Replacement tube suggestions for Premier 12 monoblocks

[Big Dog RJ]

That's a definite Justubes!

Another fantastic KT series tube, which are hardly ever mentioned... Back in the day, when i was using the Manley Labs reference 350's, the original 6550's needed replacing. Eve Anne Manley, President Manley Labs, recommended that we try out the new KT90 EI tubes. She claimed that it will add more life to those vintage monoblocks, and boy was she right!

I'm thinking that when the 6550 series tubes were pretty much standard used in CJ and ARC gear, this was the industry standard along with EL34's and KT88's used in specific types of push-pull configs. I first heard about the KT90 around May 98. In 99 that's when I received shipment of 16 new KT90's and so we were very eager to try these out. The power and dynamism really shifted gears, and then we realised how good these KT90"s made such a positive difference on our amplifiers. Back then KT120 & KT150 weren't even heard of... now they've become the industry standard on all high powered amplifiers using push-pull config.

Manley Labs still uses the KT90 series as their preferred type of output tubes in their top line monoblocks. I guess they have their reasons.

Cheers, RJ

 

[justubes]

Yes,

I refer to the Yugo EI KT90 and not the EH KT90.

Manley and VTL had to change to other tube types as EI's were no longer available as the EI factory was bombed.

I hear the same back then, Manley and VTL had to say the other tube types were better in their amps, only because the EI KT90's were no longer available! But behind know the EI KT90's were the best!

It was the same for Jadis.

The NOS GE 6550s that came with my CJ's, were barely passably sonically after comparison.

EH may not have started producing EH KT90's, which i have never tried.

 

[Big Dog RJ]

Oh! I didn't know that the EI Yugoslav tubes were no longer available. In which case I wonder which versions Manley Labs are using currently in their monoblocks.

Not sure if EH were to ever produce this tube, the tooling required would be quite extensive and this has been the main issue of tube manufacturing moving forwards. Some brands like EH and Sovtek have vast tooling libraries, which enables them to make a range of tubes. However, in many manufacturing centres this is not the case and tooling equipment is getting much rarer now, with some tube types in non-existance due to a shortage of tooling.

Would be interesting to learn what the future holds for such manufacturers if they're going to be focused on making tubes. I heard that Western Electric has just announced a new production base. Hope they come up with top quality because WE were know for their tubes.

Best, RJ

 

[COF]

I bought my 12s in the late 90's. They came with the original GE 6550s. Later on when those weren't available I just went with the CJ-suggested Tung Sol 6550s. I found the Tung Sols retained the essential sound of the amps and I was happy. Then when I needed re-tubing last year I decided to try the NOS Svetlana Winged Cs since Doug of Doug's tubes had stumbled on to a big stash and had a whole bunch available at the time.

The sound was very similar to the Tung Sol's they replaced so I can't say for sure what difference there may be, except I did have the impression my system had never sounded better. So punchy with a great sense of neutrality (balance, clarity) yet still tube-tone.

Then I tried KT120s in the amps and LOVED what they did - in my case they just made the sound "bigger" in every way - a sense of deeper bass, expanded soundstage size and depth, sonic images seemed larger and more substantial, and detail seemed very fine. It actually sounded a bit more "tubey" than the 6550s. A bit more laid back all around.

After a long time with the KT120s (and experimenting with different input tubes) I threw the Winged C 6550s back in the amps a couple days ago. Just as I remembered, everything sounded smaller, more compact, more focused, but also more dense, dynamic and punchy. The sense of a drummer whacking a solid object between the speakers was that much more realistic. Tone was a bit more extended and forward, making cymbals and similar shiny transients pop out with more presence. Brass instruments sound a bit more like real instruments pushing air towards me vs "see-through."

So for me in going between the KT120s and 6550s, it's a choice between KT120s: "feeling like I'm immersed in the acoustic hearing full size instruments, the back wall behind the speakers just melting away" vs "the musicians brought closer in to my room, but sounding a bit more like live musicians."

 

[Big Dog RJ]

Good stuff COF mate! In fact I've just checked with Manley Labs, they're now using the EL34B version in their Neo 250 monoblocks, and the EHKT90 in their Neo 500 monoblocks. Looks like they've changed over from the EI Yugo version, as you mentioned no longer available...

Very glad to hear that you're enjoying those Prem12's, with the 6550C's that should be one mighty fine sound! Those Premier series amplifiers are what made CJ well known and stand out from the crowd. It had a signature sound that was extremely immersive, highly addictive and one that not only presents power and control but also a fine sense of balance with finesse. This series was later discontinued, to give way for a more neutral sound, allowing more of the music to flow, capturing closer aspects from the original recording. Using fewer parts, incorporating the shortest signal paths, and using very high-quality parts, yielded better results. However, the most ironic thing is compared to what they've done or achieved in the past up until now, their amplifier circuits are based on their original 60's design. This is referred to as the Classic tube circuit and CJ executes this circuit to perfection, so they have just stuck to it since! Each time my trusted techie opens up a unit for service, he notices the same base circuit, and it's very easy to service and get round, compared to the very complicated and tricky circuits of other brands.

Compared this to ARC, and their gear is very different. Newer designs, real breakthroughs with some remarkable products but not all of them are up to the standards of a certain quality of finesse. Most recently I had the M160's on trial for a few weeks, whiles my CJ amps were being attended to. Although I did like their performance & sound, for some reason I just preferred the REF75/se... I found it to be more musical compared to the larger amps. Maybe it's something to do with those bigger trannys, I don't know.

In contrast to that, with CJ's Premier gear and their newest offerings, that signature sound is consistent right throughout. The only areas that differ are in power and controlling difficult loads. That's the main reason why I did all those mods over a two-year period; and another reason why I would never sell them! Absolutely fabulous!

Cheers mate, and enjoy those fine tunes!
Woof!!! RJ