Replacing 6550s with KT 88s

Rodman9999
I am curious about what changes you found using the NOS GE 6550s as compared to the Winged C 6550s. It may be possible to get a quad NOS from Singapore.Incidentally what power amp are you using?
Many thanks
Pradeep

I can be a little more "frequency specific" in as much as I also use CJ amps, (Premier 12's) but I bi-amp my Apogee Duetta Signatures with them on the woofer panels...these handle low bass up to lower midrange and when I swapped out the SED Winged C 6550's with EH KT-88's the KT-88's did just what I had hoped: punchier, more extended and articulate bass control including a lower midrange that also stayed smooth and rich...I can't speak for the rest of the frequency range though so take my experience for what it's worth for you. Good luck

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.