PrimaLuna Dialogue Preamp = emotionless?


After years of running a PS Audio Direcstream dac directly into ATC active floorstanders, I decided to take everyone’s advice and add a preamp into the mix. I picked up a used PrimaLuna Dialogue with highly regarded Mullard CV4003’s and Phillips 5R4GYS’s, the tubes purchased by the original owner five years ago from Upscale Audio, a terrific source. My correspondents were correct about adding a good preamp: it transforms everything in a very big way. That’s the good news -- and bad. The latter is the reason for posting.

Before the preamp, this was a modestly warm system, for which the Directstream is known. It was one in which it was not hard to find myself drawn into the music and performance. Since adding the PrimaLuna however, I find myself watching -- or listening to -- emotion but not feeling a thing. That is, beyond marveling at the other characteristics of the presentation. After that, I’m left perfectly cold - 100%. This is not at all what I expected -- or desire.

So what to do... Is there anything I should look at with the preamp? What about other preamps, preferably tube ones? The skinny these days is that tube gear developers are trying to imitate the "neutrality" of solid state, the so-called modern tube sound some call it. With the PrimaLuna, I was expecting to find a point in between the classic tube sound and the common solid state one, but what I’m hearing is more than a little distant from that.

(Other than adding the PrimaLuna and not having Ultimate beeswax fuses in the DS and PL currently for other reasons, nothing else in my system has changed: modified Oppo 203 w/ digital output only, PS Audio P15 Regenerator and AC-12 power cords, and MG Audio Design AG2 ICs,)
highstream
As you might suspect (or not) the choice of tubes in any amp or pre-amp can easily affect the sound you get. Just 'cause some one else liked, and some one else recommended, any particular tube really means nothing other than that they like them (in preference to what?). Add to that that the tubes are now 5 years old, and presumably tired from use, adds to the difficulty in assessing the benefits of using a (this) tubed pre-amp. If that isn't enough already, integration of the source with the pre-amp and the pre-amp with the speakers amp adds more to the equation.

Now if I had to guess what a likely problem may be for you is the interface of your pre-amp with your amp. The pre-amp has a fairly high output impedence and would only work best with an amp with a high input impedence (like X10 of the pre-amps output impedence).

Put your research hat on or wait for a good techie like Almarg to sign in.
I think your first move should be to roll in some new tubes. The current tube selection may not be to your taste or they need to be replaced; they are five years old with unknown history.

I don’t know the different tube stages of your amp, but you don’t need to use the same tubes in all positions.
I love the CV4003’s, but they are laid-back and you may need to add more dynamic and engaging tubes. NOS Amperex, Telefunken, Sylvania all have more detail, are very open, yet still retain the timbre of tubes. NOS tubes have more realistic sonics than new production and are worth the extra money. There are so many NOS you can try that are less expensive than those mentioned.

A good source of information..
http://www.audiotubes.com/12au7.htm

The rectifier tubes may also need replacing. And it's possible that a different brand may be more engaging, although Philips makes  excellent tubes.

Thanks for the replies. The preamp is non-demanding on tubes, so five years should be well within their range, although admittedly I don't know how the previous owner handled it (tubes were not why the previous owner sold it). In describing the Mullards, I found that many people use some version of warm, sweet, lush, liquid, smooth to, so that’s what I was expecting. I haven’t found this set of tubes laid back or lacking in dynamics. In anticipation of the PrimaLuna, I’ve started watching for good deals on Brimar CV4003’s and have just now rolled in an NOS pair. There’s also a pair of Brimar 13D5’s (CV4003) on the way. These four will cover the most important spots on the front end. The Brimars seem to be considered a bit warmer and more extended on top and bottom than the Mullards, but as you all say it’s in the mix (and taste).

Output impedance of the PL preamp is 256 ohms. Input impedance of the ATC SCM19As is 10K. I hadn’t considered that, although in a discussion with Don Sachs, he mentioned his preamp would need a 3uF cap to handle impedance that low (don’t know the output impedance of his).

P.S. Not sure why "follow" isn’t alerting me for this thread.
I'll try to keep this short and hope this isnt offensive. I bought a little cheap Bruce Moore Preamp from a guy that had a Dialogue being shipped to him but it hadn't come in yet. He contacted me and regretted selling me the preamp and wanted it back. He describes the same thing you said. He had 4 very nice amps solid state and tube on hand and just couldn't enjoy the amp like he was hoping. He bought many highly regarded NOS tubes ( spent a lot of money) but couldn't get it to work even after 8 months, we still stay in touch and he is going to sell the amp. 
I love the Brimar CV4003's, I'm using them in one of my amps.
I previously used Mullard longplate square getters. The Brimar has a more extended top-end than Mullard with more transparency, yet keeps a nice amount of warmth. I always use Brimar in one of the stages of my amps.
There still may be the possibility that using a neutral tube in one of the stages may present more engaging sonics, but I'm interested in your findings.

The preamp output impedance of 256 ohms is a good match in your situation and shouldn't present any issues with SS or tube amps.


Have you swapped the PL out for Directstream DAC recently? This is what I would do before spending any money. You might find as I did that adding a tube preamp between DAC and amp was a matter of tradeoffs. 

After reading the @paulcreed comments, trying different rectification may help influence the speed and impact of the PL.

@helomech - I don't understand your suggestion. As indicated in the OP, I ran from the Directstream to the speakers directly before adding the preamp. Hence the comment on how much of an improvement the latter was in all ways but one.

I got a reply from PL NA today that says the Mullards should be warm, and suggested changing the input tubes and, failing improvement there, take a photo of the bottom insides to see if any modification had been made.

The first pair of Brimar CV4003's, inserted in the center slots (6 in total, 3 each side), are having the same effects I've seen many times with a new cable. That is, the sound is warmer but lacks clarity and dynamics and is a bit recessed spatially. Have to see what develops with burn in. 
Of course, maybe it's the Philips rectifiers that have seen their day. They should be warm too. I had a similar problem with the stock rectifier that came with my Lampi Atlantic TRP dac (currently being repaired). After trying a few others, I found an Osram U50 that gave the dac more warmth and a whole lot more. 
highstream...If what you mean by ’emotionless’... the music not pulling you into the performance...I would have to disagree with your findings. My PL is a music making machine that brings out the best that the the DS dac has to offer. I have tried many different tube types...and for my likes... the Amperex NOS 7316 is a great tube for revealing the best of what the the PL has to offer. For the recifiers, I like the Brimar NOS 5R4GY. They are a bit more musically involving than the Phillips,which can sound a bit to dry for my liking.

Also..the 7316 foil d getter [1958] is a killer tube that I use in the center slots. It brings/adds a touch more humanity to the table... 8)
The published 256 ohm output impedance is most probably measured at 1KHz and can be (and most likely is) much higher as the frequency response varies during actual music playback. A 10K input impedance is lower than average for a solid state amplifier and is probably a better match when paired with the (solid state) PS Audio component.      
less is more in the idea of electronics in the audio chain.

If one had a very satisfying sound quality with active speakers, before a preamp was added in..and then had ’perceptively’ worse sound quality after a preamp was added in, then..get rid of the preamp, and go back to being without a preamp.

I’ve had my hands inside of and torn down and modified some good 50 preamplifiers of all brands and quality levels, besides rebuilds of preamps for others. mostly done with single cause analysis in the chain of modification(s) done in each unit.

The conclusion is that if the load of the source as compared to the input of the amplifying device..if this pair is well matched..then.. the addition of an active preamp will likely be degrading. Ok, will inescapably be degrading.

Even a single piece of wire is degrading to sound quality. So a box of active and passive components, that the internal and overall distorting and signal changing/damaging interactions count into the hundreds...

..where this 100+ interactions device, is called a preamp..that if this device is added in, then the simple logic is that --- it degrades.

It’s supposed one single advantage is that it is supposed to better match impedance between source and input/load, and if that part is taken care of already..then the preamp is a clear cut degradation to the given optimized system.

in 35 years of playing with audio gear re my hands inside of it and making rebuilding, doing it all as single cause analysis down to single resistor changes and the like...this... informs me that preamps are almost always a degradation to the sound quality of an audio system. that their advantages are limited.

Where logically, by all possible methods of analysis..that a complex device like a preamplifier is 100% a source of signal degradation, and one must try and decide if that degradation is outweighed by the single benefit of better signal impedance matching (cables must be added into this calculation) to the input circuit of the amplifying device.

I know it would be best for me to encourage you to buy more cables as we make and sell cables, but in audio ’less is more’, and that --- is inescapable. It is due to how signal itself interacts with conductive materials, dielectrics, transistors, and so on.

Re the subject of fundamental single cause analysis..when one goes completely to ground in the most fundamental way possible, at the primary divide.. in the realm of electricity being the carrier for/of signal at the molecular interactive...We designed and built and sell the liquid metal cables and they are utterly unique in the realm of signal conductors of all kinds (in the world), being fully liquid at room temperature, and requiring the application of complex math surrounding Quantum Electrodynamics (QED) and higher level math electrokinetics to analyze.... and this math and science is unsolved at this time.

Basically put, people get a chance to hear what wire sounds like for the first time in their lives (collectively and individually), like a fish that experiences the difference of ’other’ (outside of water) for the first time ever.

This is difficult or impossible to do in audio, due to the generally hundreds of interactions in an entire system, that are all conflated - inside chains or series of black boxes. So we presented to all... for the first time in audio, period, the essential single fundamental -- as a difference. It is actually a really big deal, for those who think it through.

There is a lot of detail and points I’m leaving out of my argument (preamps and the idea of fundamental single cause analysis in the complex chain of audio), re things people will hold up to question, but think of them as being there, but unspoken.... as I’m not going to write a thesis or book chapter on it..
teo audio,
Well...I guess either one likes a preamp in the chain...or they don't. Most people I think prefer a pre for their home audio music making enjoyment...not to mention the switching capabilities. As always...ymmv 
"...if this pair is well matched..then.. the addition of an active preamp will likely be degrading. Ok, will inescapably be degrading."

I have nowhere near the hands-on experience you have to disagree with this statement but I think this is true if measured performance is the only yardstick used for making the comparison. The actual listening experience may or may not always agree with this assertion. The end-to-end synergy among all the components from source to speakers, including all the cables in between create an audio "ecosystem" that is somewhat unpredictable when measurements are more locally optimized. This could include certain elements such as added colorations which can make a system "sound" fantastic but measure poorly given the parameters used in those measurements. My 2 cents.
@ aolmrd124   I'm afraid you missed the jist of the OP and discussion. I didn't say the PL is emotionless, but that contrary to expectations the one I'm listening to is and wondered if I was missing something, along with asking about alternatives (in case this one doesn't work out). Thanks for the suggestions about tubes. I have listened to the NOS Brimar 5Z4G rectifier, a different tube, in a Lampi Atlantic TRP dac. I found it euphonic and very good all around, but had this sense that it was sedating rather than enchanting me. It turned out I wasn't alone in that thought. Certainly not all Brimar tubes sound the same, to wit the CV4003 I've added, although warmth seems to be part of Brimar's makeup, if user and dealer comments are to be believed. Any thoughts about how the 5RGY would be different than the 5Z4G?

@teo  I don't know what to say except that if you read what my OP to say that I found the PL addition worse, you missed it by a long shot. I said that it was a great addition, really a fantastic addition, in all respects but one, and I posted here to get help figuring out about that one. Speaking generally, of the roughly 10-15 preamp developers, same-dac users and others that have offered advice about adding a preamp, only two, including yourself, have argued against it. Even Paul McGowen of PS Audio, after decades of believing that a direct dac to amp connection is best -- it's even in the Directstream manual! -- has in the past week or two admitted on his blog that he's been wrong all this time, after finally doing some comparison testing with one good preamp or another. So yes, I know it's counterintuitive, contrary to a belief I had been operating on for several years out of keeping it simple and logic, but then so is a lot in audio.
Sorry high stream...after re-reading your post... I now see what you were saying.
Never listened to the 5Z4G so I can not comment.
Thanks for the suggestions. Twenty-five hours in, the Brimar CV4003’s have improved a lot but like the Brimar rectifier I mentioned, have turned the preamp into sounding pleasant, which is not a recommendation. Maybe a matter of placement? Have to play around and wait awhile as they burn in. The Amperex 7316s don’t come cheap. From what I’ve been able to find, the aura around D-Getters has more to do with that characteristic happening to be in tubes people have liked, rather than the type of getter having something specifically to do with it. The Brimar rectifier sell for a lot less, so will give it a try. The PL tech suggested the PL 5AR4, which I have, or what some customers have liked, the JJ GZ-34.

I’m going to re-verify that 10K ATC amp impedance, as a few people have commented about it seeming unusually low.
Actually, on second look, the Brimar recti doesn’t sell for a lot less. I’ve seen a pair for as much as $699, although most are in the $130 each range + shipping from the UK.
The 7316 with the foil strip getters are a long plate design. To my ears... they are much more lush/organic sounding with great bass slam... than the large/small O getter short plates that followed after the 1958 foil type.
  The 7316 tubes are also a very,very quiet 12au7... which is a great bonus for the lowering of the preamps noise floor. They also come in a D-stirrup-shaped getter that should not be confused with the foil one. Some folks will try to pass them as the original foil design [because of the d-shaped getter] so beware of that when shopping around...
highstream,

I use a Dialogue Premium (DP) preamp and have the following FWIW comments. I run McCormack amplification and Thiel CS5's.

After a while the DP seemed analytical to me and I considered selling it. This was with Phillips rectifiers and after several tube changes. I like Seimens and Mazdas the best. Regardless of the tubes, the DP seems to me to focus on the vocals in the mix. 

I also run a Conrad Johnson 17LS2, which has a warmer sound than the DP and it seems more nuanced and textured. It has more PRAT to me but not quite as much bass slam.

I also use an Axiom II with Walker mods passive preamp and it provides the most revealing sound - it seems to provide the best presence but bad recordings can be rough on the ears.

The interesting thing is how my front end impacted the preamp sound. First I replaced a Ric Schultz modifed Oppo 103 with an AudioSpace CD8 used as a transport and a Theta ProBasic III DAC. I then kept the DAC and moved to a PS Audio PerfectWave transport. This last change was a real wow moment as I heard a lot more detail and the live presence improved for all three preamps, but especially for the DP. The DP's PRAT improved as well.

I just switched to 10 gauge from 16 gauge copper multi-strand speaker and this also provided more detail and better decay, which, to me, again added more presence.

Again, FWIW.

Thanks for listening,

Dsper
I added a Ayre KX-5 to my PS DS Dac. Matches well and adds the depth and feeling I think you are missing.

ozzy
15 or so years ago I sold my Preamp and bought a BAT VK5i SE it came with new production RCA 6922's and couldn't enjoy the preamp. The amp took 8 6922's. I knew it was the tubes so I bought 8 bugle boys it was better but the music didn't grab me. Was advised to buy nos power supply tubes so I did. Music just wasn't as fun listening to music anymore. I figured I needed to warm things up so I bought some nice nos Valvo's and then Mullards, everybody said BAT was so nice. I sold the amp. Funny thing was while I was chasing tubes to fix the BAT I listened to my 10 pound Don Allen Preamp that came with some kind of oddball $15 tubes he chose for building the preamp that was a complete joy to listen to big tight bass wonderful detail reteaveal but main thing it was very musical. I saw a video of Kevin Deal talking what makes the prima Luna so great was how much it weighed and how many parts are in it and a bad sounding preamps are light with not many parts in it. I don't know if I agree with that one. Problem is with all the things involved in a system a few things can through it off. You don't know if you can fix it unless you try but it can be expensive and agrivating road just to listen to music.
I’m not a PL owner but have owned many tube preamps. I highly recommend NOS Tung Sol rectifiers for a deep bottom end.

For a dynamic, lively presentation 1950s Amperex Holland Bugle Boys are an affordable alternative to the 7316 tube.


@paulcreed
I had a BAT BAT VK5i a long time ago, with a similar experience - based on reputation I thought I was in for an amazing preamp listening experience, but it definitely was NOT a joy to listen to. Tried tube rolling, including Tung-Sol 5881, etc. At best, maintaining all those tubes and keeping noise low was a nightmare. That said, my system was a mess back then with a lot of problems - but I certainly wouldn’t ever give the VK5i another try.

But all else being equal (and it never is), I do believe weight (meaningful weight) and parts quality are at least somewhat correlated to sound quality. I definitely don’t see anything wrong with Kevin’s PrimaLuna pitch on that front.
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Highstream 12-5-2019
... failing improvement there, take a photo of the bottom insides to see if any modification had been made.

It would probably be a good idea to take a look at the underside of the unit in any case, especially to verify that the two output coupling capacitors are the same as the two white objects that are shown closest to the output jacks in this photo, which appears on PL’s website page for the Dialogue Premium preamp as currently produced.

Those objects appear to be 10 uF (ten microfarad) Mundorf capacitors. But it seems possible that in the 5+ years since your unit was produced the output coupling capacitors that are being used have been changed. If those are what is in your unit, though, and assuming the rest of the design of the output stage is the same as in the currently produced version of the Dialogue Premium (with a nominal output impedance of 256 ohms), the output impedance of your unit at the worst case audible frequency (20 Hz) will be about 836 ohms, which means it should be suitable for driving the 10K input impedance of the active speakers.

@newbee, thanks for the mention early in the thread. I just noticed the thread now.

The point @kalali made earlier, that ...

The published 256 ohm output impedance is most probably measured at 1KHz and can be (and most likely is) much higher as the frequency response varies during actual music playback.

... is absolutely correct, especially in the case of many tube-based preamps. With the highest output impedance within the audible range usually being at 20 Hz.

Regards,
-- Al
highsream, but being emotionless, am assuming you want more of that CJ warmth from the earlier CJ gear. If so you will need to make two changes.

1. replace the stock coupling caps with jensen or Jupiter copper foil,
2. replace the rectifier tubes with PSVANE 274 high fi grades. the PL pre will come to life then. Its very well made and uses dual mono power supply throughout.

would also suggest you swap out your DAC for a Denafrips. Even the cheapest version will out perform your current dac.

best
Simple solution. The OP just hasn’t found the good preamp for his tastes.
What he is seeking is ENERGY in the sound, along to go with the euphonia that the PL is giving him. The PL is just not the one.
Preamps with energy I know of:
Naim, Simaudio Moon.


An interesting item of note is TIMING. When I use my DAC>amp pathway in the system, there is a purity, openness and (maybe most importantly) a cohesive-timing aspect that is a big plus... When using my $$$ preamp, all sorts of ‘audiophile’ aspects, like bass, textures, width, depth, separation, in room presence, all get “better.” BUT that simpler signal path of open flowing music all tied together, with seemingly slightly better timing, is way easier to connect to the musical intent of the musician. It might not have all the fullness and tone of the pre but my mind doesn’t care... until I’m ready switch to the pre for a week or two. 
My take on "emotionless" is different than johnss. 
being emotionless, am assuming you want more of that CJ warmth from the earlier CJ gear.

If you are looking for warmth, then keep the Mullards and use rectifiers that are more lively and provide more clarity. A change in coupling caps could also help.
I assumed you needed a more engaging experience; more dynamic, more transparent and 3 dimensional. It's easy to have these characteristics and maintain some warmth.
 I still maintain it's a mistake to use the same style of tube throughout all the stages. 

Can you provide a more precise description of the sonics you seek from your system?

johnss said....”would also suggest you swap out your DAC for a Denafrips. Even the cheapest version will out perform your current dac”

Hmmm....would you have first hand knowledge of this or are you relying on reviews and speculation?
first hand experience. bought their cheapest dac; around 660-690.... won't mention any names but compared it to dacs in 2k to 3k range. the little denafrips was much more organic sounding, better imaging, better sound stage depth. so took the plunge and also bought the next model up, called Pontus. did everything the smaller DAC did only better. 
So...you also compared the Denafrips directly to highstreams current PSA DS dac with the latest Windom firmware?
Look you really do not know what you have
You have a  incredible preamp,,
the problem = no life/murky/not happy with resolution/etc etc 
Easy fix, 
Count youtself very lucky,,here is the easy simple fix.
You  have SIX AU plugs. 
Do what i did to mkae my defy7 to come to life, 
add the 
Philips Special Quality E80CC , ~~aka, tall Boys to all 6 AU spots. 
Then report back to us. btw also look at the Siemens tall Boys, look identical to the Philips,,
btw, from hench forth the Philips SQE80CC will be known as PSQE80CC. , as i am telling the world about this tube, and prices are about to sky rocket.  I plan to add the Cayin SC6 which has 4 AU's in the pre
Make sure you posta  report on the PSQ's, as i want confirmation on what i  know to be true, no hype. 
So dump all your NOS, cheap on ebay,  and buy the PSQ. 
Hi All,

First I replaced a Ric Schultz modifed Oppo 103
I did not want to say anything earlier but some of the other posts have emboldened me.

When I started looking at DACs and auditioning them in my system -  Hegel, Rega, Benchmark, Naim, PS Audio - they all sounded more alive. The Oppo, in comparison, was much more tame and bland.

System synergy is everything and maybe the Dialogue Premium and the Oppo just do not get along together.

Thanks for listening,

Dsper


Toss out a problem like this and get a myriad of ideas! Thanks.

I've now done are couple of things. First, I got ahold of a two of pairs of Brimar CV4003 tubes, one pair being the highly regarded 13D5 version, and placed them in the four key 12AU7 locations. That's done wonders in terms of cutting the cool edge and enhancing the quality of sound all around.  

The second thing I did was consider getting another, somewhat better preamp in a similar price range to the used PL. It's something I would have done from the beginning had I been aware of the options. Specifically, I looked most closely at the well-regarded Don Sachs 6SN7 and the Supratek Chardonnay (Australia), which is designed around the same tube. After asking for advice at What's Best forum, doing a lot of reading, exchanging PM's and asking questions of the developers -- both are one man operations -- I decided on the Supratek. Among the reasons that most favored it for me is that it is explicitly advertised as naturally warm, and that it has true balanced outputs, which should solve the noise problem with the Lampi dac (when it comes back). I don't think the Sachs' unbalanced pre would have done that, and he seemed inclined to agree. I should be seeing it in two to three months. In the meantime, the PL has taken a very nice turn. 

@Dsper  The Oppo's analog board was removed, so it's no longer a dac, if that's what you are referring to. Ric improved the digital circuitry, which is almost identical to the 205's, replaced the power supply, better stabilized the disc player and got rid of the optical port, which he said undermined the unit's sound. In addition, between Oppo and dac are a PAD Neptune spdif cable and an iFi spdif iPurifier, the latter powered by a Paul Hynes SR4 LPS with a Zenwave Audio copper (5V) power line. The Oppo also has the advantage of allowing very good audio and video in one unit, which these days is an exception.
After years of running a PS Audio Direcstream dac
Sorry, did not read the first line in your post!
Wow I didn’t realize the PrimaLuna preamp uses such a large heap of 12AU7. I’ve had 3 or 4 amps & preamps that use these tubes, and every time the 12AU7 has ended up seeming like the major bottleneck in system performance. I tried some of the NOS 12AU7 and 5814 to solve the problem, but only got so far - still sounded like the "12AU7 bottleneck". Then I used the 12BH7 sub whenever there was enough heater current overhead available to supply them (they are a drop-in sub otherwise) - and the result was always a much more dynamic, engaging, "alive" sound. 13D5 has been pitched as an excellent sub too, and (I think) has the huge advantage (versus 12BH7) of not drawing extra heater current (which you’ll probably need for your application) though I’ve not personally tried them.

I’d recommend not burning more money chasing NOS 12AU7, and try some of these sub types which are simply superior sounding to 12AU7.

The E80CC recommended above also look cool, and don’t draw extra heater current either. I think anyone who’s spent time looking for 12AU7 alternatives has realized how much the 12AU7 actually sucks.
test from support.
mulveling  said..." I think anyone who’s spent time looking for 12AU7 alternatives has realized how much the 12AU7 actually sucks.’

Your blanket statement of 12au7’s sucking is just that...a personal opinion at best. We all listen differently and what I like,may not be..what you like. Which is completely fine. As they say..horses for courses.
PS audio’s voicing tends to be on the warm side and was a good complement to the ATCs "surgical" sound.
Introducing a tube preamp does not necessarily mean that it will sound warm but rather sound more transparent with midrange bloom / forwardness, depending on the tube and the voicing of the preamp.
In other words a miss-match with your speakers.

Does the preamp add other value that you didn’t have before- example better dynamics and drive? If so, there are things you can do. If not then you are barking up the wrong tree.

If there is added value in other areas you can alter the sound to make it more warm,
The RCA 5963 variant of the 12AU7 will definitely sound warm and smooth.
Cabling could be another area- definitely ditch any cables with silver plating for example. I assume that your preamp does not have balanced connections and that your speakers do, so you must be using some adaptors.
While not necessarily bad, the situation is less than ideal.
Chord interconnects have a warm signature and could be a benefit.
A preamp with balanced outputs could be an option to consider if all else fails.
Also a preamp that is warm and rich out of the box is another direction.  Various  older Conrad Johnson and Cary Audio preamps are known for their rich warm sound that can be too much of a good thing in some systems but would likely be a good match with your ATC speakers.  
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I haven’t found the home version of the ATCs, in my case the SCM19A, to be surgical (a TAS reviewer didn’t either). Plus, I’ve got AM Ultimate fuses in there, which are on the warm, liquid side, along with using PS Audio power cords and MG Audio ICs, neither of which are cool. But the Lampi TRP dac did definitely cool things off relative to the Direcstream, but it seems that was by design. Trying to make tube sound like solid state is common these days. In any case, I improved its tubes. While I await its return from repair, the Brimar CV4003s, primarily the 13D5 type, in the PL have done a wonderful job with the DS. And for the long haul I decided to go with a Supratek Chardonnay preamp, which is supposedly on the involving side and has true balanced inputs/outputs. It should be here in a couple of months.
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Gene, Test post from Tammy. 
Try a Linear a Tube Audio MZ2 for a preamp. It’s a bargain. 
The MZ2 would be functionally inadequate for my purposes. Rather, I considered the MZ3 seriously, asking on a thread in another forum site where it stands on the cool-warm spectrum, my preference being for a bit of the latter. The unanimous response was to warn me off. As I noted in my last post, "Trying to make tubes sound like solid state is common these days." No, thank you. In addition, it’s now clear that the chance of some hum/buzz in going from an unbalanced preamp to the balanced ATCs is high. That leaves the balanced version of the Microzotl, which tone/timbre aside, is over twice the cost of the Supratek, other factors aside.