Anyone Compared the New 6550/KT88s out there in their Amps?

[microstrip]

I have avoided posting about them, as I have a horse in this race - I will be selling a pair of cj LP275's monoblocks soon - but these amplifiers represent some of the best that cj have designed, the differences between them and the ART's are not night and day. They share most of the elements and design. I have used them with the KT150s' and they sound very powerful, but clearly musical with all the flavor of cj.

Most of the time when people say that circuits must be modified to use the KT150 they address getting all the power these tubes can deliver - they can operate with an higher HV than KT120's and give more power per tube.

 

[bonzo75]

Ok if you don't like Luxman and accuphase try the Berning quads, though rare to find, and Soulution. Not at a show or something though please

 

[dminches]

I recently purchased a quad of GEC KT88s for my Zesto BIA 120 amp. They completely blow away the Gold Lion KT88 reissues. While this isn't a real surprise to me, it does make me wonder why many reissues are inferior to older production. The same was the case for the JJ 12AU7s which were replaced with a quad of NOS Mazdas.

 

[Mendel]

I recently purchased a quad of GEC KT88s for my Zesto BIA 120 amp. They completely blow away the Gold Lion KT88 reissues. While this isn't a real surprise to me, it does make me wonder why many reissues are inferior to older production. The same was the case for the JJ 12AU7s which were replaced with a quad of NOS Mazdas.

A couple of reasons come to mind:
1. NOS tubes were made with materials that today would be considered hazardous so they could not be used.
2. The master craftsman tube builders (every major factory had a few in the 1950s and 60s) are gone, replaced by low wage workers.
3. Tubes are now a disposable product used manly by guitarists and home audio enthusiasts , whereas in the 1950s they ran all electronic devices so quality was more critical.
4. Due to lower worldwide demand, tubes must be produced more cheaply and efficiently to allow producers to make a profit. They can't afford to screen production as closely as before and toss out as many non spec tubes.

 

[dminches]

I knew the materials were an issue. However, I wondered whether China or Russian actually had any regulations about this.

 

[microstrip]

I chose KT-88s rather than 6550s for my VTL Siegfried IIs.

+1, not even close

What brand are you using? My VTLs have the originally supplied Gold Lyon, but they are approaching 1600 hours and I want to buy some spares soon.

 

[Ron Resnick]

I’m afraid I cannot tell you. I have never seen the amplifiers.

 

[Mendel]

After much research, tearing of hair and gnashing of teeth, I bought a used set of Psvane KT120 tubes for my Cary SLI-80. They were burned in for 150 hrs by Grant Fidelity and around 30 hrs by the original owner. I've put about 20 hrs on them and their biasing so far has been steady.

My previous tubes were the stock EH KT88's and I had no idea how shrill they are til now. The amp has the ability to change from 80 watt ultra linear operation to 40 watts triode (on the fly.) I had been listening almost exclusively in triode because ultra linear was too forward. Now, with the Psvane KT120, I prefer ultra linear.

They tick all the audiophile boxes; the amp's performance is better in every way.
Now if they'll just endure for a reasonable amount of time...

Hi ER.
Just wondering if your Psvane KT120s are still working reliably in your amp and holding steady bias.
It would be great if the answer is yes, they are likely much better sounding than the “Tung Sol” reissues.
My experience with the Treasure KT120 (from about 3 years ago) was that they sounded great, but after 2 months of use the bias became wildly unstable in two tubes of the quad.