[Tyson]

Been working a lot with my system lately, really getting down to fine tuning it for best sound with the AVA stuff (T7 pre and 550ex amp).  I've finally gotten it to where I want it (the Siemens tubes in the AVA gear was the final piece of the puzzle).  I've got the system sounding really good, so I thought I'd do some comparisons between my Scott Nixon TubeDac and the Mensa DIO.  One word of caution on the tubedac - it inverts phase, and has a lower output (only 1v).  To do a fair comparison you must not only adjust the volume, but you must also flip the speaker leads to get the phase correct.

I won't beat around the bush too much.  In my system (and for my preferences) I liked the Mensa quite a bit better.  It just sounded more vibrant and lifelike to me.  The TubeDac sounded more laid back (not necessarily a bad thing), but also vieled in comparison (that is a bad thing).  Listening to Johnny Lang's "Lie to Me" CD, I noticed that the tubedac made him sound a bit older with a bit deeper voice, but he (and his guitar) just seemed a bit distant.  With the Mensa, there was a snap to the sound, an immediacy that was more appealing to me.  Don't get me wrong, the TubeDac is a nice sounding unit, but it is a euphonic presentation that makes some CD's more listenable than they might otherwise be, but at the same time will rob some life/dynamics/vibrancy from other CD's, to the music's detriment.  For female vocals (I used Natalie Merchant, Jewel, Pat Barber), the TubeDac is like honey, very, very nice indeed.

One thing to keep in mind is I have tubes in my pre and amp that are already giving me that bit of "tube magic", and my system sounds ultrasmooth with both the Mensa and the Tubedac, so I don't really "need" a tubed source.  However, I think in some systems (especially all Solid-State) the TubeDac is just the ticket.  It softens and rounds out the sharp edges in a digital/solid-state system very nicely.

Also, the results I got with the TubeDac (it's actually a pretty impressive sounding unit for it's size and price class- I picked it up used for $250 ) were achieved using the Power Supply I got from Bolder for the Mensa - the stock power supply that came with the unit isn't even worth the cost of shipping to have it sent to you.  In a word, it sucks.  Also, the stock tube (a Sovtek 6922) is not particularly good either.  I changed it out with a NOS Siemens, and it sounded much better (of course, with the power supple and tube, we're now pushing over $550 on cost).  I'm actually glad I have the tubedac, I'm going to use it in my dedicated headphone setup, where it's slightly vieled nature will be offset by the proximity of the drivers to my ears.  The fact that I tend to listen for hours at a time will make the somewhat laid back nature of the TubeDac very welcome.  But for the main system, it's an easy choice - the Mensa.

My system:
nOrh CD-1 as transport
Bolder Cryo Treated Digital IC
Mensa DIO w/Bolder power supply
AVA Transcendance 7 preamp w/Siemens NOS tubes
AVA FetValve 550ex amp with Siemens NOS tubes
Bolder Cryo Treated Bybeed Nitro's
Bolder Cryo Treated Nitro Speaker Wire
VMPS RM40's with Auricap upgrade
Bolder Bybee'd Power Bar

[randog]

Tyson,

Nice review. It sounds like you may be getting tubed-out!  

Did you try the TubeDac 'unphased'? I heard a report from one person that he couldn't tell a difference in his system when he reversed his speaker cables and I'm curious if you could tell a difference on your setup. I know it's not correct usage, but the phase issue keeps me from pursuing the TubeDac further (got other sources to consider).

Randog

[Tyson]

Funny story about the phase.  It's pretty easy for me to hear when phase is inverted.  I know the DIO preserves phase, but after having it hooked up for about a week, everything was just sounding so distan and uninvolving.  Tried lots of tuning on the RM40's to "fix" it.  Nothing worked.  I figured the Mensa was just still breaking in.  On a lark, I switched the leads to my speakers.  Bingo, there's the stuff!  Something else in my system must be inverting phase & I just didn't realize it.

So, yes, I can hear the difference between proper and inverted phase, and the above just goes to show that you just gotta trust your ears with this type of stuff.

[Tyson]

Oh, one other thing, the VMPS speakers are all 1st order crossovers, so I don't think I have special hearing or anything, just that this is easier to hear on a phase coherent speaker.

[doug s.]

afaik, there *is* no such ting as proper phase, at least consistently:  the software varies phase from one recording to the next, even from one cut to the next on the same recording.  good luck trying to figure it out from song to song...    

my pre has a phase reversal switch; much as i love the pre, i could easily do w/o this feature...  i've only played w/it a few times, more outta curiosity than anyting else.

if ya wanna try one piece of source equipment that's outta phase w/the rest of yer gear, & yure concerned about it, ya can yust reverse the connections to one pair of interconnects at one end, & use 'em for that particular piece of gear...

doug s.

[Hantra]

Tyson:

Good review.  

I find that non-oversampling in general is not something that people can love right off the bat.  It does take a bit of time, and critical listening to understand what non-oversampling does for you.  

I have done the exact comparison that you did, and my results were quite opposite.    That's what makes audio fun I guess. . .   In fact, I didn't find the Mensa power supply to help the SN DAC all that much.  I suppose it depends on your power source to begin with.  I have found the SN to get much better with a nice conditioner.  Unfortunately, one that is nicer than I can afford . . .

Anyhow, all non-oversampling DAC's sound like you describe.  There is a lack of "sparkle", and less "sizzling" than with oversampling and filtering DAC's.  In the non-oversampling camp, we call this sparkling "digital noise".  

As a matter of fact, I am about to head out to a concert as we speak.  Every time I go to a show, the extra "air" and "sizzle" that audiophiles so often speak of when listening to digital playback systems, is just NOT there.  

I find it neither laid back, nor veiled.  I find the bass tighter, and more natural, and the highs sound more like the highs I hear at a live show.

Then again, that's why there are hundreds of high-end companies making thousands of products.  Nothing is everyone's cup of tea.  

But for those trying the Nixon DAC, or any non-oversampling DAC, I would encourage you to give it more than just a casual evening of listening, or a shootout with your favortie oversampling DAC.  See which one sounds more like real music.

L8r,

B

[randog]

if ya wanna try one piece of source equipment that's outta phase w/the rest of yer gear, & yure concerned about it, ya can yust reverse the connections to one pair of interconnects at one end, & use 'em for that particular piece of gear...

doug s.

Really
Does that accomplish the same thing  
That would be cool since I plan to make all my own interconnects anyway.
Am I going to sizzle anything      

Randog

[Hantra]

Does that accomplish the same thing

That works, but it doesn't work as well as doing it at speaker level.  

I cannot explain why, but it sounds better when I reverse speaker leads than when I wire my interconnects out of phase.  I just reverse phase on the phono cartridge, and voila!

B

[cjr888]

Thank you for the comparison -- its one I'm sure plenty of people have asked for or wanted to know about -- plus a lot of the folks here have heard at least one of the units, so have a point of reference.  

I think most people that have used both find one or both of them to be rather impressive in comparison to a lots that out there, and at a great price.  Sounds like they are both in the top lists for real value, and regardless of how each executes its design, right or wrong, people tend to go to one side or the other.  I got this impression from a lot of the comments here and at AA regarding systems at MAF...  There was a lot that implied that camp A loved one sound and hated the other, while another camp was the complete opposite.  It interesting, but frankly it was refreshing.  Not just to get 100 different opinions out of 100 people, but to get some common ground....with equal opposition.  The different ways that people describe what they hear sort of came together and you got a better idea in your head of how people perceive audio and what they are after.

Anyone else that does get to compare these units down the road, side-by-side or in seperate sessions, I'd love to hear impressions.  They are both unique products, one being a heavily modified unit originally sourced for pro audio, and one being a DIY/one-man-band operation based on a completely different viewpoint of how to do digital.  

Tyson -- as you're holding onto it, if you have the opportunity to drop it into other people's systems at some point -- coax them into giving them their impressions, or if you find synergy in another system, please mention.  Always curious.  And drop me a line if you ever consider selling it.  

To me, these are the interesting audio reviews and comparisons.

Thanks again.

[Tyson]

I'm leaving in the tubedac for a few days to aclimate to it a bit.  Will post an update on Sunday.

[Marbles]

I'm leaving in the tubedac for a few days to aclimate to it a bit.  Will post an update on Sunday.

What setting do you use with the Mensa?  Ext. synch or something else?

[doug s.]

randog,

ya, wiring ic's outta phase is yust switching hot to ground.  same as w/the speaker wires.

hantra, how'd ya ever figure out how to wire yer fono-cartridge outta phase?     didja find it still was yust like the outta-phase i'c's - not as good as the speaker wires?

also, re: upsampling - the di/o is *not* an upsampling dac, tho it *will* accept any digital signal input between 32khz-100khz.  tho, i do agree that upsampling may not always be a panaccea - i bought a gw-labs dsp upsampler, thinking my modded di/o would love a 96khz upsampled input, but, the music became hard, harsh & irritating, so i returned it...  the gw-labs' non-upsampling mode made no difference whatsoever, btw, indicating the extra cabling and a quality interface box introduces no sonic degradation - which is why i decided to go w/a toslink output cdp into an interface box, & into my di/o.  the low-budget aiwa xc-37m 5-disc cd changer makes an excellent transport, imo.

oh, & one other comment re: relative costs,  i tink wayne offers excellent walue for the money ya spend, but, if money is tight, ya *can* diy a modded di/o yerself w/similar results for quite a bit less money.  all the mods are well known & well documented.  i tink i have ~$350 into mine, & it would cost quite a bit less than that to do another one, cuz i wouldn't be replacing anyting more than once this time!  

doug s.

[eico1]

reversing single ended interconnects will screw up your grounds, reversing speaker cables will not as the speakers are 'floating'.  Also, if the tubedac is not enough presence for you, maybe try the dackit. The square waves on that thing are out there, I don't think there's any roll-off. I'm not a proponent of spending $400 to change resistors, so the whole assembled dackit at 250 is relatively affordable.

steve

[TV Man]

Hi,

Figured I'd add this to the discussion.

My DacKit went through a huge transformation at about 300 hours of use. I would characterize the sound prior to 300 hours just like Tyson described it... smooth as honey but slightly veiled and distant.

After about the 300 hour mark WOW!!! something REALLY NICE happened. The mids are still silky smooth but the highs gained detail and are now really, really nice. Not harsh at all, but smooth AND detailed with just enough sparkle to them to sound utterly real like Hantra describes them.

I think this is due to the Black Gate caps in the output finally breaking in. I have read similar things about the AudioNote  DAC with it's Black Gates.

I have the passive output DacKit and use the Kusonoki 5v on the 1543 and 1k I/V resistors instead of 8v and 1.69k. When I was using Scott's parameters the Black Gates were not broken in yet so I can't say which operating points are actually better sounding in my system, but I am VERY happy with the way things sound now.

The next step will be the tube output add on board... Scott's working up the details to use a 6H30 valve THANK YOU Scott!!!

We'll see how she sounds with an active 6H30 output... Honestly I can't wait to try this because I've got a hunch this is going to be a super nice addition.

My listening biases tend towards a smooth analog sound that retains good detail. Anyone who heard the Quad ESL vinyl setup at THE show in Vegas knows where I'm coming from here.

I agree with Hantra when he says the treble from the DacKit is more like what you hear at a live performance. The treble from my other DAC now sounds overdone and artificial in comparison.

I have never head the smArt D/IO so can't add any thoughts there. I do use a Boulder Cable .5 meter Bullet Plugged digital cable and was pleasantly suprised at what a big difference it made. With that experience it wouldn't suprise me at all if the smArt DI/O is an excellent DAC.

One of the things I truly love about this hobby is being able to buy my toys from guys like Scott and Wayne. I will never buy something for my system from a large international hifi company again if I can get what I need from one of the "small guys." The personal attention and superior products from them will win my purchasing dollars every time.

[ABEX]

I am glad I got the smART in the first place. Now if I can sell something after getting the LeAmpII's in order to get the MENSA version.

Nice Review!

[ABEX]

I am glad I got the smART in the first place. Now if I can sell something after getting the LeAmpII's in order to get the MENSA version.

Nice Review!

[Nelgan]

Tyson,

Where do you prefer to have the "Warmth" knob set for listening? I bought a standard DIO quite some time ago and was disappointed. But it seems that mods for this unit may have brought it up to a new level of performance.

[BikeWNC]

Hi guys, I've been chewing on this "sounds like what I hear at a live performance" issue since it was raised in the NC DAC comparison.  What bothers me about live performances, and don't get me wrong cause I love them, is that what one hears in the 5th row is different from what is heard elsewhere in the hall.  Even among relatively similar listening positions, the same performer would sound different when the venue is changed.  The thing about a live performance is it is rarely consistent sonically.  Even in the best halls, there are so many factors that can affect the quality of what one hears on any given day.

The one constant I hear at every live performance is noise.  Whether that noise is in the form of screams at a rock show or whispered conversations in a jazz club, its still noise not part of the music being produced.  Even in a church, people can only be so quite, and so the noise floor is raised.  At some shows this issue is overcome by raising the volume to improve the S/N ratio.  With too much volume can come loss of hearing sensitivity (bye-bye microdynamics). We've all had that ringing in the ears after a loud rock concert.  We'll that ringing was there during most of the show too.  Perhaps rock concerts are an extreme example.

I read so often, on this forum and others, how a particular piece of equipment lowers the noise floor.  We're probably all agreed that is a good thing.  How can people turn off things like refrigerators when they listen to their systems when in a live environment noise is such an integral part?  Because it's not part of the recording.  But that live recording was engineered to remove most of the ambient noise that was present during the performance.  And the studio recorded version is devoid of the noise experienced at a live performance.  So where does the truth lie?  Anywhere you want it to be.  No matter how good our equipment we're all at the mercy of the recording engineer.  In the end our home systems will only produce a vignette of the grand scope of most live performances.  But that doesn't mean it can't be a pretty picture.

[doug s.]

eico, mebbe the grounding issues w/building outta-phase ic's is why hantra prefers the sound when switching speaker wires.  this may be a system-dependent thing...


neil, the tube in the di/o is only in the adc path, not the dac path, so the warmth control does nothing for typical cd playback.  most folk not using the di/o for adc actually remove the tube.  for better performance, at the wery least, pick up a ~$4.00 3.4amp atari p/s from hosfelt.com...  for any/all info ya ever wanted to know about modding a di/o, go here:

http://home.ca.inter.net/~cfraser/DIOFAQ.htm

doug s.

[Wayne1]

Tyson brought over the TubeDAC to try out in my HT. It did lend a very nice warmth to my all solid state system that was missing. I did find (for my tastes) that the bass extension and detail of the Mensa were more preferred to the midrange warmth. The sound of the TubeDAC with the stock power supply was quite a bit different. We couldn't really stand to listen to it for more than half a song before we switched back to the Mensa supply.

I have to agree that in some systems the TubeDAC might be a better choice than the MENSA. For me, I am looking at getting some tube monoblock amps now