My birthday is coming up in 2 weeks - I'm thinking about getting some tubes for the ZMA to play with. Anyone do any tube rolling in the ZMA yet?

I'm thinking about some Cryoset  Super Cryo 6N1P-EV

http://www.cryoset.com/catalog/product_info.php?products_id=251&osCsid=8ead1fd8e...


I might be able to swing a quad of Gold Lion KT-66. But I don't think I can afford both pre- and power tubes right now. So I'm just pinging the family to see what others have had good luck with. Either way, I'll update this thread with some thoughts on tubes I've tried once their burnt in a bit, whatever I get.

It's funny most of us ZMA lovers are standing pat with the tubes.  I simply didn't think anything was wrong with the sound.  I also wanted to drive the quality of my preamp higher so I put nice NOS tubes in that.  The sound I'm getting now along with a couple of cable swaps is so good changing tubes on the ZMA hasn't entered my mind.

I'm open to be persuaed however.   If you try something that you really like, we are all ears.

I'm considering trying some of these.

http://www.upscaleaudio.com/matsushita-national-pcc88-7dj8/

Yes, Steve did say the 6N23P-EV was the tube for the ZMA. I've already spoken with him - and he says in my case I should try out the 6N1P. Maybe some 6DJ8 as well. I don't recall all he said as when we talk in person we talk at length and tend to wander, and on the phone we're super brief and to the point - that along with my terrible memory, well, I tend to only retain key points. LOL

I've got the Nationals and the Super Cryo 6N1P on the way. If I find myself going back to stock tubes like I kept doing with the little Zen amp, then I'll flip these tubes in the forums for only a few $$ loss. It wouldn't be the first time I tried something I didn't like, only to move on. That's part of why I'm pinging the family to see what others have experienced. I really think the ZMA is great as is, I'm just curious.  :)

I decided to do some tube rolling and have basically followed Steve's advice in the ZMA user guide. Try a different brand of KT66's and 7DJ8's in place of the 6N23P-EV's.

I decided to go with a quad of cryo Telefunken PCC88/7DJ8's from Upscale Audio. I have a Telefunken E88CC/6922 in my Taboo Mk3 and am very happy with it. The PCC88/7DJ8's are yet to arrive and based on previous experience it will be a few weeks yet.

For the KT66's, after some deliberation, I've gone with Harma-Cryo KT66-Retro's from Watford Valves here in the UK. I suspect they're re-badged Gold Lion KT66's that have been put through a rigorous testing, grading, burn-in and matching process. They arrived this morning.

If I'd heard the Harma KT66's before I'd ordered the Telefunken PCC88's I might not have ordered the PCC88's. The Harma's sounded good straight out of the box. There was nothing wanting. A superb valve that make's the Tung-Sol's sound course and unrefined by comparison.

Looks like Watford will ship to the US - so that's an option for us.

OK, so I went a little overboard, but I felt I'd treat myself at least a little for my birthday...I'll just be paying for it later.

I went with a quad Cryo Golden Lion KT66, a pair of the Super-Cryo 6N1P,  and a pair of those National 6JD8.

I also have some lightly used 6JD8 in my stash from trying them out on the Zen amp - they were a bit dry there, but worth trying in the ZMA. I just doubt they are balanced and all that, so who knows if they are a good example to put into the ZMA.

Re: pairs - yes - I'd need to ask Steve which does what (damn faulty memory of mine), but the outside tubes do something different than the tubes between the KT66. One set is an input tube, and the other I think is maybe a drive tube or splits the signal to the KT66 or something. Like I said, I don't recall, so don't quote me. I just know they do different things.

Plus, I couldn't afford quads of input tubes and wanted to try two different sets. So this is my compromise. I'll clarify more once I get the tubes and ask Steve what the difference between those preamp tubes is (or he'll post here to clarify).

Seriously, sometimes I wish I brought a tape recorder when I talk with Steve. He imparts so much information on me when we talk, and I'm really good with understanding concepts, but specific details often get lost. It's just the way my brain works unfortunately. If I actually had a decent memory, my IQ would jump 20 points....

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LOL - yes exactly!

So, I pulled out my box of "audiophile" tubes - which is everything that isn't slated for guitar amp use. Right on top I see a pair of 6DJ8 with GE logos, but the notes with the tubes says Telefunken! So I've popped these into the position between the KT66 and it sounds great. But then my setup has sounded exceptional lately - so I can't place if the Telefunken are really making any difference. I really need to do some A/B testing at listening volume, but can't do that for a few days.

Yeah, it's probably going to be a while. I forgot I'm away for 3 days for a wedding in Brianne's family this next weekend. Plus I think I need to burn some of these NOS tubes in before I can really judge them. I'm not sure how long that takes for these preamp tubes to bloom.

Those cryo'd 6N1Ps are going to take quite a few hour to bloom!

Charnwood,

I have seen a few different Telefunken PCC88s, and suspect there are more. One is Siemens made, which I have a pair of, the other...not sure, but both of mine needed some burnin to clarify and solidify the bass, so I suppose it is possible this could be the case for yours.

Also, comparing PCC88s in general, I think you will find them more extended feeling on top than 6N23Ps. An open, detailed, and  textured sound is characteristic of PCC88/7DJ8s in my experience even though they all have their own overall character.

I have been using some Miniwatt labelled early 60's Amperex PCC88s in my Torii MKIV with Gold Lion KT66. These are pretty warm and deep for the tube type, and are sounding great here.

I do favor OB3s though, which are more open and less dense than OA3s, and there is a bass tightening/reducing switch on the Torii. No bias adjustment here though. I wonder what happens if you lower the bias on the Harmas?

The Harmas will continue to refine also based on my Genalex...

I just ordered some National PCC88's. Thanks Charnwood, LR an will. I was told too...that these will be magic with Tong-Sol KT66's. ....extension on top that I like. I do also have a quad of the 23P's Cryo put away as well.

I have Speakers to break in and my P3 continues to burn in... . Then, I will put the National's in.

Listening Room:
Room Treatments from Michael Green & Home Brew
Sony as Transport
Illuminati D-60 (.5 meter)
Chord Chordette QuteHD DAC ---~or~
Audio Alchemy front-end/Revelation Audio Labs Prophecy Cryo-Silver i2s
Kimber Select KS1030 IC RCA (.75 meter)
Decware CSP3 w/Jupiter Caps
Kimber Select KS1030 IC RCA (.5 meter)
Decware Zen Mystery Amplifier
Kimber Select KS3035 Speaker Cable
Acoustic Zen Adagio Speakers
XLO Pro Power Cords to CSP3 & ZMA
PS Audio P3 Power Plant / Pangea AC-9SE from wall to P3

Decware SE84CS (w/NOS Svetlana SV83's from the 1980's-not the New Sensor knock-offs) & Decware Super Zen CKC...when SE Pentodes run in Triode/Decware Style...needs to be in the System!

Decware 6C33C SET Mono-blocks.....pending 2015

Yes I can only compare charcteristic qualities of tubes not having a ZMA. But I have done a lot of that! In this context though, there is an electronic difference between the MKIII and MKIV to the inputs, and this does seem to effect the sound of all inputs, including PCC88s. They seem bigger and fuller in general in the MKIV, but still have the open, textured quality I love.

I wonder what Steve says about PCC88 sound in the Mystery amp. It may be that the voicing choices, the power to the inputs is also different than a Torii MKIV...???

That the Telefunkens sound great with the Tungsol KT66 in Charnwood's setting, and thick with Harma/Gold Lions.....And likewise LRs first impressions with Gold Lions and GE telefunkens....seems like this could be a borderline.

I remember when I sent Steve some unburned in cryo'd 6N23Ps to check out some years ago (and me with bass issues) he said something close to: no wonder you like them, they don't have a lot of bass! On listening to them after he sent them back, I realized the bass does develop over time, as the pair I was using was the same tube but well burned in, and had more complete and musical bass. But I have not compared them directly to other types myself. Charnwood's and LR's first impressions with Gold Lions seem to support less bass from the 6N23Ps though.

Like Stone found....From the Mystery Amp manual:

"Due to the direct coupling between the two smaller tubes we recommend they be of the same type and be matched from side to side. 6N23P is a dual triode, so actually two tubes in a single bottle, which is why it’s desirable to have both halves of the tubes match. If you can’t find 4 matched tubes like this, you can get by with two matched pairs. Simply make tube location A11 and location B11 match. Then do the same for A12 and B12."

Looks like the front one, 12, is described as the input, and 11, between the power tubes, as a phase inverter. It would be interesting to try alternate tubes in one position with stock in the other, then compare them to the opposite arrangement...see what phase does and what input does!

Lots of warning about discharging the caps before tube rolling too, especially for the OA3s.

Unlike the MKIV where the OA3s filter the power to the Power tubes, and OC2s filter the inputs, best I could tell from the manual, it looks like the OA3s filter the inputs on the ZMA, also saying there are not alternatives to the OA3.

I look forward to you all's impressions and experiments with burn in!

I had some good-new/bad-news last night.

I got the Nationals in, and had an hour or two before Brianne got home, so I figured I'd play with the 6N1P and Nationals.

Well, I'm pulling the preamp tubes out of the boxes, the KT66 were already installed the other night. The Nationals slip out of their boxes no big deal, then I'm trying to pinch and pull the 6N1P out of their boxes, and one POPS on me!! It popped like it was a fragile glass Xmas ornament!

In my 30+ years of dabbling in tubes, I've never had anything like this happen...now I'm a bit clumsy, and I have strong guitar player hands...but I've never pinched a tube to death! So I quickly E-mail Ron at Cryoset - sent him a couple close up photos of the popped tube on my kitchen counter where I have enough light for a camera phone photo...and the short version, he basically said I dropped it on the granite counter, it's my problem. It sounded like a very curt piss off. I told him I'm sorry that he's probably had to deal with weirdos in the past, but I wouldn't have bothered him with this if I didn't feel this was my fault, and it's too bad he's not going to help me. The only response I got was "send them back". So we'll see how he handles this.

I've never really had cryo'd tubes before - but I understand how the process works as I've had many other things cryo'd over the years. In fact, many of the tube stores use a shop I used some 20+ years ago having Porsche parts and guitar parts cryo'd. (yes, I was way ahead of the curve there). But I don't know how glass envelops handle the cryo treatment-and asked Ron if it sometimes makes the tube fragile...no real response to this of course.

So anyways, the 6N1P are down and out and I'm sending them back tonight. I should just buy the pair in the Classifieds now and tell Ron to Piss Off, but I know he's probably just drawn out from too many idiots out there. I'm hoping we can figure this out, even if we split the cost or something. I really feel like I just got a bad tube - I mean, seriously, since when does a tube pop by hand pressure?

So the ZMA currently has the Nationals in the Input section, the stock 23P in the PI section, and the Golden Lion KT66 in the power section. Right now I don't really like what I hear - but everything is still breaking in. I'm out of town for a few days, so I'll follow up when I get back.

Well it was your recommendations that lead me to go try the GL KT66 and  6N1P from Cryoset - so I'm hoping I see the same improvement that you do; though I recognize that you and I have different ultimate goals in our final sound.

I totally see where Ron is coming from, I've never had a tube pop like this, and I know he's handled it after the Cryo treatment, tested it, and documented it. I can only speak to what happened when I tried to pull it out of the box. I also made a point to tell him that I had zero damage to the packaging - which makes this even harder to believe, but it is what it is.

Well, I'm back listening to the Harma KT66's with the 6N23P's and liking what I hear. This is one smooth sounding combination, and I don't mean in the glossed over details sense.
I discovered that I have a problem with my Tung-Sol KT66's in that the bias of one of the tubes is way off. Bad enough that I can't set the correct bias on the ZMA. Not sure what I'm going to do about that.

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Try swapping sides, and if the problem follows the tube, then it's for sure a bad tube.

LR, have you tried the Nationals 7DJ8's yet? I had to get a pair in last night an I'm listening this morning. They are as Kevin described with only 11 hours on them...smooth/extended top an bottom with no exaggeration, yet very articulate and not taking away from transient attacks....an ohhh, the timbre an 3D addition of Air. I am very pleased. I am only using a pair in the Pre slots of the ZMA currently. My first of six scenario's for this tube. Let me know...I will buy them from you...if you do not like them. I am using them with the KT66 Tung-Sols...that they mate well with.

An yes, 11 hours does not make for a complete take on them. But, hopefully after a 100 hours an comparing to the 6N23P back in......will see (hear).

6N1P showed up last night. Popped them out of the boxes, popped them into the ZMA input section without incident - I think I like them better than the Nationals - but haven't really given them a chance to stretch their legs, or try with the stock KT66.

I'm off all next week, so I'll have plenty of time to listen while Brianne is at work - I should know more next week now that I have my tube lineup in hand and burning in.

Super Cryo Voshod's I assume you got. Not the GL's.

http://www.cryoset.com/catalog/product_info.php?cPath=21_24&products_id=251&osCs...

Well, I'm off to Pine Tree Apple Orchard to get my pre-ordered Apple Pies in a snow storm!  I love winter!  NOT!

I just changed Siemens E88CC 4 tubes from Europe Ebay seller to Tube Museum seller. The tubes from Tube Museum provide more than 30% sonic improvement.  It is substantial improvement. But the price of tubes from Tube Museum is more expensive than general eBay sellers of 20%.  You pay for what you get. However the tubes from Europe are much better than stock tubes.

I ran my ZMA with the Gold Lion KT66 tubes all day and they settled in somewhat.  The bias dropped to about 56 ma and the sound seemed more "dense" than with the Tung-Sols and also louder.  I don't know if the increase in volume is more due to the 20%+ greater tube strength than anything else?  The transformers, despite the higher bias, actually seem to be running cooler with the GLs than with the TSs.

Has anyone tried a pair of these choices, in the Pre A12 an B12 of the ZMA?

Tungsram 6922 Platinum Grade 2 x 75. = $150
Ediswan CV2492/6922 Platinum Cryo 2 x 108. = $216.
Philips SQE88CC/6922 Platinum Grade 2 x 169. = $338.
Telefunken E88CC/6922 Platinum Grade 2 x 149. = $298.

I'm currently using a pair of Nationals in my A12 an B12 positions an enjoying the results with the stock Tung-Sol KT66's...Inverter tubes/stock 6N23P's....an 6N1P's stock in my CSP3.

I've got the Tube Rolling Bug....an "try an stop me".  ;D

This morning I switched the position of Siemens E88CC/6922's with the Telefunken E88CC/6922's. The Siemens are now in positions 11A and 11B and the Telefunkens are in positions 12A and 12B. The Telefunkens are now the dominant tube and seems I've left the best arrangement until last. This combination brings out the best in the Telefunkens and is very seductive.

The Nationals aren't doing much for me...but then, I've not tried any other configurations for two weeks due to the new El Camino speakers I'm testing out. I didn't want to muddy the water with tube changes on top of new speakers breaking in.

I have next week off, I'm hoping to get back to tube testing now that they should all have 100 or so hours on them or more.