PWD without a preamp- Listening session


#1

The topic of whether DACs with built in digital volume control sound better, the same or worse than having a preamp inserted into the signal chain is an often discussed topic on internet forums (such as this), audio societies and the like for years. Ultimately the conclusion that is inevitably reached is that it is listener, listening environment and associated system dependent, just like pretty much every other thing in our audio hobby. Almost 20 years ago, when I was finally able to afford good gear, I made my splash into the high end by running a Mark Levinson No. 39 directly to my amp, the set up that I used until I took the multi-channel music/home theater leap which necessitated a surround sound processor/pre-amp. I still have a multi-channel set up, but it is now completely separate from my 2 channel, including the speakers. I found that for home theater soundtracks, the peaks, dynamics and volumes associated with them added potential wear and tear on my expensive front channels that were not desirable long term. So when I returned to my 2 channel roots, I added a nice tube preamp into my mix and have never looked back.

My 2 channel system has changed relatively little, by audiophile standards, over the past twenty years, but the addition of a PS Audio PowerWave DAC is one of the additions, which I purchased to go along with computer based file serving. I sold the Levinson a long time ago, eventually replacing it with an EMM Labs CDSE to handle redbook and SACD playing duties. The PWDs digital volume control offered the option to once again forego a preamp, for everything except SACD playback at least. I resisted the urge as my Supratek Sauvignon preamp held court in my system beautifully and I really had no reason to dethrone its position of honor. It is a wonderful sounding preamp, although not without it’s faults of course, but the music it allowed to come from my system was simply blissful.

Fast forward to current day and now I find myself on the precipice of either replacing the Supratek, having a major overhaul of its internals or going without a preamp altogether as it is starting to spit, sputter and his like a bonfire. Suprateks are known to be quite noisy and mine is no exception. In fact, with my very efficient speakers, the less than black background can be noticed before the music begins to play. But when the music plays, all is forgotten. If a truly black background improves the sound then I would be forever grateful to have a quiet Sauvignon. But the noises coming from my system now are not the same that I have become accustomed. The first thing I did was swap out the tubes in all positions for with stock ones that were benched early on for a different flavor. Unfortunately my fears were confirmed as, if anything, the unpleasantries eminating from the preamp were slightly worse. My assumption is the caps, or something inside the beautiful cabinet are going. Whatever it is going on, it needed to come out of the chain so here I am returning full circle back to a digital based volume control, this time from the PWD and the EMM Labs is relegated to headphone rig duties for now.

I’ve spent the better part of a scheduled week off from work listening to my system very closely and critically and thought I’d share my findings with fellow PSA fan boys, or with anyone else who is reading this rather long post. For reference, my system is listed in the signature of my post.

First off I’ll note that the PWD provides plenty of output voltage to the Classe’s via balanced cables. I have an 8m run of IC’s downstream of the captive Steradian room EQ of the Whisper. I found that volumes between 40 and 50 provided my typical listening volume, which is actually fairly loud for most music. Volume changes are silent and easily handled via JRemote or Roomie Remote on my iPad (now Simple Control). Files were streamed via JRiver MC21 running on a Mac Mini with connected Firewire WD external hard drive over the network to the Bridge II. For the most part, resolution was NativeX and filter was set to auto (some exceptions on the filter due to personal taste). Now, to the music.

I decided that in order to make a fair comparison I would need to listen to either music that was etched deep into my mind on my system, or that I had recently played before the preamp started acting up. All tracks were 16/44.1 redbook unless otherwise specified. I’ll try to be brief regarding each selection then will sum it up at the end.

Jascha Heifetz/Fritz Reiner- RCA Living Stereo Tchaikovsky Violin Concerto- This is one my go to recordings for violin and its associated sonic nuances. There are many great recordings of this work out there, I own several, but this is the one I recently listened to at home after hearing it played by my local classical radio station in the car. Listening via the Supratek, Heifetz’s violin, presumably a Strad but I don’t have the liner with me at the moment, was clear as crystal with a lightness and delicacy that the master possessed above almost all others. The thing that was so obvious was the highs. Violins produce a tremendous amount of overtones, that’s partly what makes a Strad a Strad, and the Supratek reproduced the recording with an ethereal quality that had the upper registries of the violin lilting off into the stratosphere. With PWD direct, everything was present and accounted for except the magical etheralness, to coin a term, to the violin. Without the tube preamp, the sparkle and air in the upper registers was notably absent. It still sounded fine and had I not specifically noticed the way his violin sounded just a few days prior I might not have noticed the difference, but it was not subtle in my mind.

Round one: Supratek

Holly Cole- Don’t Smoke in Bed- Almost veryone knows this disc, probably by heart. On the opening track the pitch of Drew Piltch’s upright is critical. I’ve heard this track time after time on various systems and its odd that on some of them, the bass can sound just a bit off pitch relative to Cole and the piano. The piano can likewise seem to stretch unnaturally large. Everything was just perfect with or without the preamp, which surprised me honestly as I expected the female voice to really shine with the preamp. Bravo PWD for keeping up. Cole was centered perfectly between the speakers either way but she was perhaps a bit larger than life and seemed like not quite as focused with just the PWD, but it could just be my memory being a little fuzzier than I want to admit. Both ways portrayed the echo of the recording environment exceptionally well, providing a good acoustic window through which to peer into the recording session. There was something, though, that was obvious on this track that would be a recurring theme in the jazz numbers that I listened to. Without the preamp the sound was just a little dead. Usually jazz bounces and lifts you, which is always the case on this number for me as the bass bounces and plumbs from beginning to end. It didn’t bounce quite as much without the preamp.

Round two: Supratek, but by a small, almost negligible margin

Piltch and Davis- Feast- This is a new disc to me but I’ve recently listened to it a few times. There is a lot of great bass work by Holly Cole’s bassist, as well as acoustic guitar and various rhythm instruments. Here the bass is given appropriate weight and the low register was particularly full either way. The guitar is mixed a bit quietly to me, but still always audible. There’s not a lot of guitar picking or fret sliding squeak on this CD so I can’t really flesh out a lot of the resolving differences on this one. There is a good amount of percussion, with plenty of cymbal work for example. I expected, after my observation with Heifetz, for the preamp to really shine here but the PWD held its own just fine. All the detail of cymbal strike, vibration and decay were there and if there was any loss of upper register detail present I couldn’t hear it. The bass was perfectly in tune on both once again. I don’t know the recording well enough to know the pace and timing, but the two portrayed things pretty much the same to my ears.

Round three: Tie

Big Phat Band- Swinging for the Fences- Ok, so if you are a fan of big band or jazz music and don’t own this CD, stop reading and go buy it from your favorite music source. This is a big band recording for the ages, IMHO, and one that I never audition without. The opening track, Sing Sang Sung, will reveal more about a systems dynamics, pace, resolving ability, rhythm and timing than just about any other track available. The track starts out hot with brass, bass and drums and builds from there, adding winds a few stanzas in and it is hot, hot, hot. From the whack of the snare to the bite of the brass to the drive of the upright, it is all I can do not to hop out of my chair and delve into my best imaginary air upright bass playing. Don’t laugh, you know what I mean. But this revealed probably the biggest difference between having the preamp and not out of all of them. Normally the percussion strike, bass plucks and staccato ensemble explosion will hit you in the chest and pin you to the chair. This is a wonderful experience with the Supratek, but without it, that attack seemed to stop about three feet in front of me instead of hitting me in the chest. The dynamic punches were just lacking. Likewise, it seemed as if the tempo was slower, maybe 110 beats a minute instead of 120 and the whole piece seemed to be less exciting than usual so the PWD really let down on the pace and tempo unfortunately. There is a lot of resolving to do on this disc as well. Differentiating the individyal trombones, trumpets, bari sax then the multiple tenor and alto requires some deft work on the equipment’s behalf. A close listen displayed either way, one could clearly place which instruments were which and where in the midst of a sonic barrage assaoult.

Round three- big win for Supratek

Roberto Alagna- Debut album. Being a tenor way back I’m a sucker for them and Alagna was the heir apparent I thought when he released his first album. Pourquoi me Reveille (track 3) and Che Gelida (17) were portrayed fantastically by both methods. Alagna is less spotlighted on this recording than most opertic recordings and the sense of size, space, acoustic and vocal artistry were equally portrayed. As with Holly Cole, Alagna’s voice was a bit wider without the preamp, but not unbelievably so and it is more acceptable in this environment than the intimate studio or club.

Round Four- Tie

Nicklecreek-This Side- This is a very bright, treble heavy recording. It also is rife with detail and reveals the transparency and resolving ability of equipment, as well as imaging. From the pluck of the mandolins and bass to the presentation of both male and female vocals, both were outstanding. I thought the PWD might actually outperform the pre because of it’s slightly subdued treble once again, but no, they were both fantastic and non-fatiguing. What did surprise me, however, is how much wider and deeper the soundstage was without the preamp. This was the first time I had to think that I preferred the preamp less. On track 5, I Should Have Known Better, there are various percussion instruments that emanate from outside the boundaries of the speakers. With the pre, I estimated a good three feet out on each side. With the PWD, it was more like 10 feet and actually threw an auditory image almost parallel with my ears side to side. This was really outstanding, as were all of the tracks on this album via the PWD.

Round Five- Big win for PWD

Roger Waters- Amused to Death- With it’s novel omnisound or circle sound, whatever it was called, this proved that surround sound through two speakers could be achieved, which we see all the time in HT now. Both components placed objects beside and behind the listening position, as well as appropriately in the front plane as well. With so much encoded trickery, it was too hard to tell any difference, but my main reason for using this was to check holographic imagine, which they both proved very capable indeed.

Round Six- Tie

Vladmir Ashkenazy/Andre Previn/LSO- Rachmaninov Rhapsody on a Theme of Paganini 24/96 HD Tracks. The first high-resolution file here. I’m a big Rach fan and this works particularly for auditioning because of the clear placement of insturments in the soundstage, left to right as well as front to back. The piano is highlighted enough as not to be lost in the mass of instruments but doesn’t stretch across the entire stage. The clarity of the piano on this recording is stellar and both presented it with detail and weight when called for. My previous favorite recording was Earl Wild on Chesky, but this is every bit it’s match. What really separates this composition for me is the intricate interplay and doubling of the piano line by various woodwinds such as flute, clarinet, oboe, etc. On lesser quality recordings and lesser equipment, that detail is often buried or lost. I could plainly and easily hear the fast moving woodwind soli without difficulty either way. The soundstage was deep on both with front to back layering presented in a lifelike manner, which means that there was some depth to the orchestra, not just laterality. That can be hard to discern even in a live concert but with the help of specifically placed recording gear, the illusion is alive and well on this recording and the PWD passed with flying colors and so did the Supratek.

Round Seven= Tie

Nina Simone- I Put a Spell on You- 24/192 HD Tracks. The second high-rez file of a classic recording. Unfotunately the master really doesn’t help you flesh out too much here. Nina’s gravelly toned soulful voice was excellent in both. Instrumentals were as they should be with no real discernable difference to my ear. This probably wasn’t a good album to use but hey, if one or the other fell flat it would have been meaningful.

Round Eight= Tie

Dire Straights- Brothers in Arms- One of the better recorded rock/pop albums of its genre and is a nice evaluation album. Knopfler’s voice is rich and nicely depicted out of both. The sax in Latest Trick is layered behind him and its easy to tell when the sax player turns around away from the mic on both. The guitars are well presented with the appropriate pedal mix. The soundstage is excellent but a bit wider, perhaps less focused again through the PWD.

Round Nine- PWD but could just as well go to the preamp

Branford Marsalis- Trio Jeepy- This is another oldie but a goody and I love to use this disc because it’s easy to focus on individual instruments without being lost in the fray. On track one, the plucked upright is crisp, clear and full of body anchored the center of the soundstage perfectly. Marsalis’ tenor pops just a bit more with the preamp in place and feels a bit more resolved as well. Both throw the sax outside the left of the speaker nicely, the PWD alone placing it just a bit further out once again. The drum kit far right and without the preamp, it feels like it is a bit wider and more life-sized. The cymbal work as well as head strikes pop more with the preamp. Track six, Gutbucket Steepy presents more of the same with a well-anchored bass solo starting us off. Extension down into the lower registers is well portrayed and the pitch is spot on but could feel a bit bloated without the preamp. There’s a lot of hall echo that is nicely captured on this track as well and both really present a “you are there” sonic image. The pace, once again, goes to the preamp though. It kind of feels like the beat is a tad slower once again with the PWD by itself.

Round Ten- Supratek, but not by much.

Creed- Human Clay- This is rock. It sounds artificial because it is. I love rock though and find that Creed is at least EQ’s well and is decently clean. I found the opposite to Jazz here with the PWD feeling like it hit a bit harder than with the preamp. Other than that, the bass lines are there, but never as prominent as I would like. The guitars are gritty with the distortion just like it should be. Stapp’s raw baritone sounded a bit rawer without the preamp to me.

Round Eleven- PWD

Stan Getz/Joao Gilberto- What a fantastic recording this is and has stood the test of time as an icon for the audiophile. Joao’s voice starts out all mellow and right in front, between the speakers. On the PWD , the voice is once again a bit larger than life and slightly out of focus. The guitar is just inside the right speaker. When his wife takes her turn, however, the focus and size is spot on. On my system, she is standing right at the right speaker, next to the guitarist with the preamp. Without it she’s a foot or two outside of that. The piano is behind her a few feet with the preamp and more like five or six without. To the left, the drum kit is anchored just behind the speaker a few and expands just a bit to each side with the preamp. The PWD again spreads it out a little wider, as it should be. The bass, well without the preamp I couldn’t clearly place it in space at first. I think it’s in front of the drums on the left but without uncertainty. With the preamp, I’m convinced that’s where he is almost from the get go. Actually, later on in the track, even without the preamp, I can place the bass outside the left side (right channel) solidly. When Getz comes in, the sax has a lot of air and spit in the mouthpiece and neck, which gets thicker as the song goes on. There’s more of it with the preamp and the instrument as a whole has more space around it and is better focused.

Round Twelve= Supratek for transparency, PWD for soundstage.

In summary:

With the Supratek preamp: More focused, more detail, much better pace and tempo. Soundstage is narrower.

Without the Supratek preamp, PWD to amps: Wider sound staging, perhaps even a bit more depth with surprising resolution. It does lose a bit of focus and quite a bit off pace and dynamics.

Those are my listening impressions for the week. There is certainly no loser here in my current system. I was hoping to hear a distinct and clear winner and I have to give the nod to having the Supratek in the chain. The question of whether I can live without a preamp on a sound quality basis still remains to be seen. Of course I want it all, I’m an audiophile. While the soundstage was notably wider and possibly deeper without one, I never felt like is was narrow or shallow with it in place, quite the contrary actually. Sometimes systems throw unrealistic images that are not to my liking. I once hear Holly Cole standing 10 feet tall through a pair of Von Schweikert VR-4’s for example. If anything, the PWD expanded the soundstage to appropriate size, nothing more. But its lack of dynamics and drive relative to having the preamp in place made it feel just a bit on the sterile side, as do most laid back components. I have a hard decision to make and, as always, the law of diminishing returns applies. The final straw, however, is that I have two sources. Since there are no affordable solutions for SACD transports to match with a Direct Stream, and I don’t have any way of ripping my 200 plus SACD library to .dsf files on my own, a preamp will be required, otherwise I might just do the upgrade to the Direct Stream and call it a day. I happen to have my eye on a nice one that is just now coming available ;).


#2

Excellent post speeddeacon! Lots of good information and I think you came to a similar conclusion as others have regarding use of a preamp. Personally I prefer no preamp with my DS, I was mixed on the PWD. Rather than detail that, a question for you. What volume were you running on the PWD when used both with the preamp and without?


#3

Thanks Pmotz,

I always had the PWD at 100 running through the preamp. Straight, running 40-60 so am shaving lots of bits off running it that way for sure. It definitely would need an attenuator to be used this way for good. It could account for the lack of dynamics too, I just couldn’t try it at 100 straight, but would love to hear others observation too. I’ve read some on the board of course.

Tell me about your experience running the DS straight compared to PWD.


#4

Speeddeacon, when I had the PWD I was running it into an Audio Research Classic 60. It worked but similar to your experience I was running in the 40-60 range so I was losing some data. When I ran it through my Audio Research LS 25 preamp the sound was fuller and more dynamic. If this was due to the loss of data or something else I really did not know, it just sounded better with a preamp. As such, when I had the PWD I used a preamp. To be clear, I asked the volume question without giving too much detail so as to not bias your answer. You gave the correct answer! I would say you are experiencing the same thing I and others have.

With respect to the DS, when I got it I once again compared with and without the preamp and was pleased to find without the preamp it sounded more dynamic, open, and with better bass. As such, I was happily using it without the preamp. About six months ago I got a BHK250 and reran the preamp test, I was once again pleased that it sounded better without the preamp. This time I sold the preamp (better to afford the BHK!). The DS has the advantage of a 20 dB attenuator built in which helps with matching it to the input sensitivity of the amp. I generally run the DS with the attenuator engaged, though I will say I think it sounds better without the attenuator. The downside is I start running in that 40-60 range (this isn’t as bad a thing with the DS, but …), so I save running without the attenuator for when I am listening to low output sources or I want to listen loud!. I should also add that with the BHK I was able to run fully balanced, something I could not do with the Classic 60. Balanced is the way to go for the PWD or DS!


#5

I have yet to post about this but I was shocked to find the DS sounded better direct to my BHK 300’s. I did not find this to be the case with the PWD (1 and 2). I also find the -20 DB on the DS to completely kill dynamics and transparency.

I am about to try my excellent and pricey preamp again now that the bhk is Broken in.


#6
emailists said I have yet to post about this but I was shocked to find the DS sounded better direct to my BHK 300's. I did not find this to be the case with the PWD (1 and 2). I also find the -20 DB on the DS to completely kill dynamics and transparency.

I am about to try my excellent and pricey preamp again now that the bhk is Broken in.


I have to echo this in my own experience. I love my preamps, and one definitely is in use for my phono preamp and universal player output, but the DirectStream sounds a bit better directly into my amp (which also has a stepped attenuator gain input, so I can “ride the gain” a bit. The PWD sounded a bit better with the preamp.

#7

[nested quote deleted]

What attenuators are you using?


#8

Those of you that are finding that the DS, as opposed to the PWD, sounds better direct than with a preamp present an interesting thought for my situation. There is a mixed bag of results over on the DS thread. I’ve been waiting for the right “budgetary opportunity” to upgrade the PWD to the DS since the DS came out. If indeed the “want” of a DS is supplanted by the “need” of a new preamp, I then have to ask myself if the DS upgrade would accomplish both. The common denominator though may be the BHK’s. Paul, et al, may have a combo that will render the upcoming BHK preamp unnecessary, LOL.

Given how well the PWD performed in my system though, if the DS could actually remedy the limitations of the PWD, hmmm. That route would limit me to a single source though, which wouldn’t the end of the world, but being honest, would probably lead me to still be in the market for a preamp in the future.

So so I wonder, input switching notwithstanding, which equation would be most true:

PWD + pre + amp (<, =, > ) DS + amp.


#9

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#10

I too would say < with the caveat that the voltage output of the DS is enough to get you the output level you need from your amp. With one of my sources connected to the DS and going straight into my 25 watt per channel tube amp it is just barely so. Other sources connected to the DS offer plenty of gain. The PWD does put out considerably more volts than the PWD.


#11
lonson said I too would say < with the caveat that the voltage output of the DS is enough to get you the output level you need from your amp. With one of my sources connected to the DS and going straight into my 25 watt per channel tube amp it is just barely so. Other sources connected to the DS offer plenty of gain. The PWD does put out considerably more volts than the PWD.
In the last sentence you mean DS puts out more or less than the PWD?

That’s interesting that it can be source dependent. Is it true on all inputs or could it ne input dependent, I.e. XLR vs. SPDIF, USB, etc.? I don’t know enough about how DACs handle impedance, voltage or gain on the input side to know if that is typical.


#12

The output of the PWD is greater than the DS.


#13

Right, the PWD puts out considerably more than the DS.

It appears to be component related, not digital input related.


#14
lonson said Right, the PWD puts out considerably more than the DS.

It appears to be component related, not digital input related.

Elk said The output of the PWD is greater than the DS.
Gotcha, that is indeed good news for me then. If I could run it between 75-100 I would be happy I think.

So that one component with low output is low regardless of how it is connected? Interesting.


#15

I spoke with a service guy regarding my preamp and he recommended trying a different rectifier tube as he felt it was a power supply issue. I got my hands on another 5AR4 and sure enough, all the ails were gone. So now I’m back in the preamp business and am shopping around for a Direct Stream or DS upgrade board. I am thrilled that my pre is fine and I can move forward with upgrading the PWD, but I was also looking forward to buying an Aesthetix Calypso.