Zu Soul Supreme Recap -- Owners, what are your preferred system pairings with them?


I'll save a long backstory, but in short I've got the Zu Soul Supremes and I absolutely love them for what they do, at least in my relatively small (13x15x9) listening room.  I've had them a couple years as a follow-on to previous Zu speakers (Unions and Cubes, which I still own).  Those followed some vintage Altec horns (16 ohm Valencias and 19s)--which I love, but love the Zus more for daily listening.  Sean recommended the Supremes over the Druids at the time for the size of my listening room, although I suspect the Druids would have been as good or better regardless.

My interest is to hear from other Zu Soul Supreme owners...not may posts in this forum from owners that I can find.  I'd prefer to focus this discussion on the Soul Supremes, as there is a lot of great info already on the Druids and Definitions (which I assume are more prevalent in the wild), even though I'm sure have a ton of overlap in system synergy.

So...

What system components are you finding to be great/phenomenal matches to the Soul Supremes, what have you compared them to, and what hasn't worked as well?   Anyone running them with what you consider to be really high-end gear?  I'm super curious to see how far these speakers can go before a speaker upgrade makes way more sense.

Jay
128x128Ag insider logo xs@2xparsons

@cat_doorman could you share a picture of your shims. I’ve always found this concept confusing and I’ve never actually seen what they look like. 
 

thanks

I agree that the feet by themselves leave way too much gap, about 20mm (13/16”). I put cardboard shims between the floor and the bottom of the speaker to reduce the gap. Zu has a template in their DIY section, but it isn’t difficult to figure it out on your own. The gap under mine is about 8mm, but sometimes I second guess myself and use 2 shims instead of 3, opening the gap up to 12mm at least for a little bit. 

Cat - thanks for telling me about your experience - would be curious how big your gap is - always read too large a gap and your bass gets muddy, even disappears.

I have some Gaia footers that I have used on other speakers - yesterday I had set out to install these on the Supremes.  I have 100 year old wood floors so speakers are a little wobbly on the wood floors - knew the Gaia's wouldn't give me the recommended gap between speakers and floor but thought it might solve the wobble.  Even though there are three post options the Gaia's didn't fit on the Supremes so resorted to playing with gap and tweaking til I got a better foundation on the wood floors.  Still amazed this morning at how different the speakers sound with a 6 mm gap vs 3 mm.  Small change.  What are other Zu owners doing with feet and the gap on their speakers?

I know this thread is mostly about amplifiers so here is what I am using.

Right now have an LTA Ultralinear integrated playing with the Supremes. Great amp but until yesterday I thought it was bass and dynamics challenged.  Think I am re-evaluating that.

Also have nice combo of hot rodded Amp Camp monos and Don Sachs preamp.  Better dynamics but maybe not as much detail.  Plan to swap this combo in the new sounding Supremes in next day or so- curious as I thought dynamics were pretty good before tweaking the gap.

My wife smiles at me and sure she is thinking I have too much time on my hands...

 

 

 

@ladavid I played around with the gap quite a bit with the DW so I already had a pretty good idea where I wanted it when I upgraded to SS. Another surprising improvement was when I went to rubber feet on a platen. I don’t know if it was the decoupling or raising them a few inches off the floor. The gap with the feet is a little high for my taste, but that’s nothing a little cardboard couldn’t fix.

I have had my Soul Supremes about a year now.  One thing I have been disappointed with is that the speakers are not as dynamic as I had hoped.  I have not played with the floor gap til today - just put the speakers down when I received them - looking today it seems the gap was pretty minimal.  Maybe 3 mm.  Doubled the gap today so about 6 mm and amazed and how different these speakers sound.  There is a new lightness, sparkle and punch to the music.- should have played with the gap long ago!.  Heavy speakers to move around but play with the gap you will be surprised at how different just a little change makes.

I had an original set of Druids 10+ years ago - loved the sound of those speakers.  Have tried lots of others since but still good memories of the Druids.

I took advantage of the sale price on the Soul Supremes and should arrive in the new year.  They will replace Harbeth 30s - so very different speaker. 

I currently have a Hegel 390 amp so not sure how that is going to match with the Supremes in a fairly small room (12x13).  Have read S Casey's recommendation for power with his speakers but very few report on big power solid state amp with them - probably for a reason.  Love the functionality of the big Hegel - that would be tough to change but part of the adventure.. 

 

@mahughes Look for class A integrateds. The only SS amp I’ve used with DW and SS is the Schiit Aegir. Of course I used tubed preamps, Saga+ among others. I’m using the Aegir right now in fact. It’s only right after I switch back to my much more expensive tube amp that I find the Aegir lacking and then only by comparison. If you have the budget something like the Pass Int-25 would probably be great. 

I have Soul Superfly and want to move from endless boxes to an integrated. They apparently don’t mate well with SS but do people have examples of good SS matches? I’m otherwise looking at Decware or similar with a digital front end of Innuos/Chord.

It took a while, but my Soul Supremes came in. Haven’t dialed them in yet, but I already know I’m going to lose a lot of sleep. Is it contradictory to acknowledge the law of diminishing returns but still say they’re worth the upgrade? I just put them right where the Omen DW had been, but it already seems like there is just more there there, more immediacy, better definition, more separation, more depth to the soundstage. “The reason it’s a cliche is because it’s true.” So insert your favorite audiophile platitude here. They’re keepers. 


Used Druid Vs could be a great call too, but with the room size hifi-buck mentions, that seems like maybe a better fit for SS's?  I'm sure Gerrit & crew will have given you good advice on that, if you talked to him already.  My buddy had Druid 5s and I had the 6s, but both in slightly larger rooms.
I’d go with the used Druid V’s on the USAudio Mart.  I’ve owned them and they are pretty nice. I’ve also owned Def MKIV and preferred the Druids. I have not had a chance to hear the Soul Supremes however. 

I will be talking with Gerrit on Monday and will be leaning towards that direction. I figure that if I am going to upgrade from a speaker that I already love, might as well make it something really worth it, instead of buying the same speaker again. I am just amazed how much I love my Dirty Weekends, I am listening to them as I type this and they always put a smile on my face. But I know that I am always going to ask myself, "What if" if I don't go the Soul Supreme route. 
@hifi-buck

I sincerely don't think you will regret the move up to Soul Supremes.  I realize the price is a lot higher than DWs (which are great value speakers in their own right), but the SS are a special little speaker.  I still have mine in spite of 3 speaker upgrades since they were my main speakers.  I believe they are a special speaker in their line and remain so today in spite of newer speakers Zu have come out with.  About once a month I try to figure out where I could justify another system in my house built around the Soul Supremes.
“It’s better to regret something you have done, than to regret something you haven’t”

I finally pulled the trigger on Soul Supremes. Now I wait. I just have to find out for myself how much better they will be than the Omen DW. The one downside is that I’m already not getting enough sleep. Just one more album and then I’ll go to bed....
So 4 months has past since this, I ended up going with another pair of Dirty Weekends. High gloss red. But.....they went to do final assembly on them last week and noticed a flaw in the finish. So they have to start the finish process over again. Which is now about another month out. So I am again at a crossroads. I can have a pair of Soul Supreme's in about a week. And I keep gravitating that way. I just bought a new Hegel H390 amp for these speakers. Which will be amazing. I am already using it on my current Dirty Weekends. I want slam, I want live music sound, but I also want some refinement and that "audiophile" experience that I have got with my other speakers, which are Quad S-2's. I keep thinking that the Supreme is the way to go. But I do LOVE my current Dirty Weekends. The room size is small, so the Soul Supreme's might be right at home. 12X10 with 8 foot ceilings. They will be positioned about 7" off the side walls and the front baffle of the speaker about 30" from rear wall. No openings, controlled, can shut the door.
Can someone explain why the Supremes are says to mate wuth solid state or valves but the Superfly only with valves?
Post removed 
I mentioned that term in my case to explain why I made some of the "investment" decisions I made in my system.  You are thinking about the decisions correctly in your case in my opinion.  If you lived with a set of speakers for 20 years, well done--that means you really made a wise choice and got significant enjoyment from them, I presume.

I have a buddy with the DWs and he has them in a large room and they are quite good, but i think a slightly different sound than the Soul Supremes.  His room is a little boomy (2 story) and he plays them loud and that's what he was going for in that room I think.  The heart of the Zu sound will be similar between the two speakers, but I feel like the Soul Supremes, while they still rock, were intended to give a little more refined sound in a slightly more controlled environment (ie. smaller room, but not necessarily a "small" room).  I predict they are simply a little more capable.

As another comparison, I started my Zu trip with Unions, which I only sold recently to my cousin who loves them, and the Soul Supremes were a nice step up for me in the medium-sized room I had at the time.  I suspect the Unions to perform at similar levels to DWs.  I feel like the Soul Supremes enjoy a little side reflection to sound larger and more magical ...they feel a little smaller in the room I have them in now which doesn't have the side reflections.  Again, I think the Soul Supremes may need really strong placement to get their real performance, but when you do, it should be a good level or two above some of Zu's lower models.

Again, this is all my opinion, but in the right room conditions, the Soul Supremes are a VERY capable speaker that it would take a LOT of investment to make the weak link in a phenomenal system.  I feel that they are a sincere sweet spot in the very strong Zu lineup.
Thanks for the insight @parsons

Maybe I'm not old enough to think "end game" yet. Even though I've had my previous main speakers for 20 years, I never for a moment thought of them as my last. I also can't quite bring myself to get rid of them yet either. I guess a little sentimentality is to be expected sometimes. It feels strange to even think about trading in the Omen DW after having them for less than a year, but everything I've read about the Soul Supreme tells me there is another level of Zu I need to experience, even if it's only the next step. Though if I keep averaging 10 years per step I may run out of time before I get much further.
I'll try to answer why I kept the Soul Supremes over the Druid 6's (not 5's, as stated in the question--I never owned the 5s, but heard them a couple times)...but my answer will be unashamedly subjective in nature.  As scientific as I tried to make my personal comparisons, a bunch of things changed (including my rooms, and my exposure to field coil drivers) and I ultimately relied on emotion.  And by the way, the Soul Supremes are for the moment in a 3rd system I own, and are going to be moved to a 5th system.  So while I kept them, they have moved into a specialized spot for me personally....they continued to get trickled down to lesser-used systems.  But I still love them...I think.  But let me be clear--for the $, they remain a phenomenal speaker, especially at used prices.

Before I go there, however, while I understand Sean's comments that Zu's love high-power (I'm quoting the post, I don't remember specifically reading that, but I don't doubt he said it), that by itself probably explains where I feel like some of the design choices made at Zu might differ from goals of my own.

I'll just state my own bias...building a speaker that is by nature quite high (very high?) in efficiency (98-101db or whatever range they end up) and then having the feeling that they really need "high-power" seems like something was ultimately traded off that does not match my own personal design goals for a high-efficiency speaker.  I am not suggesting that everyone should end with flea watt SET amps, but I certainly do not personally feel that moving to "high-power" amps is an end-game answer for any high-efficiency, full range driver'd speaker.  The trade offs in capabilities as you move into the 50 wpc or higher amp designs are, by nature, trade offs that are easy to hear in transparent high-efficiency speakers.  Heck, even 18 wpc on 845 SET amps or a solid state SIT3 is easy to hear the trade-offs over something like 300B or PX4 and then again over 45 or 71a (when those amps have top designs and top parts).  You lose some micro detail and nuance, minimally, even if there is a gain on slam and dynamics.  Once you've heard a particular set of traits in those ranges, for a near-end-game emotional level, you'll find you need it all, not a trade-off one way or the other.  I have owned (and still own) a very large number of amps in many topologies, solid state and tubed, and have spent countless hours with each in many combos.  I'm not saying I know better than everyone--but I'm saying I have owned (and still own) about 10 different sets of high-efficiency speakers of different brands and eras, and about 30 amps to pair them all with.  And yes, much of this is trial and error and subjective preference, so if this paragraph has offended anyone, please don't be.  You may love "high power amps matched with Zus" and I won't challenge that for your personal situation.  It's just not what I found in the end (and ultimately moved on from the Zu design, in spite of still respecting it).

The Druid 6 is a much more capable speaker than the Soul Supreme...don't misread my action of keeping one and selling the other as a comparison in that respect.  Both are great speakers that have sweet spots for their usage and price ranges.  The Druid 6 took a larger step away from the Soul Supreme vs. the Druid 5 did, which given the 5's parts similarity to the Supremes, the Druid 5 may sit closer to the Supreme than the 6.  The 6 retrieved more detail, gave slightly better imaging, seemed to go a little lower, seemed to go a little higher, seemed to have slightly more black backgrounds, and more slam over the Supremes, all else "equal."  None of that should surprise people.  It was in my opinion more "high performance."  Zu probably feels like they accomplished what they had hoped to do with the 6...make a new speaker that was largely based on their experience to date but with everything just a little refined, better, newer, tighter.  It was "better" by the subjective (and probably objective) measuring posts.  However, I can't prove my next comments, but I also think they were more difficult to nail in terms of positioning and gear to get the most out of them.  They relied on a higher level of associated equipment (they could sound spectacularly average with the wrong gear and wrong room).  If you didn't have the right room or the ability to pull them out into the room, they sunk a bit in terms of soundstage.  I could say the same exact things about the Soul Supremes, but the range of their performance was tighter in those scenarios...it didn't get as crazy good so it also didn't have as far to drop when positioned incorrectly or paired with gear that was not as good as a match.

However, as good of a level as the 6s reached, I sold the 6s because they were not ever going to be end-game for me.  That was a very personal and subjective decision and not a knock on Zu or anyone who finds them to be "end game."  They are great speakers, and an improvement, but as you move into $10K and above speakers, the goal posts change for how amazing they need to be.

I kept the Soul Supremes because I love the look of them, they are capable of producing some very emotional and musical sound and seem to be a nice middle-ground from Zu between superb entry-level high-efficiency speakers that can be easy dropped into an environment and produce "fun" and what I suspect they intended to be more an "audiophile" speaker that tries to compete with the best.  The Supremes retrieve enough detail to make your ears perk up and go "wow" enough of the time when paired with great amps and source, but they don't try to compete with $20K or higher speakers.  For that reason I will probably continue to try to make a system around them to listen to on occasion.  They could certainly be the cornerstone of a very top end system, and if you got them for $2K you stole them at that price...well done.


So what brought me to this thread was my search for reviews and more info yon this speaker. I just ordered a pair and out down $2000 for them. I just want to know what I will be getting compared to what I’m already getting with the Dirty Weekends? Strictly two channel and no sub. Small room. 12x10 with 8!foot ceilings. Seems like a good fit for that room. 
I’m glad to see that my first post on this forum resurrected the Soul Supreme thread. Not a lot of threads out there on these speakers. I’m a big fan of ZU Audio. Have had my Dirty Weekends for nearly 3 years and have powered them with everything for low powered SET amps to high powered SS Monoblock amps that I am presently using. And in my experience, the more power, as long as it’s also quality power, the more they have responded and the better they sound. Straight from the man himself, Sean said that his ZU’s love high power. 
@parsons what was it that had you keep the Soul Supremes over the Druid V? My current room is a little bigger than yours 22x19x10avg but opens into other spaces so it feels bigger. I might move to a smaller more symmetric space that is easier to treat eventually. I’m planning to upgrade from the Omen DW during the 100% trade up period. I keep going back and forth between Omen Def, Soul Supreme, and I even saw some used Druid V listed, all at around the same price to make it more difficult.
Interested in what factored into your choice. I’m primarily using a Primaluna DPHP  
Since this thread is still going, I will throw out a couple of additional amps that are phenomenal pairings.

I got a hold of a custom 71a amp.  At 3/4 wpc it's sings way bigger and better than it should possibly be able to.  The tubes should be Cunninghams as I find them to sound the biggest and best.  I also found the 80 rectifier in my amp to make a giant difference in the sound...Cunningham was great there as well.

For an even bigger sound, and this is where I'm at in my main system now...a well designed PX4 amp.  The tubes are very hard to find, but I find them to be a little more neutral than top 300Bs, yet still giant sounding with all the benefits you want from tubes.  They are more nuanced and magical than 845s, all else equal.

The Decware SEPs and SETs are still quite good, but I would give the nod to the other tubes above with great iron and SET designs.
Yeah, I still own them in spite of having sold almost all my other Zus (including the Druid 6s I "replaced" them with).  They are great little speakers for their size and purpose and really respond well to amp changes.  In the right room (slightly smaller rooms) they are extremely musical, but in too large of a room they may struggle to sound massive.  They do benefit a lot from a good sub in my opinion.

I may sell them someday, but for now they are a nice reminder of why I was really into Zus and high-efficiency speakers...I learned a lot from them and they have greatly influenced my speaker choices today.
I am pairing my ZU Omen Mark 2 speakers  with upgraded drivers now 103 ...16 ohm .... they sound very good with my Kenwood KA 8100 integrated Amp.
I have rolled the tubes on the Melody a couple of times.  I'm running Elrogs in my Thoress monoblocks and they are the best tubes I've found for those amps, but they seemed to actually be slightly too aggressive in the Melody, oddly.  I got ahold of a new pair of PSVane WE Replica 845s and those are my faves between the 4-5 sets of 845s I own in this Melody amp.  Myself and others posted our thoughts on a number of these 845s in another a-gon thread if interested.  Agree, the Melody branded 845s are not awful, but can be improved upon IMHO.
Great read - thanks for your feedback on the various amps and combinations.  Nice to read the LTA plays in that league - although reported QC issues prevented me from ordering one.

Did you roll the tubes on the Melody? Pretty important as the stock ones stink.

Fyi- Definitions have a higher power requirement than Druids...


Big thumbs up for Nat Audio tube gear from Serbia, on my Zu Definitions 4 spkrs.
70W SE2SE 211s have replaced 35W Audion Black Shadow 845s, plus the Utopia tube pre.
Have never looked back.
I'm digging in on the Decware stuff.  I haven't read too many Zu owners with Decware that weren't very, very satisfied.  From the Decware side, it seems like Steve's design philosophy should align perfectly with Zus, so maybe it shouldn't be a surprise.
I have the Zu Audio "Soul" speakers not the supremes but I can say they pair very well with the three Decware Amps I have...Zen signature monoblocks at 2.3 wpc, Rachael at about 6 wpc, and the Torii MK IV at 20 wpc.  I like using a CSP3 preamp and more recently have added a ZROCK II to the mix...all Decware products.  Mark. 
Great question--one I actually thought of myself after I posted the update.

It's very, very solid directly from the Schiit Yggy (latest version).  If I'm honest, it's not giving much up, if anything.  Perhaps a tiny bit of breadth and depth in the sound stage--maybe just a little bit more flat in this regard, but not much, and certainly not "flat"--still massive.  It's dropped just the slightest bit of sparkle on cymbals.  I think the midrange is tending to fall just the slightest bit more centrally in the soundstage, which may be the same point I'm making from the first soundstage comments.  Decay is just the slightest bit reduced, which is lowering the live sound a tiny bit perhaps.

But I'm being very, very nitpicky here.  It still sounds phenomenal.  I can say I don't prefer it to having the MP-1 pre-amp in the mix, but I will say this...if I had access to some of my not-as-excellent preamps to put in to try, I suspect I would only prefer a pre-amp in the mix with the absolute best of them.  It's extremely solid as an integrated.  I would still probably say it's better than the Audions in my system, which is saying a TON.  YMMV.

Two additional data points...I have only heard the Audions and the Taboo III side-by-side with my Druid 6s, and I haven't yet heard the Taboo III with the Soul Supremes.  I won't get to for several more weeks as I'm in process of a long move to a new house.  So I'm only assuming it will have the same synergy with those speakers.

Also, the Taboo III did NOT blow my socks off with my 16 ohn Altec Valencias.  It was good, maybe even great, but not the level of synergy the Taboo seems to have with the Druid 6s.  In fact, I think I can say I still prefer the Melody 845 with the Valencias.
Since I would have wanted to see this list before I went on my amp quest (I'm still on it), I'll post my updated list...a year later from the last list.  

If anyone is driving Zu Druid 6s or Zu Soul Supremes, here is my prioritized/ranked list.  I would expect this list to be the same for Definition 4s or Druid 5s, although I don't own either of those two sets of speakers--but they share enough DNA with my 2 sets that I would predict their alignment.

Here’s my stack rank of amps to date, from best match-up to not-as-phenomenal:

1.  Decware Taboo III and Atma-Sphere MP-1 (HUGE surprise to me, but it's incredible)
2.  Audion Golden Dream I’s with upgraded caps, Atma-Sphere MP-1
3.  Thoress 845 monos, Atma-Sphere MP-1
4.  Linear Tube Audio MicroZOTL2, Atma-Sphere MP-1
5.  Linear Tube Audio MicroZOTL2, as integrated

-quality gap-

6.  Melody 845 integrated
7.  Primaluna Dialog Premium HP integrated with great preamp bypassing the PL pre-section, KT150s as output tubes--you can read my posts elsewhere on A-gon on my thoughts on this combo
8 tie.  Simaudio Moon i-7 integrated (bypassed with same great pre-amp)--very, very close second and best SS matchup--I was a little surprised this handled all aspects even slightly better than the SIT-2 below (perhaps I shouldn't be surprised since the current version of this amp is like $12K)--maybe the tiniest "etch" and maybe "brightness" on really the top end like trumpets and some female vocals that still probably puts this just barely in 2nd for me;  maybe also a slight bit more congestion in complicated passages;  shockingly good tube-like midrange for SS
8 tie. Simaudio Moon i-7 integrated (as integrated)--the pre-section in this is stellar, and to be honest, probably not distinguishable when used just as an amp with a really good pre-amp--hence maybe the best value of all I've owned?  Still just prefer the PL HP, however
10.  First Watt SIT-2 (with same great pre-amp)--very close to #s 7, 8s and 9, but a little too short on decay and "balls" at higher SPL--see my comparisons in other A-gon posts

-quality gap-

11.  PL Premium HP integrated with KT150s (as integrated)--very, very good, but I think the pre-amp section could be improved (maybe with a tube-roll?)

-quality gap-

12.  PL Premium HP integrated with KT120s (as integrated) -- upgrade to KT150s (better than 88s but not as good as 150s)
13.  PL Premium HP integrated with KT88s (as integrated) -- upgrade to KT150s (skip the 120s)
14.  McIntosh MHA100 Headphone Amp using it's speaker output--shockingly good--never tried it as just an amp, though--not sure I can bypass the pre-section
15 tie. Transcendent OTL Mini Beast with great pre-amp (would have liked a second to bridge and use as monoblocks--may try to find a second before I sell the first...might move up the list as mono’s)15 tie. Anthem P2 with great pre-amp
17.  Primaluna Premium Dialog 2 integrated with KT88s -- probably better if I bypassed it's pre-section but I haven't taken the time to run it that way since finding that combo on it's bigger brother, the HP
18.  Nelson Pass Amp Camp amp build--neat little solid state amp, but runs insanely hot and ultimately didn't do it for me
19.  Transcendent OTL SE--good but not as ballsy as it's bigger brother the Mini Beast
OK, so I bought a Melody AN845 and the MicroZotl pre-amp/1w amp with NOS tubes and the external power supply.  Both sound fantastic.  The MicroZotl as a pre with the Thoress 845 monos is superb--better than the MicroZotl as an intergrated, but I'm shocked at how good the MicroZotl is on it's own with just its 1w.  I'm going to roll some more tubes, then I'll put some thoughts together as to my new rankings.  The Atma-Sphere MP-1 is still in for its tune up...when back we can run some more pre and amp combos as well.
"Hey Parsons, tbh I think Soul Supremes and Druids should pair well with the same amps as they use the same drivers - Defs are a bit different as they are tougher to drive. I have heard a zillion amps with Zu, so this is my experience."

Yes, per Sean Casey, they use the same drivers and everything just different form and footprint (and price)

I bought a pair of Thoress 845 SET monos...very, very nice.  Waiting on some NOS replacement driver tubes before I declare full victory and move it to my #1 (to date), but they sound totally awesome with the mismatched ones that came with it already, so pretty sure it's a shoe-in, despite my long love affair with the Prima Luna/KT150s.

Would still like to try/hear direct comparisons to:

Atma-Sphere Novacrons
Atma-Sphere M60s
Audion Black Shadows
Decware SET (last_lemming, good call, read great things)
Linear Tube Audio ZOTL40 MKII
Melody AN845 (and compare to my Thoresses!)

I would also like to try a 300B SET (like the Audion Golden Nights)...but from reading alone, with my love of the KT150 tube characteristics over less powerful ones in that line (down to the EL34), I expect I might not enjoy the 300B as much as the 845.  I know that's controversial to some.  (That's why I said I'd like to hear one.)


I have the Omen Def mk2's with Radian upgrade. I use a Decware SET with a complement of Winged "C" tubes.  Very good tone, texture and bass. 
parsons - you might look at the Melody AN845 integrated. I forgot to list that one.


Great stuff, thank you both.

I'm coincidentally considering trying an 845 set amp.  Quad II Classics are also a great suggestion...will read up more on those.

I really want to love the First Watt stuff...someone has suggested I need to pair it with a really really good tube preamp rather than SS.  I tried it with an ARC LS-28...the pre had 100 hours on it and I think(?) was broken in, but still didn't totally sing for me with any of the 3 amps I tried.  I know a ton of people love them.  

As for the Sansui--totally awesome.  My Zu Cubes are in a third system with a Marantz 2365 and there are times where I want to listen to that combo more than some of my other stuff.
I'll chime in, as I own Superflys.  I was using FirstWatt amps for a few years (F3/M2), but I'm using a vintage Sansui AU-666 now.  I'm doing a very un-audiophile thing... I bumped up the floor gap on the Superflys to about an inch and I leave the loudness button on at all volume levels.  

Talk about a party... you get the Fender stack dynamics that Zu talks about in their marketing spiel and great tone from the vintage amp.  Bass does not sound bloated at all, it sounds like a decent subwoofer is in the system.  Clarity and resolution is a step down from the FW amps but to my ears the tradeoff is worth it.
Hey Parsons, tbh I think Soul Supremes and Druids should pair well with the same amps as they use the same drivers - Defs are a bit different as they are tougher to drive. I have heard a zillion amps with Zu, so this is my experience.

For SS:
FirstWatt F7 - I've had the SIT-1 and SIT-2 in my system, but just heard the F7 and thought it was great at the LA Audio Show. I think the rumors are this is the best FW amp now
Valvet class A monos
McIntosh - all of them are good, though the quad balanced amps are best
DarTZeel - a lot of scratch though

For Tube:
Quad ii Classics (which would probably be my choice)
845-based amps such as Audion, Sophia Electric, etc.
Mastersound SEP EL34 integrated 

I am not a 300B fan, so can't help in that direction. With Zu, I tended to prefer P/P over SET but that's personal preference. I generally don't like SET bass.

I'll start with my amp findings to date.

From best match found so far (top) to good match (bottom):

1) Primaluna Dialog Premium HP integrated with great preamp bypassing the PL pre-section, KT150s as output tubes--you can read my posts elsewhere on A-gon on my thoughts on this combo
2 tie) Simaudio Moon i-7 integrated (bypassed with same great pre-amp)--very, very close second and best SS matchup--I was a little surprised this handled all aspects even slightly better than the SIT-2 below (perhaps I shouldn't be surprised since the current version of this amp is like $12K)--maybe the tiniest "etch" and maybe "brightness" on really the top end like trumpets and some female vocals that still probably puts this just barely in 2nd for me;  maybe also a slight bit more congestion in complicated passages;  shockingly good tube-like midrange for SS
2 tie) Simaudio Moon i-7 integrated (as integrated)--the pre-section in this is stellar, and to be honest, probably not distinguishable when used just as an amp with a really good pre-amp--hence maybe the best value of all I've owned?  Still just prefer the PL HP, however
4) First Watt SIT-2 (with same great pre-amp)--very close to #s 1, 2 and 3, but a little too short on decay and "balls" at higher SPL--see my comparisons in other A-gon posts

-quality gap-

5) PL Premium HP integrated with KT150s (as integrated)--very, very good, but I think the pre-amp section could be improved (maybe with a tube-roll?)

-quality gap-

6) PL Premium HP integrated with KT120s (as integrated) -- upgrade to KT150s (better than 88s but not as good as 150s)
7) PL Premium HP integrated with KT88s (as integrated) -- upgrade to KT150s (skip the 120s)
8) McIntosh MHA100 Headphone Amp using it's speaker output--shockingly good--never tried it as just an amp, though--not sure I can bypass the pre-section
9) Transcendent OTL Mini Beast with great pre-amp (would have liked a second to bridge and use as monoblocks--may try to find a second before I sell the first...might move up the list as mono's)
10) Primaluna Premium Dialog 2 integrated with KT88s -- probably better if I bypassed it's pre-section but I haven't taken the time to run it that way since finding that combo on it's bigger brother, the HP
11) Nelson Pass Amp Camp amp build--neat little solid state amp, but runs insanely hot and ultimately didn't do it for me
12) Transcendent OTL SE--good but not as ballsy as it's bigger brother the Mini Beast

OK, that's a quick, unscientific run down based on my system, my room, the amps I own and have access to, and my opinion only.  In short, I could easily live and love the top 4 combos, but ultimately choose the tube solution with a great SS pre-amp over the two top solid states, which both had slight long-term downsides for me (the slightest listener fatigue on the SimAudio and the slightest lack of decay on the SIT-2).  I'm being VERY picky here, and feel fortunate to be able to own so many great amps that I can move around.

To note, I'm using a Truth solid state pre-amp from Ed Shilling of the Horn Shoppe--will post my pre-amp comparisons later here.  Also, the addition of a phenomenal headphone section makes #1 PL/Truth the clear winner for me.

For now.  There's 3-4 amps I'd love to hear but haven't had the chance that I suspect will give the top ones here a run on these speakers, but at a cost.