Replacing 6550s with KT 88s

Let me start by saying that the SED =C= are very good tubes and were most likely the ones used by c-j to voice your LP 70S.

c-j is currently using the New Sensor Tung-Sol KT120 in their current production amps and the LP 70S should be able to accommodate the higher heater rating. The owners at c-j think very highly of this tube as do most c-j users.

The New Sensor Gold Lion KT88 also comes from the Saratov, Russia factory and is, in my opinion, an excellent choice. I do not find it to be "tubey" sounding although there is an area in the upper midrange/lower treble where I think that 6550-based tubes excel and you may prefer them for that reason.

I do an audio web log for fun and you might want to read some further thoughts on this subject here:

http://jda1951.xanga.com/764150002/new-sensor-gold-lion-kt88/

I've listened to all of these tubes in both a c-j Premier 11A and Premier 140.

Hope this helps a little and good luck in your pursuit.

Hi Joe
Many thanks. It's advice and insights like yours that makes Agon such a
great resource and community. For a tube novice like me this is invaluable.
Enjoyed reading your blog and will post my impressions post acquisition of
a new set of pre and power amp tubes which should arrive ,hopefully within
the next 10 days.
Cheers
Pradeep

If you replace all of the tubes at once(pre and power); you won't know what tubes made what change, or to what degree. Just a thought: replace the preamp tubes first, and listen for a while. Put the old pre tubes back in, swap out the power amp tubes and listen for a while. If you are replacing the phase splitter and driver tubes: make that a separate/distinct step as well.

Rodman
Many thanks. You are absolutely correct.I intend to do this slowly and in phases to try and guage the effect of each tube. Am interested in your comments/experience of the NOS 6550s vis a vis the Winged C current production
Cheers
Pradeep

I had been purchasing NOS Sylvania 6550's, from Upscale, until his supply ran out. Went to the =C= and felt I was missing nothing(at that point). Those had over four years on them when replaced with the NOS GE 6550A octet. Thus- I can't offer a valid, direct comparison. It's my impression, however, that the GE's are a more dynamic, open & cleaner tube, than either the Sylvania or =C=(at the same bias setting). Once you have listened to your rig with the new compliment of tubes for a time: Try some NOS Siemens E188CC's or 7308's(direct replacement, identical in every parameter to the 6DJ8/6922), in your phase splitter and driver slots.