NOS KT 88s or GE 6550s

As far as comparing the Gold Lion to the NOS tubes, I have no idea what the difference would be. Going from KT88's to 6550's would probably be a big change. There are so many factors involved that its almost impossible to guess at something like this. If it was my call to make and I couldn't somehow do a demo, I wouldn't take a chance; espically if the cost is very high. CJ is a great company and if the tubes in your amp are stock, I would trust that the tubes are a good match. They wouldn't pick a tube that didn't sound good.

Now that I think about it, are the KT88's in your amp stock? The reason I ask is that I don't recall CJ ever using the KT88. I'm not up on their current models, though. The CJ amps I have owned in the past either had EL34's or 6550's.

You may want to give The Cable Company a call. They have a huge lending library of cables, accessories and components. I'm not sure if they lend out tubes, as well, but they have a very big selection. I've used them many times in the past and I find them to be very honest and trustworthy. Even if they don't lend tubes, they may be able to give you some useful info.

Zd542
Many thanks for your response. The CJ came 6 years ago with the stock Winged C 6550s. These were replaced with the KT88s based on advice from fellow Agoners and others. I have am happy with the sonics but have always been curious about the improvement that NOS tubes can provide vis a vis current production tubes. You are right that this is highly subjective and any opinion is valid only in the context of a system/room/musical preferences and priorities.
Would still love to share the experience of Agoners who have switched to NOS for their CJ or ARC power amps.
Pradeep

I do not own either amp but I do own an Octave V70SE integrated. Mine came with SED KT88's and I also ordered a quad of SED winged C 6550. The SED 6550 is a very linear sounding tube where the KT88 is a little warmer. Next I got a quad of the GL KT88 re-issues. The GL's fall somewhere between the SED 6550 and KT88's. Later I scored a quad of Tung Sol 6550 solid black plates. Wow what a difference. More like the SED EL34 - magical mid range ever so slightly rolled off highs and not much in the bass dept or power when compared to the SED or GL. The TS 6550 solid black and grey plate have the bass and the power the EL34's lack. Later I picked up a quad of Gec KT88's. Very linear but with a tighter low end and more 'sparkly' for the highs.

That being said I do not own or have even heard the GE 6550. So to summarize I have to say the SED 6550 - Gec KT88 and GL KT88 are all more 'solid state' sounding where the SED KT88 and Tung Sol solid black and grey plates are more 'tubey' sounding. Now if you like the Gec KT88 sound and want even more of the same try the EAT KT88's. Another KT88 that I have is a KR Audio branded Tesla. A hair more of the Gec KT88 but not quite an EAT. So if you prefer the SED 6550's the Gec KT88 is a big step up. Sorry I can't comment on the GE's but I'm trying to give you an idea of the differences between the SED 6550 - GL KT88 and Gec KT88's.

Last to me all tubes sound good but there are sonic differences between types and manufacturers. So types like 6550 or KT88 can not be lumped into a particular sound category. Another Great tube I have is the Ei KT90 type 2.

Sunnyboy, I have heard both the GE 6550's and the GL KT88's. IMO, the GE's are some of the very best tubes ever made. If you like midrange magic and the ability to drop down in the bass dept, then you will LOVE these. The GL KT88's are almost veiled in comparison. The SED 6550's are very very good and are a fairly close second to the GE's in the 6550 range. Only problem is the GE's are usually very hard to find in decent condition.
I say go with the GE's if your amp can use them.

Contact Ed at C/J and find out if you can put KT-120's in that amp.