Recent News:

Premier 11 / KT120 tubes

Do It Yourself - everything from building your own hardware to room
treatments.
Post Reply
User avatar
Wildcat
Advanced
Advanced
Posts: 35
Joined: Tue Feb 16, 2016 10:02 pm

Premier 11 / KT120 tubes

Post by Wildcat » Fri Apr 28, 2017 8:56 pm

I landed a Premier 11 today (not the 11A), at quite a good price. I gave it a good cleaning, touched up a few small nicks in the black paint, and polished the gold top and front panels. It's looking pretty much like new!

The tubes are of unknown age and origin--three of the four 6550s are missing the lettering, and the fourth is so faint that I cannot make out a manufacturer. The 6FQ7s are mismatched (two different brands), and the 5751s claim to be "JAN" tubes with green lettering, supposedly made in the USA. The amp is dead quiet, but I noticed that there is a channel imbalance--I had to adjust my CJ preamp so that the right channel is four stops less than the left, in order to center the image properly. I infrequently noticed a very slightly "ragged" sound on strong high frequency content, which also makes me believes the tubes may be past their prime. (Or maybe this thing is even more revealing than the Nelson Pass amp I had prior.

No problem, as I am already working on getting a new set of tubes. The KT120s have a sound that I like (I heard plenty of them at AXPONA last weekend), but they are a half inch higher than the 6550s and some of the other KT## tubes. I may have slightly less than half an inch of space between the bottom of the cage and the top of the 6550s.

So, here is the DIY part. I want to run the amp with the cage on it, mostly for safety reasons. I do not want to alter or bend the cage (it already has a slight warp to it, which I have mostly straightened). What I am thinking of doing is removing the side panels, and installing a black spacer of some sort underneath the side panels where they are bolted to the main part of the chassis. That would give the entire cage and side panels the needed lift, and should be stable enough depending on what kind of spacer I come up with. That gap will probably be mostly unnoticed, as the amp is on the large, open bottom shelf of my rack.

Has anyone attempted anything similar to this?

I will attempt to post photos once I get the new tubes and rig up some sort of spacer.
C-J PV-14L/C-J Premier 11/Vandersteen 2Ce

User avatar
Wildcat
Advanced
Advanced
Posts: 35
Joined: Tue Feb 16, 2016 10:02 pm

Re: Premier 11 / KT120 tubes

Post by Wildcat » Fri Apr 28, 2017 9:53 pm

Additional question--has anyone ever adapted a C-J power amp with an IEC power cable input? The cable on this amp has a spot with electrical tape on it to cover some damaged insulation (not to bare wire though), so a future project might be to replace the cable, or adapt it for IEC so I could plug in one of my better power cables. (I don't know if C-J would be able to do this at their service facility.)
C-J PV-14L/C-J Premier 11/Vandersteen 2Ce

User avatar
admin
Site Admin
Site Admin
Posts: 1130
Joined: Tue Jan 03, 2012 1:50 pm
Location: New Hampshire, USA
Contact:

Re: Premier 11 / KT120 tubes

Post by admin » Sat Apr 29, 2017 10:24 am

Nice score with the Premier 11.

As to your comments above. Sounds like new tubes would definitely be a good try.

In terms of raising the cage, the cheapest and easiest way would be a "screw spacer". Just google it, you can find many styles and they cost under a dollar if you want the cheap plastic ones, or they sell nicer metal spacers which can be put in more permanently and you don't have to worry about the original screw length.

You can mod the unit for an IEC connector. My CJ Evolution 2000 amp has such as mod for an IEC connector. My CJ DA/2b also has a cord replacement.. You will need to cut an appropriate sized hole for the mounting of the connector and just attach the power wires. Pretty simple.
-admin
Home Theater in Member Gallery
Conrad Johnson Owners.com Main Page

Current Conrad Johnson Equipment in System: Evolution 2000, PV-12L, and D/A-2b.

User avatar
Wildcat
Advanced
Advanced
Posts: 35
Joined: Tue Feb 16, 2016 10:02 pm

Re: Premier 11 / KT120 tubes

Post by Wildcat » Sat Apr 29, 2017 11:51 am

Some locals and I were just talking about this at AXPONA--a metal punch that would accurately cut out the opening for an IEC connector. On the Premier 11, there is enough room for one, but not much room to work with on either side since it is so close to the edge of the rear panel. I also wonder if it is "C-J approved." In reality it doesn't matter to functionality, and it is so minor a modification (not changing any circuitry) that I don't think it would affect anything.

I had considered seeing if they could upgrade it to the 11A, but it is so silent now that I don't see an immediate need for it. (The "A" revision was to add a filter to the bias LED circuit to reduce noise.)

Thanks for the tip--I completely forgot about those threaded standoffs. I have used those with circuit boards and computer motherboards in the past. If I can find one in the correct height with the proper threads (which I can measure here), that should work well enough. As long as they are in black, and nicely finished, they would work out fine.
C-J PV-14L/C-J Premier 11/Vandersteen 2Ce

Post Reply