OK here is the assessment so far.
Here you have the Decware Signature Mono Blocks from many years back. These have a different input tube and a greatly modified power supply. Used them in single, two and three output tube modes pictured
Also the Integrated (original design from years back as well SS diode rectified) with and without the CSP2 preamp in place (pictured) My CSP as seen is housed in a Signature chassis but is I'm told electrically the same as the current production model minus the head phone jack and multi input features.
The Integrated has the CCE cap on the output tube sockets. This amp is now identical on all four channels running in what is "Zen" triode which has been on all the SV83/EL84 Decware amps. Running the outside or inside set of output tubes alone nets you approx. 3.5 watts from each EL34. The Mono Blocks are running JJ EL84s and single tube is about 1.5-1.8 watts and two tubes about 3.5 watts and three tube on up to about 5.5 watts.
All configs. fed signal by this iPhone 3Gs running Pandora radio streaming off a Belkin G/N wireless router on ATT DSL
Make fun of it as a source if so inclined but it is stupid good taken in the context of available online streaming media.
Sorry for bad pics. in a hurry
Room is a mess and that is a good thing for diffusion of reflected sound.
So unfortunately the Mono Blocks at higher volumes sound strained and not as dynamic even with 3 output tube installed. I will testify that Dan K had at DecFest a Zen kit 1 circuit board kit that he built a modified power supply for and it was stunningly powerful on the pair of MG944's at the Fest in Steve's big room. This effortlessness is not however what I experienced here at home with the Mono Blocks and even in three tube mode though the headroom was much improved the Mono Blocks, which were at one time a favorite of mine, just do not cut it anymore. The design of the power supply is not Decware and therefore these particular modified amps do not reflect Decware products in any way other than the circuit is a single ended triode design. That said lets move on to the exciting part.
The Integrated with the MG944's is just super holographic and simply musically a delight. Loads of slammin bass and just a room filling tapestry of detail and image that is head turning. With the CSP in the loop ahead of the amp the lush and fleshed out mid range is even more defined and the bass is just that bit more depth that you'd swear you were listening to way more than 3.5 wpc.
So will 3.5 watts drive the MG's? well this 3.5 watts I have here sure will. I can't say that the Mono Blocks did nothing better though. They had a bit more lower octave and that may well have been the straw that broke the power of these down at a more rapid rate. The Integrated that is now current production with tube rectification and about 6wpc and now comes with the CCE cap on the outputs is likely going to always sound amazing. With the MG944, the Radials and the two other sets of speakers I have here the CCE mod to the Lineup of Zen amps that take advantage of this plate/grid relationship is miraculous.
Ital as for the Bottlehead amp I'd say if you like the MG sound (try em) and the Bottlehead just won't do the job then speakers without a doubt are efficient enough to work with the numbers. Just the past few days though prove that synergy with the components is far more than just power.
I will be taking delivery of a Mini TORII next month and that should be yet another eye opener. As I said I saw/heard with my own eyes and ears a single Zen kit amp drive a pair of MG944's at Decware and the sound was killer. The kit probably had the 9800 ohm (Red) Decware output transformers. The Integrated has 3300 ohm (Blue) Decware OPTs but there again a different output tube and the relationship between all the parts has its effect.
The MG is a neutral and very balanced speaker which emphasizes nothing particular yet is fast and transparent with plenty of bass. The newer model than my pair has the plinth bases and the bottom octave are more predictable with that base. Bottom line is I just blew myself away with an iPhone and 3.5 watts of EL34 wired in triode and the MG's were in every way contributing to that picture. Only sat down for an hour and posted this message. It was immediately clear to me upon sitting down to listen that what an amp is capable of is not always the raw power factor but many other things like dynamics and detail. This turned into an amp review as well as speaker but it's the whole story. I'll be enjoying this amp and speaker combo thats for sure.