amps which were primarily designed around the EL34 or the KT88 and to my ears both sound best with that the tube around which it was designed. I've been sort of interested in hearing an amp designed around 6L6's but I haven't found one yet. I tried them in my Baron but they were to hot - I'd have to get it modded (it takes 5881's).

JJ is the only maker of KT77's right now that I'm aware of. On AA several posters have been high on the sound they make, but there is some strong comments on quality control and pin size. FWIW - you probably already knew that.

05-28-07: Newbee
Tvad - FWIW, dealing with like kinds, ie SED's, I found the 6l6GC slightly mellow thru the upper mids/highs compared to the EL34 in both of my Primaluna amps...

I noticed just the opposite in the Leben. Interesting. It might have to do with the brand of tube being compared.

Thanks for the info on the JJ tubes. Quality control is extremely important. It makes the Osram KT77 tubes at $200 ea start to look like a good value if you tend to burn through bad JJ tube after bad JJ tube.

Grant, my KT77 comments are based solely on listening to the JJ variant. I'm not sure how the Osram (didn't know they made KT77) and Mullards would sound.

In my Jadis DA60 and Dennis' (Badboss429) Quicksilver, a bunch of us (including Mechans) compared the JJ E34L blue glass, JJ KT77, vintage 1960s Mullard EL34 XF1 (EL34 Holy Grail), and JJ KT88 blue glass. The KT88 came in last. The rest of the tubes had a variety of opinions. Overall, things seemed to split between the Mullard and JJ E34L, but many of us couldn't get past the powerful, intoxicating lows of the JJ KT77.

From what I heard, the first batch of KT77 had issues with the tube pins. The octet I bought in January/February 20076 had this issue corrected. Didn't have any fail, either, but it's a complaint many have put forth with JJ power tubes in general. I have an octet of E34L Blue Glass, and one day while measuring them about three weeks ago, I found one was as dead as a doornail. That came as kind of a shock.

Hi Divad. I tried to post before, but I cannot see the post so here goes again.

First off, I am a very pro tube guy, but I would advise you very strongly against going tubes with your speakers. Your speakers are not suited for a tube amplifier.

You may get them to “work” by using a big tube amp, but it is never going to be a good match and neither your speakers nor the tube amp will be sounding their best. You’ll be much better off with a solid state amp.

If you really want to try tubes, you need to ditch the B&Ws.

Regards
Paul