AUDIO FORUMS >> General Discussion and Support >> Tubes for my new ZMA

Message started by stone_of_tone on 12/19/13 at 18:30:31

Title: Tubes for my new ZMA
Post by stone_of_tone on 12/19/13 at 18:30:31

KT66 = available from various vendors

KT120 = available from various vendors...and I will order a matched quad when my ZMA is on the Test Bench (per real time build sheet).

OA3 = I have two pair of RCA OA3' the pair Steve will ship with my ZMA.
Question: am I assuming correctly that the OA3's should last 10,000+ hours?

6N23P-EV = shipped with ZMA should last 10,000+ hours as Steve mentioned in ZMA product information.

Further thoughts, if any of the Tubes fail that are shipped for my ZMA:
I will have KT120's on hand, while I wait for a replacement(s) KT66 from Decware.
I will have OA3's on hand, while I wait for a replac...... .
I will have four 6N23P-EV's Cryoed from I wait for a replac........ .

I have had only one (1) Tube fail on me in 12.5 years of using Tubes.

However, I want to cover my butt...when this Music Making Machine (ZMA)...comes out of its Pelican Case...and in to my Listening Room. -S

PS-plus, I want to compare the Cryoset 6N23P-EV's, to the ones coming with the ZMA.  

Title: Re: Tubes for my new ZMA
Post by stone_of_tone on 12/19/13 at 19:40:13

Oh, I should add....."Rectifier's....I spit on Rectifier' with ZMA"!!  NO Sag n' no lag.

Picture Dr. Evil, with pinky at Seth Green rolls his eyes at Dad!   Cheers, -Stone.

Title: Re: Tubes for my new ZMA
Post by Lon on 12/19/13 at 20:07:20

Thinking like a risk manager! You'll be covered, good move.

Yeah, I would guess you would get that and more out of OA3s.

Title: Re: Tubes for my new ZMA
Post by Lonely Raven on 12/19/13 at 20:12:29

High-Five brother of Tone!

I'm curious about the Cryoset vs stock myself. While I'm very aware of how "cryogenic tempering" can improve the physical grain structure of metals, I'm somewhat skeptical about cryo-tubes. Mostly because I have trouble believing they can get vacuum tubes to -300 degrees without any issues.

While I won't be shelling out for power tubes right now, I've got an extra pair of the OA3, and several sets of 6922/6DJ8 types handy. I'll eventually get a spare set of KT66 after I get all my Herbie's tube dampers and iso-cups and all that ordered and installed.

Title: Re: Tubes for my new ZMA
Post by Lord Soth on 12/19/13 at 23:41:20

Dear Stone,

From various tube literature on VR tubes, the 0A3s are supposed to last forever.
However, on my MK4, I noticed that the silver getter flashing of the OA3 and 0C2 are steadily receding. This is normally not a good sign.
So I think that lasting forever part could be hyperbole.
I bought a few more extra pairs of such tubes since they are still not too expensive.

Any other existing VR tubed Decware amp owners out there care to comment on the longevity of their VR tubes?

Dear LR,
I've used Cryoed WE 396as from Tubeworld and Cryoed 6N1P-EVs from Cryoset so the tubes definitely can survive the ordeal.
In theory, only the toughest tubes can survive this process.
I've never done any AB sonic comparisons of Cryoed vs non-Cryoed tubes though.

Title: Re: Tubes for my new ZMA
Post by stone_of_tone on 12/23/13 at 19:25:42

I'm with you Lsoth, whether the Tubes are Cryoed down to -300, or in the ball bark at least... . I figure for all of 19 bucks more for a quad of KT120 from Cryoset vs. BOI Audioworks...I'm going with the Cryo.

"The thermal dissipation properties of the metals are improved, reducing hot spots and further contributing to extended life and improved performance. In addition, the physical contraction of the metals while under the deep freeze imparts a mechanical compression on the metals that contributes to improved signal transmission quality and speed".

I believe this to be true! Why?  I can hear the difference, and find my Cryoed -EB's (I did a group buy back in 2005 with Forum members here)...are better than the stock ones. I love my Cryo pair in my SuperZen CKC. For my SE84CS, sorry Cryo EB's....only NOS Svetlana the Original SV83 will do.

Cheers, Stone....waiting for his ZMA like a big Kid!

PS-just throw out the mumbo-jumbo quote I put above. The bottom line is: subjectively, do I think the Cryo sound better = yes. YMMV.
Just like the fact....that I am in the less efficiency camp for Speakers with Decware...and also love premium Cables with Decware.

Title: Re: Tubes for my new ZMA
Post by stone_of_tone on 01/14/14 at 16:30:52

I picked up some RCA 0C2's for my Torii IV coming in March. However, they arrived in RCA NOS boxes....but they are Motorola's. All good?
Please enlighten?   -S

Title: Re: Tubes for my new ZMA
Post by stone_of_tone on 01/14/14 at 17:18:38

Well da, after checking the other three boxes (I bought two pair)...the other three 0C2's are NOS RCA's. Just the one out of the four is a Motorola 0C2 (accidentally) in a RCA NOS 0C2 stamped box.

CHit happens.  The Motorola's & Ratheon NOS 0C2's kick arse too.  So, no worries.

Party on on Garth.    -S

Title: Re: Tubes for my new ZMA
Post by Palomino on 01/14/14 at 23:06:58


There is a cryo operation in the Chicago area that does tubes (and anything else you want to chill) so if you wanted to experiment with existing tubes, you could.  I think he has a $30 minimum.  Not sure he goes to -300 though.  

I had him do some Hubbell 5262 outlets for $5 each and thought it made a difference.  His charges were pretty reasonable.  Less than a week turnaround.

As for the cryo tubes, I've never done a side by side comparison, but they are pretty smooth sounding and I'm telling myself its the cryo.  Enough so that I'll probably get the next set I buy cryo'd.

Title: Re: Tubes for my new ZMA
Post by Lonely Raven on 01/15/14 at 03:36:44

If it's the shop I'm thinking of, I've used them for Porsche parts many moons ago. I think it was called -300 ?

You have the name/address of this shop? I might drop some stuff off with them to be dropped in the vat...maybe even some guitar strings and other stuff I want to mess with.

I'm thinking about trying some VR90 tubes in my ZMA - mostly because I like the blue glow.  :)

Title: Re: Tubes for my new ZMA
Post by will on 01/15/14 at 16:17:52

I have done direct comparisons with JJ6CA7s, cyro and not, and with Tungsol EL34B. There are other factors, as the tubes did not perfectly match quad to quad. In both cases the tubes were more articulate/defined, smooth, open, etc...cleaner in terms of less subtle grunge, a little more sense of extension, slightly tighter throughout, especially useful for bass...sort of like a good power cord compared to a less good one. It cleans up the "fuzz" a bit, while making all the things a tube does a little better.

I have also cryo'd a bunch of inputs and VRs and similar results. I definitely hear the cryo thing, and though it is subtle in some ways, it is a useful improvement for me, always working that last few percent. Question becomes, do you like these qualities or is the slightly softer non-cryo sound more suitable to your sound. These qualities can be good depending on system and preferences.


I have some RCA OC2s that came in a motorola box...opposite scenario of yours.. Makes me wonder if they are the same tube but I can't compare since mine are RCA labeled and look just like my other RCAs.

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