So, several weeks ago I posted on a possible new KT66 failure I thought I had. I got help from members trying to pin down the culprit and thought I found it. I pulled the KT 66 set I got from DecWare and shipped the off. I replaced the original EL 34's and everything up until this morning seemed fine. Went to warm up my MKIV this morning and immediately noticed my left channel out. I having learned a little from the last episode I started to methodically switch tubes from left to right starting with the OC2's, same left channel out, then the OA3's, left channel still out, then moved onto the switch with the 5U4G's and got a light show from the right 5U4G, the one that was originally on the left and now both channels out. Main fuse fine, the OC2's appear out and cool, the EL34's still glow, the 6922's are powered, the OA3's are lights out and cool.  No glow from the 5U4G's but they get hot. No sound left or right now. Hopefully to recap:
OC2's no glow appear out
OA3's no glow appear out
EL34's Glowing
5U4's no glow, but hot
6922's Glowing

I can't quite get a feel for this because now both channels out after doing the 5U4 switch and getting a light spark from the right one after switch.
Another note, before the shop shut down Sarah told me that Steve checked out the KT66's I sent back and they were all 4 fine, so it seems something in the KT66's (draw?) might have been pushing towards whatever eventually happened because all has sounded good for weeks since I sent back the KT66's to get checked.
 The good part is hopefully I can reach Steve tomorrow and get his thoughts, maybe just get the entire thing in, get the anniversary mods done and new caps, and have him take a look at the entire thing. Any thoughts? It has me baffled, but that is feat easily accomplished when it comes to tubes!

Happy New Year to All!

Best,
Scott

Hi Arch,

 Thanks for the reply, since I posted, I have pulled out my pelican case and decided to ship it tomorrow rather than mess around. I have only a set of KT66's as extra and they are at DecWare waiting to be shipped with my Zrock2 Modded which should go this week I'm hoping. Since something weird is perhaps happening, and I want the mods, off it goes!
I was hoping to have a listen to my ZROCK2 before shipping off my MKIV but I have Sony HAP1s that will keep me in tunes, it drives the DNA2's just fine and actually is listenable thanks to what a great speaker the DNA2's are...just not anything like the MKIV pushing them.
 All in all, not the end of the world, I'll manage and am glad I didn't sell the Sony, maybe it'll be a good reason to get some Betsy's for a second system at some point, but then I'll want a 25th Anniversary to drive them and on and on and the Rabbit Holes deepens and widens
 Guess I need to get some backup tubes on the way when the MKIV gets shipped back, it'll be fun to get the amp back and have the ZROCK2 ready for it, with the ZTPRE close behind. A good thing to look forward to for the new year.

Best to all, have a great New Year, CHEERS!

Scott

 I doubt it is anything other than a bad tube, and more than likely if not, something I did, not sure what, but I probably helped it along!
 I'm all set sending it in, it'll be back soon enough, with caps and mods all set to go, so I'm excited.
 It's in the Pelican and the tubes are boxed, my UPS guy will be here tomorrow to pick them up.

Best,
Scott

Arch,

I did get the full mods, it happens it was in QC when they closed for Christmas, so I'm guessing it'll get packed up and shipped to me this week, my MKIV is all packed and ready to be picked up tomorrow to get checked and have Bees Wax Type II caps installed and then full anniversary mods. Can't wait to get it all back together, then follow with the ZTPRE which I ordered in mid October so it's working it's way on the list. This actually is seeming to work out just fine, and a lessoned learned on having a spare unit on hand to keep the music playing. It would be a tough wait with nothing!

Best,

Scott

So far no mods for the ZTPRE are announced. Looking at the interior I'm not sure they would fit in the chassis, but Steve might find a way. I have now decided to use one instead of a CSP3-25 in my main system, so I don't really feel it's necessary, but we'll see what Steve gets around to.

Scott, you're going to have a killer system when it is all in and settled in!

Sure, Steve might weigh in here and I'm sure he might work some magic.  But I confess I think the ZTPRE is so perfect as is--transparent and "breathing"--that I won't be sad if it never changes. You may find it the same way.

And there ends the speculation!
Thanks Steve.

Hope you had a great holiday and got some rest, your work seems cutout for you in 2019, what an amazing 2018!

Best,
Scott