The Big DAC Attack

[Wunderphones]

Greetings, all. I’m a short-term lurker, first-time poster. ASR’s testing and discussion have been pivotal in the selection of a couple items in the new listening room I am assembling, and I’m hoping that the trend can continue.

Some background before we get to the “what DAC should I buy?” portion of the program:

Back when I was young, I was a rave DJ, and I still have the equipment. My stereo setup will differ significantly from a lot of people’s, because from the beginning I wanted just one workstation that could handle both active manipulation as a DJ booth and passive enjoyment as an audiophile listener. Below you can see what I have done. I built the cart back in 2010, but back then, I put the speakers on tall stands, making no attempt to position the speakers at an appropriate level for seated listening. Now, I have bolted the speakers on to articulated arm TV mounts, allowing the speakers to be positioned up for monitoring or down for leisure listening—an innovation of which I am unseemly proud.

Originally, the cart ran through a rack-mounted pro-audio Class D amp with a fan. Now, there’s a VTV Eigentakt there in that middle cubby. This Eigentakt business is the wave of the future, y’all. It’s a shame I couldn’t rack-mount that, too.

So, the original plan was to use the DJ mixer to send XLR outs to the amp, and feed the DJ setup into the mixer’s phono inputs, with the TV and my Roon client attached to the line-level inputs. Basically, the mixer was to be my preamp until I figured out what audiophile gear I might want in that role.

Unfortunately, feeding the line-level input of the DJ mixer with the Roon output was sonically awful. I was just coming out of the Raspberry Pi USB, through a Monolith thumb DAC, up through an RCA splitter to the mixer. And the hiss was terrible. Right now, I put a Schiit Jotunheim Multibit (my desktop headphone rig) in there instead, and that’s working out fine for now.

Alright, one last historical item and we’ll be caught up: the mixer went back to Amazon when I found out Pioneer wanted me to pay them $120 per annum to use the Rekordbox software. I will replace it with something else.

Directly upstream from the Eigentakt, I will need to be able to switch between the mixer and the Raspberry Pi, and to adjust the system volume. In short, a preamp.

Any mixer I would consider as a replacement will have balanced outputs that can be run into, say, a Schiit Freya+. And then I could run the Raspberry pi into a balanced DAC that would feed the other set of XLR inputs, and use the Freya+ remote to switch between the inputs and change volume.

But, if I get a more upscale DJ mixer, I can instead run a S/PDIF cable from it. And then, with just digital sources, I would no longer need a separate DAC and preamp. I would need a DAC that had easy input switching between S/PDIF and USB and a volume knob. (I know the knob isn’t technically required, but I’m not a fan of volume controls that only have buttons.)

Whew! With all that out of the way: what DAC should I buy? Balanced outs, easy input switching, and volume control are the key requirements, but Roon Ready, rack mountability, and MQA support are all big pluses.

 

[AnalogSteph]

So far so good, now what about your budget? This is the kind of thing I would expect to be spending $500-ish on, +/- (like Gustard X16, Soncoz SGD1, Topping DX7 Pro etc.)... could go over 1000 with some extra functionality (e.g. RME ADI-2 DAC, Okto DAC8 stereo, Benchmark DAC3 L/HGC etc.).

I imagine your previous hiss problem may have been a ground loop at work (the hiss being switching power supply noise), though I'm not exactly sure why... knowing more about the power supplies of both the Pi and the mixer would be required. All the adapter business may not have been beneficial to shield resistance either.

 

[PierreV]

Now, I have bolted the speakers on to articulated arm TV mounts, allowing the speakers to be positioned up for monitoring or down for leisure listening—an innovation of which I am unseemly proud.

Very cool! Now motorize them and add LED effects.

But seriously, this is a really good idea. I have a large monitor (49") and my desktop speakers are partially behind. A desk with articulated wings could be a solution.

 

[Wunderphones]

Very cool! Now motorize them and add LED effects.

But seriously, this is a really good idea. I have a large monitor (49") and my desktop speakers are partially behind. A desk with articulated wings could be a solution.

Hey, thanks!

My initial enthusiasm for the prototype has been tempered by the realization that the springs and gas shocks in the arms don’t absorb as much speaker vibration as the turntables need. I’m investigating Sorbothane and some other ideas before I give up and move the arms off the cart and onto the walls.

I’m still pretty darned happy with the idea, and will still be happy if I can’t have my robot cart, because it’s trivial now to experiment with different speaker positionings. Even if one had height-adjustable stands, moving from one state to another would be work. And tilting them would be more work, and possibly hazardous.

 

[Wunderphones]

So far so good, now what about your budget? This is the kind of thing I would expect to be spending $500-ish on, +/- (like Gustard X16, Soncoz SGD1, Topping DX7 Pro etc.)... could go over 1000 with some extra functionality (e.g. RME ADI-2 DAC, Okto DAC8 stereo, Benchmark DAC3 L/HGC etc.).

I imagine your previous hiss problem may have been a ground loop at work (the hiss being switching power supply noise), though I'm not exactly sure why... knowing more about the power supplies of both the Pi and the mixer would be required. All the adapter business may not have been beneficial to shield resistance either.

The highlighted points, in order:

1. Ah, yes. Budget. In one sense, this whole thread is a sham, because I actually know the perfect product for me already. It’s the Mola-Mola Tambiqui. Having gotten used to the Eigentakt, I am firmly convinced of Bruno Putzeys’s status as an engineering god, and the Tambiqui does exactly the things I want. But my wife is all like, “you may NOT sell a kidney to buy a DAC!”—even though I have TWO kidneys, and ZERO Tambiqui DACs, and the optimal number is clearly one of each. Jeez, women and math, amirite? [No. No, I am not.]

I haven’t fully decided what role I want this DAC to fill. If i just want a sub-500 DAC, I suppose I am leaning toward one of the SMSL units that has the ES9038PRO in them, the SU-9 or the M500. But some of Amir’s rants about the thermal sensitivity of the 9038, and the longstanding (but probably far overhyped) concerns about IMD “hump” makes me think maybe spending a little more to get the Gustard A18 would make sense. I haven’t heard anybody say anything bad about the 4499 to date—except that it doesn’t measure as well as the ES9068, I guess. I don’t know what to make of the weird knob on Gustard DACs. It looks more like an iPod click wheel.

The main product that is keeping me from just settling on something in that range is the Matrix Audio Mini-I Pro 3. Aside from wishing it had a bigger screen, that thing is a basically perfect fit for my feature requirements, and Matrix has a track record of making good stuff. It’s not actually available right now, and I’m probably going to wait to see; I’m keeping an eye out to see if any of Wolf’s issues are resolved in the re-release next month. If the MiniDSP SHD Studio gets Roon Ready certification, I’ll definitely give that one a look, too.

2. Ground loop? I’m not sure. I had a separate grounding noise coming from the mixer, and that one was low-pitched like the descriptions I read of ground loops. The one coming from the Raspberry Pi > Monolith DAC > 3.5mm-to-RCA adapter was more like the hiss that would come out of my TV when the speakers were on but it couldn’t find a signal—the sound of “snow." A cheap USB isolator did not tame the noise, so I just took my headphone amp off my desk and put that at the center of the stereo while I worked out the mixer and the DAC/preamp. I was much less interested in diagnosing the problem than having it go away.

 

[AnalogSteph]

My initial enthusiasm for the prototype has been tempered by the realization that the springs and gas shocks in the arms don’t absorb as much speaker vibration as the turntables need. I’m investigating Sorbothane and some other ideas before I give up and move the arms off the cart and onto the walls.

If in doubt I might look for some concrete slabs / tiles. Place your turntables on those with halved tennis balls placed underneath. You can get prettier and fancier in all regards but that's the general direction I would take. I.e. a sandwich of turntable plinth --> springy feet --> big mass --> springy feet --> rack.

Also, leave dust cover open or remove during playback, they can be resonance galore.

 

[Wunderphones]

If in doubt I might look for some concrete slabs / tiles. Place your turntables on those with halved tennis balls placed underneath. You can get prettier and fancier in all regards but that's the general direction I would take. I.e. a sandwich of turntable plinth --> springy feet --> big mass --> springy feet --> rack.

Also, leave dust cover open or remove during playback, they can be resonance galore.

For just $150 per deck, I could put them on these isolation feet, which seem to suspend each corner of the turntable in a web of o-rings:

And don’t get me wrong, I want to. But it doesn’t seem like the optimal allocation of funds, does it?

 

[AnalogSteph]

People have spent far more money on things less effective. This is basically a more heavy-duty version of a shockmount as used for microphones. Should work and is not too bad in the looks department either. My solution would probably be cheaper though, even if you decide to get creative with a paint job (raw concrete quite arguably isn't the most decorative). It all depends on your priorities.

In the olden days, fancy turntables would have an elastically suspended subchassis (e.g. Thorens, Dual 7xx). Always the same idea. It was quite necessary for live playback at high volumes, especially when the floor wasn't the most stable. Demands for just ripping vinyl are substantially lower in this regard.

Using a wall-mounted shelf would be another popular option, though I'd guess this requires a reasonably stable wall (brick or even concrete), which you may not have available.

 

[TimW]

Great idea with those speaker mounts! I like how you're putting together your system, very unique and high performance. At least on the amplifier and DAC side of things. It's hard for me to imagine pairing a Purifi amp and TOTL DAC with those old bass reflex polycell Infinity bookshelf speakers.

 

[pozz]

upscale DJ mixer

Which are you considering? Haven't look at that market for a long time.

 

[Wes]

best solution is to put the turntable in another room (say, drill a hole thru that wall for the cable)

nice selfie BTW

 

[Wunderphones]

Great idea with those speaker mounts! I like how you're putting together your system, very unique and high performance. At least on the amplifier and DAC side of things. It's hard for me to imagine pairing a Purifi amp and TOTL DAC with those old bass reflex polycell Infinity bookshelf speakers.

Well, you’re not alone. But I would have been really, really hesitant to take a drill to the backs of less beat-up speakers for the sake of building a prototype, because I am a ham-fisted oaf.

The old Infinitys aren’t great, although they’re far from terrible, and I love them for sentimental reasons. But actually, I built the room around the transducers (as one does), so when the room is done, the speakers are actually the part I’m most psyched about. I’m having Salk make me some BMR monitors to take the Infinitys’ place, with professionally-installed metal inserts to receive the mounting bolts. Then some lucky punk will find the Infinitys at Goodwill.

 

[Doodski]

Then some lucky punk will find the Infinitys at Goodwill.

I used to retail those Infinities, compare them to ~40 other speakers in the sound room and they aren't a bad speaker. They are a lil bright on the top end but I like that.

 

[Wunderphones]

Which are you considering? Haven't look at that market for a long time.

I think the Denon Prime X1800 or 1850 is the most likely. Perhaps a used Pioneer 900NXS2. I love Allen and Heath and Rane, but I don’t think any of their stuff has a digital out.

 

[TimW]

The old Infinitys aren’t great, although they’re far from terrible, and I love them for sentimental reasons. But actually, I built the room around the transducers (as one does), so when the room is done, the speakers are actually the part I’m most psyched about. I’m having Salk make me some BMR monitors to take the Infinitys’ place, with professionally-installed metal inserts to receive the mounting bolts. Then some lucky punk will find the Infinitys at Goodwill.

Awesome!

I am critical of these Infinity's because a friend of mine currently owns a pair and when we hang out in his room we listen to music LOUD. Due to the layout of the room I usually sit with the right speaker pointed directly at me less than 6ft away. The guys I hang out with there are musicians with hearing damage that like to crank the bass and treble knobs on his Yamaha, so I get smacked with piercing tweeter sounds that just drive me nuts. I'm gifting him a pair of JBL Stage A130's soon, mostly for my own sake.

 

[Wunderphones]

People have spent far more money on things less effective.

No doubt. Like I said, I do want them. They’re cool.

But I figure I’m never going to be able to isolate the platter from the burly electric motor right underneath it, so it’s probably a mistake to go down the isolation rabbit hole very far. 1210s just won’t ever be an audiophile device.

 

[Wunderphones]

Well, I decided not to go full “Big DAC” with the Mini-I Pro 3.

I just went with the cheapest one—the SMSL M500. After reading about the existence of the V2 hardware bump, I figure it’s basically the same as the SU-9 measurements-wise, but with a headphone jack and $50 less. The fact that the headphone jack isn’t world-class is of no real consequence to me, since I aim to use it as a preamp.

Thanks to our interconnected global economy, having made up my mind last night, I should have it in my hands later today.

What I’m really interested to hear is whether it will sound quieter to me than my Schiit Jotunheim Multibit. There’s like 35 points of SINAD between the two of them, but listening to the Jotunheim for the last few years, I haven’t noticed anything but signal anyway.

And, of course, I will be able to tell once and for all whether I can really notice the imaging differences between the two DAC technologies.

If you just count the audiophile side of the system, even with the extravagance of custom speakers, the whole thing comes in under $4500, I think. For a system with noise and distortion levels that didn’t even exist a half decade or so ago. If you throw in the DJ side of the system, that’s like another $2K. And I’m done.

This is the point where I wonder how ASR keeps its readership interested. At sites where the subjectivists are more in ascendance, it’s always easy to find some new product that will “soar” a bit more than what you’ve got. But once you know that your gear has an inaudible SINAD level, if you accept that amps and DACs are basically fully mature technologies, there’s no reason to keep looking for something different. Speakers, I guess.

 

[AnalogSteph]

But I figure I’m never going to be able to isolate the platter from the burly electric motor right underneath it, so it’s probably a mistake to go down the isolation rabbit hole very far. 1210s just won’t ever be an audiophile device.

You've got some funny ideas about direct drive turntable motors. Properly executed, they are essentially bearing noise limited - which is to say, very very quiet. (Try a stethoscope. You might hear a bit of transformer hum.) Pretty much any Technics quartz DD 'table is rated -78 dB, DIN B, ever since the 1970s. That's about as low as it gets. A classic '1210 may have some issues with cogging, but that's a control circuitry issue and would be affecting the frequency spectrum of tones (wow/flutter), not mechanical noise.

BTW, outside of DJing you're better off using the traditional thicc rubber mat, which gives you a better VTA (the arm is really designed for that sort of height) and dampens the platter very effectively.

What I’m really interested to hear is whether it will sound quieter to me than my Schiit Jotunheim Multibit. There’s like 35 points of SINAD between the two of them, but listening to the Jotunheim for the last few years, I haven’t noticed anything but signal anyway.

As mediocre as the Jotunheim measured, the distortion isn't so bad that it should be jumping out at you right away (it's no worse than a whole bunch of AVRs at rated power and still qualifies as "hi-fi", besides seems to be mostly uncritical 2nd order), and dynamic range is still OK for a line-level source at ~90 dB. The M500 by contrast, has an output noise level lower than a fair few decent analog preamps.