I'm sorry, I meant DM945's.

Well, I think it is the most important and relevant topic not yet covered in my learning curve so far.  It is amazing the little attention this topic has in this forum, considering.

Thanks for your input.

I understand that the amps are subjected to a quality control test prior to being shipped. This would probably include running each one for a while. The tubes are tested and packaged.

As far as the DM945's go I believe they have the same ribbon tweeter as my MG944's do. On the speakers, the tweeter might sound a little stiff at first, but they will wear in quickly and gradually smooth out over the first few sessions. I do recall my speakers improving steadily during the first couple of weeks.

From a prior post somebody else wrote on the MG944's

Shit, no bass, I mean nothing. I thought to myself "these high end guys don't like anything under 100hz." I then remembered that it takes a while for speakers to warm up, so I went and made supper.
When I came back, wow, what a difference. They sound great. It just took a little while to find the little monkeys that are in charge of pounding out the bass.

So I think that there is nothing to be concerned with about break-in.

In the near future, I'm also considering the possibility of further upgrading the system by adding a Z-Stage.  Reason being, my current DAC is pure SS, and although it sounds good, I'm interested in the triode signature that may be imparted to the analog signal before going to the M Torii.  

As you know, SS DACs tend to be on the analytical side, very clear but not too musical.  I'm also interested in improving system dynamics via the extra gain, as described in the Z-Stage brochure.

The combination of Music Streamer II + Z-Stage should be the best, as it will keep the accurate asynchronous sampling from the MSII but with the tube character of the Z-DAC, for example.

What do you think?  

Personally I'd wait until I had the speakers and amp and they're broken in before considering a ZStage or CSP2+ (I've had a different experience than Jim with my CSP2, but the truth is that you may not need any further components when you get the Mini-Torii and the speakers).

Don't overlook the magic that the tubed input stage of the Mini-Torii will deliver. And it may just highlight the strengths that your DAC has and make everything "just right."

I've encountered a very musical solid state DAC in the ZDAC-1 that unfortunately is not in production any longer. I have a great solid state DAC right now that doesn't need a tubed component between it and the amp. They're out there, yours may be one. I have a DAC and I had a ZBOX in use, and a CSP2 in use, and both at times in front of the Torii Mk III and finally decided they slow things down just a tad and I prefer the DAC straight into the Torii Mk III. So I suggest just keeping the idea of adding one of these way onto the back burner as you may be better served with better ICs, speaker cable, a power conditioner, etc. You'll be astonished at the sound you get when these are finally seasoned and may not need to make further moves for quite some time. Relax and wait for the adventure to begin.

I agree breakin on your speakers and amp will be a while, and they will change for the better in terms of warmth, texture, micro detail, punch etc. For me it is months, but you will likely get the main part out of the way with five to seven  5 hour on/5hr off  amp cycles with music, and I think the Esoteric breakin CD helps. Nice that it can be played when gone too. My MG944 and HR-1s got quite good in several days, notably better in several weeks, sounded pretty "right" in 2-3 months, and continue to improve over time.

Many tube amp folks like solid state DACs without tube stages, the amp literally being a tube stage. And adding a stage or pre depends a lot on your input stage, objectives and synergy. I have a ZSTAGE and agree, if your DAC is 2 volts or more, it may be good to get Steve to mod the ZSTAGE especially if you want to push it with higher output tubes since it is voiced for a 12AU7 and for 2 Volts or less input.

I don't quite get 2 or more volts output messing things up by a Zstage. I would think it would depend pretty much on how the DAC is voiced, and how your stage is tuned, cable etc...but I may be missing something. I like what the ZSTAGE does with my 2.2v-out Tranquility with  12AU7s, but I get distortion with my favorite 12AT7 tubes if I don't lower the software output which has its own sound that I do not prefer. My tastes anyway.

Also I use the ZSTAGE all the time with my Oppo and don't like having to change the cables. So I think I will get Steve to mod it for me when he and I get a chance...another input and switch, and raise the volts-in threshold. The Tranquility sounds great without it too so it is not that important to me, but I miss the tuning to the record thing from riding the gains...a very refined tool indeed. With my ZDAC running my computer and Oppo, I really felt like the ZSTAGE was a big upgrade.

Also, I don't think the ZSTAGE is the same as a CSP....more a tube stage with a little gain tweaking ability (5v), not a full blown pre. Very small and simple, very much a single tube stage with a very useful bias adjustment, and gain adjustment as icing on the tube stage cake. And you can really hear the tube you use like with a ZBOX, but riding the gain with the amp gain....the stage up, and amp down or visa versa, can be very useful for refining your sound experience overall and as compensation for recording quality irregularity....from your optimal settings, up the ZSTAGE for more tube sound, weight, punch, density, and down for more open lighter sound. Tuning recordings on the fly is very easy. The gain boost is a big plus too for DVD playback where the DVDs are mixed quiet.

And of course it will depend on everything in and out of the ZSTAGE, but once I got tubes and cables I liked, my ZSTAGE only helped, adding definitive breadth and flexibility to the quality of my inputs. The ZDAC and Tranquility sound great without the stage too though. So it makes sense to me to wait and see after you get used to your new gear too.

Edit: It is likely too that the qualities of a DAC's makeup and output sound characters may make the ZSTAGE a problem or benefit. A really good sounding DAC may or may not be best left to its own devices. I was hobbled with my exploration with the ZSTAGE/Tranquility do to the fact that most of my tubes are 12AT7s and they distorted with it. And it is possible that the refinement of the Tranquility's output is so refined in its focus on the many expressions of micro detail and how this plays into the ultimate presentation of an instrument, that a Stage could get in the way. After I get mine modded, I will know for my tastes anyway. I know it took some exploration for me to max out the refinement of sound on the ZSTAGE/ZDAC for my tastes, but it was worth it!

Thank you will, for a very informative analysis. You sure know your stuff.  I'm very new at this, but the topic fascinates me.

My point was (thinking ahead, as a future possible upgrade, not now), that if justified (depending on how my system performs after break-in), I wanted to consider the possibility of adding a ZStage to 'ride the gain' and improve dynamics, as well as neutralizing (tube-izing?) the existing, somewhat analytical, SS USB/DAC's output.  Best of both worlds.

But when I see that the Mini Torii has double sensitivity, vis á vis the majority of amps (1 V input for 100% power, instead of 2 Vs), and when considering the max output on my USB/DAC is 2.25 Vs, I envision ending up not being able to ride much before the volume becomes too loud. So, very little room for 'riding.'

IMHO this scenario is the opposite to what the Mini Torii and ZStage 'gain riding' combination work best at: Very low source/DAC output voltages, which allows the possibility of boosting the gain at input stages while controlling the overal volume through the amp, therefore creating headroom/dynamics potential.

It can still be done, though, it's just that it would probably require some mods to the ZStage to reduce the voltage range.  A compounding problem in my case is the USB/DAC has no volume control.  If I'm not mistaken, most of the time (depending on the source music dynamics), it will be running at 2 Vs +.  At this level, without a ZStage, the Mini runs 100% power at the mid volume point already.

Adding the ZStage at this point to 'ride the gain' would only allow adjusting it between zero and 2. As anything else above (3, 4 or 5) would force the Mini's volume to be at or near zero, not to clipp (100% power).

It would be different if I could control the USB/DAC's volume (i.e., output Vs). This way I could enact the typical iPod scenario of low input, allowing full 'riding the gain' manipulation for better headroom and sonics.

I'm probably all wrong at this, but so far is what I'm getting from this concept, that really intrigues me. I'm not familiar with the equipment (Tranquility, Oppo, etc.) you mention, so I'm not sure I get 100% what you are saying, although I get your general viewpoint.

IMHO, the Mini does not require any preamps,  I would like to exploit what theoretically the 'riding the gain' through a ZStage would do for it though.  If I'm way off here please help me learn.  Thanks for your assistance.