Replacing 6550s with KT 88s


I am currently using Winged C 6550s in my Conrad Johnson LP 70S power amp and am very happy with the performance etc. Some tube sites recommend an upgrade to Genalex Gold Lion KT 88s in place of 6550s. Would love to hear from CJ or ARC owners or others who have experience of this.
Many thanks
Pradeep
Convert?fit=crop&h=128&rotate=exif&w=128sunnyboy1956
If you are after a warmer, tubier presentation; you'll be happy. If you like your sound cleaner/less colored, stick with the Winged 'C' 6550. How old are your 6550's? The comparison(new tubes to older/worn tubes) might not be a fair one.
Rodmann99999
Many thanks for your response.The 6550s are due for replacement. Nearly 3+ years. Not sure how many hrs but I guess it would be close to 3000 hrs. I prefer a cleaner sound to a warm, mushy "tubey" sound.
Cheers
Pradeep
Mr P- Kevin Deal(Upscale Audio) sells both of those tubes. His testing, matching and burn-in procedures are second to none. The last set of Winged 'C's, that I purchased from him, lasted me over four years(at hard labor). I've since gone back to the(NOS) GE 6550A(at over five times the cost). I'm hoping that when that supply runs out, the Winged 'C' will still be in production. BTW: I wouldn't call the Genelex, "mushy." Just somewhat warmer than natural. Some systems are a bit threadbare, and can use the added color. Enjoy your music! (http://www.upscaleaudio.com/KT88/)
if you go to KT88 try the Shuguang Black Treasure CV181s. They are a notch up musically from the GL KT88s which themselves are very good
Anyone have any thoughts on the Penta Labs KT-88SC tubes as a replacement to the 6550?
Just so everyone knows, the Winged C factory burned down. At least that's what I was told. ARC now uses 6550WE
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
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
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.
Rodman
Thanks that seems a sensible way to go as the price differential between NOS and current production for phase splitter and driver tubes, at least in Singapore , is much lower than the 6550 power tubes.
Will post my impressions post makeover.
Cheers
Pradeep
WOW- Singapore! I'll bet tubes ARE expensive over there. I've purchased quite a few Siemens tubes(in the past 12 years), from this vendor in West Germany. He's very reliable and sells excellent tubes: (http://myworld.ebay.com/audiotubes_de&ssPageName=STRK:MEFSX:SELLERID&_trksid=p3984.m1543.l2533) I started dealing with him long before he sold on eBay. Yes- Rolling preamp, driver and splitters is less expensive, UNLESS your tastes lean toward the pre-1966 Siemens CCa(I use six in my system), Tung-Sol CTL/6SN7GT round plates(two) and Sylvania CHS/6SN7W tall bottles(two). The sound staging, extension, air and liquidity of these tubes is addictive(and, YEAH- I'm hooked). I'm getting sick, just thinking of what will happen, when my personal stash runs out(OUCH). Looking forward to your impressions, post-swap. Happy listening!
Sunnyboy, my amp is an ARC VS-115 which originally came stock with 6550C tubes. Since then ARC switched out to the KT-120s, which is what I used now. Bought the KT-120s from Upscale Audio. In my opinion, the KT-120s better the 6550C tubes in pretty much every way. If your amp can handle the extra current demands, consider the KT-120s. But check with the factory first!
Rodman
Check out the Well Audio Labs (Singapore)site. I reckon the prices are competitive vis a vis some other online sites.
Bifwynne
Many thanks for the tip. Will contact CJ and hopefully get a response before I set out on my travels .
Happy listening
Pradeep
I have 20 low hour cryo'd Winged C's. I went back to KT88 and much prefer them for overall warmth and sweetness. Are the Winged C's hard to find since the factory burned down?
Arthur, Kevin Deal at Upscale just sourced a whole bunch of SED 6550 C tubes. Just bought one for my ARC Ref 5 linestage. Seems to work just fine. Price is still reasonable.
I procured a set of Genalex KT 88s from Well Audio Labs, Singapore,last week and spent the better part of the weekend comparing the 3000 hr+ Winged C 6550s with the new KT88s.What immediately struck me was that despite some 3000 + hrs there was little to choose between the 6550s and the KT 88s. There was a smidgen more smoothness and air in the upper frequencies. After extensive listening comparisons done with NJ-Come Away With Me lp, the KT 88s are superior in the context of my system and my listening preferences.
Many thanks for all your input/advise.
Happy listening
Pradeep
I wouldn't be a bit surprised if brand new KT88s sounded better than end-of-life 6550s, of ANY brand, in ANYONE'S system. Happy listening!