haha,

is that an inexact category again?

A tube gain stage should be easy to make.... I just need to find a schematic.
But won't it add a layer of circuitry between the source and the amp? A new pair of pots, etc...
I just got a pair of pretty expensive atts!
Won't it blur the details in exchange of better dynamics? I never used a preamp, so please forgive the amateurism.

Yes to your first question, no to the second.  Indeed, with the ZStage there's another component and a pair of added cables involved, which, from a purist viewpoint, is not ideal.  But in return, you get boosted dynamics.  Decware's components are really transparent, so the ZStage should not pose much in terms of degradation relative to more common preamps.

You already ordered the attenuators and I would suggest (if you want the added benefits of increased dynamics), to replace the current volume pots on the M-T with them.  Then, you can plug in a ZStage (or CSP2+ if you need more inputs) in the signal path between the DAC and the M-T and get the best overall results.  Make sure to use short, good quality IC's.

If you can build your own ZStage-like version, that's even better, except make sure it ends up being really transparent, otherwise you run the risk of adding non-insignificant sonic degradation.

In the end, the attenuators can be useful at pinpointing the exact volume you want (both day and night sessions), and the ZStage will improve upon sound dynamics.  Best of both worlds, on top of already having installed those great VCaps.  

this is the analog output board of my DIY audionote dac (6922 tubes)I rewired the original pcb in point-to-point on a piece of crap-wood from the 1$ store
If I made the output of this dac variable, would that equate to a zstage? Or rather a zbox, because I couldn't push it higher than its maximum 2.5V. Is it necessary to go up to 5v in order to be able to 'ride the gain' on the MT?

audionote dac2.1 ptp par raduschkamuschka, sur Flickr

I am about to build a zstage, based on the kit4 schematic provided by Steve on the website. i assume this is the same concept as the finished product, minus the frontal switch and the 0c2 rectifier. I ordered parts from partsconnexion and I happen to have a lot of useful parts, including a great transformer that came with the zkit1. I have the auricaps he uses in the zstage, one stereo alps pot lying around, one great 6922, etc. I just do not understand where the solid core copper wire goes from the input rca's. It goes straight to the tube alright, but what does it do there? Shouldn't it rather go to the volume pot ground?

So, your about to build a preamp!  ;) do enjoy the process!

I guess theZBox will work too, absolutely:  The source is 2.5 V and the amp may go full power at 2 Volts or less, depending on the driver tube (1 Volt with the 12aT7).  In any case, there's a positive output voltage differential between the ZBox and amp, enough to boost dynamics riding the gain through the ZBox output control.  

In this case, the volume settings between the two components would be adjusted so that there's a positive voltage (gain) differential between the ZBox output and the amp's output.  In the case of a 12aT7 driver, this difference is a little less than 1.5 V and significantly less with the 12aU7 driver, although probably still enough.

Same principle, only in this case the extra gain of the ZStage (up to 5 Volts) is not required due to the excessive source output voltage and the amp's highish gain.  A simple passive preamp would work the same way, as would an output-controlled DAC.

Those brand new attenuators will play a role in better dialing-in (fine-tune) that volume level on the amp to precisely allow listenable volumes and at the same time improving the dynamics through the ZBox output control.