I have had my zen for about a week. I put some new Mullard el84s in just to try them. I quickly went back to the originals as I didn't like the el84  I'm thinking about sound as much. my last amp was an el84 amp push pull so I know that sound. my phono pre is a zp3 and I changed the tubes to nos military JAN 5y3 wgta oa3 and 12au7  Big difference!  I'm thinking about changing the rectifier tube on the Zen

Thanks for the replies.  The improvements with the input tube change and rectifier tube change were so impressive that I don't want to leave any tube options unexplored.  On the other hand, you could easily sink down a rabbit hole trying different tubes.

One great thing about the SuperZen is that there are only 4 tubes total so you don't have to take out a mortgage to try new tubes.

Hello Ellsworth,
I know this thread is old, but I felt I should respond after recently reading about the Valvos.

I'm with Lon ( at least up until I modify my CS with the CCE mod ), on the EL84 tubes. In my old SE84CSEX they were by far the more musical tubes compared to the SV83 types. For the record my SV83 types are late 70's 6P15P-EV gold grids, and my EL84 types are the 6P14P-EV late 70's vintage. those Rusky EL84M types are GREAT tubes.

FWIW, I can guarantee you that those early 60's Valvos you sourced off of Ebay for 15.00 were not up to snuff. A pr of Valvos that old that still tested good ( let alone NOS ) would approach three figures.
The amp sounded like it did because those Valvos were old and tired.

Try to get a couple of pair of the 6P14P-EV types, and also the TAD tubes that Lon favors. While I've never heard the TAD tubes, Eddie V. and I had many discussions about them and he was very high on them. That's good enough for me.

Cheers,                  Crazy Bill

Hello Ellsworth,
Before you buy some stuff you're not sure of, let me make you an offer.

As long as you promise to send anything you don't like back to me in a month or so, here's the deal.

I'll send you a pr. of the 6N14P-EV ( late 70's vintage ) true EL84 equivalent. Great tubes.
one pr of the 6P15P-EV late 70's to compare.

I'll also send you a 70's vintage 6N1P-V1 for the driver tube. Another great tube.

The RCA 5U4 rectifier is good. Not as good as the NOS Rusky black plates. I'll send you a early 60's vintage Rusky black plate  to compare.

Let me know.

If you want to keep any of them we'll figure it out.

Cheers,  Crazy Bill    

Hello Sam,
thought I should post this in the forum for others to see.

Since my SE84CSEX is in pieces in the garage, and I never have enough time to rebuild it, I've been looking for a used Zen to hold me over until I get the Decware rebuilt and my 2A3 project finished. I struck paydirt a couple of weeks back, as I was able to purchase a 2002 vintage SE84CS from Parts Connexion for $ 399.00. It came with a flame maple base and a few decent tubes.

I immediately put the vintage Rusky tube set that I used before I took the CSEX apart ( maybe 6-7 yrs ago. ). A black plate Rusky 5U4G ( early sixties ), late 70's 6N1P14-EB, and the 73's vintage 6N1P-V1. I also used to use a SLN specced cryoed 6N23P-EV that I swapped w/ the 6N1P as the mood struck me. Can't find em right now, but I will eventually.

It made beautiful music and I'm trying to find as much time as I can to spin some vinyl.

Well no grandkids today, so when the wifey heads off to work I take the SE84CS to the garage to do some work. Here was the plan.

Since I have read all of the noise about the CCE mod, I wanted to compare the 6P15 varieties to the EL84 with the CCE mod. So the plan was this.

First, I was going to leave the present WIMA coupling cap in place, but rewire it to act as the CCE cap. Since I have a pr. of the Jupiter copper foil caps here that Steve uses, they were going in. So I took the bottom plate off and got ready to do the mods.

Then I saw the little black 0.1 uf caps installed between pins 3 and 6 on the output tube sockets. Someone had already done the CCE mod on this baby. So I closed it back up and took it to the house to compare the two tube types.

First put the 6P14P-EV in a for a couple of minutes and listened to a Cohen track I know very well. Sounded phenomenal.

Changed tubes to the 6P1P15-EV and played the same track.

Not much to say except I was stunned. When I first read Steve's description of how good this mod is, I was of course skeptical that it could be that profound of a change. I'm not anymore. No more EL84 types in this amp  for me.

Cheers,                       Crazy Bill