[Briefremarks]

I’ve wanted to review the Overdrive DAC for a while now, but have only just got around to it.  It’s easiest for me to review the Overdrive DAC by comparing it to the DAC that I have used for a while, the Platinum DAC III from MSB.

Setup

Source is either CD transport with SPDIF output to DAC, or computer playing .WAV files with USB output to DAC.  CD transport is a Sony 7700 modified by Steve a while ago; still one of the best CD transports I’ve heard.  WAV player is JPlay on a Windows 7 machine with solid state drive.  No preamp is used.  The DAC outputs to an active signal processor (ASP) that is part of the Orion Linkwitz speaker system.  Two Emotiva XPA-5 five channel amps power the drivers in the Linkwitz Orion speakers.  Speaker cables are Goertz MI-2 (Veracity), and interconnects are from Blue Jeans Cable.  These interconnects have excellent shielding and really low capacitance.  I’ve tried all sorts of interconnects; for the most part they are poorly shielded with greater hum and higher capacitance numbers.

Conclusion

I’ll begin with the conclusion and try to elaborate.  The Overdrive DAC is a clear winner.  The primary difference between listening to the Overdrive and the MSB DAC is that the Overdrive sounds much more dynamic and “real.”  I find myself immediately immersed in the music, with instruments and voices as “real” as I have ever heard.  With the MSB, while sound is extremely detailed and resolved, I still feel, in comparison, that I am listening to a really great recording or system.  I’ve gone back and forth with many genres of music and a wide range in recording quality.  I’m sure I could find some better “review” language to describe this, but I wanted to convey the main, overall impression with the Overdrive.  I absolutely forget that I am listening to a system, recording, etc.  Everything is the music and I find myself marveling at compositions, solos, voices.  The system disappears, only music remains.

More Detail

The most immediately noticeable quality of the Overdrive DAC is the extreme realism of the dynamics. Acoustic instruments, voices, orchestras, everything sounds real.  I cannot exactly quantify what contributes to this realism but I experience it as greater dynamics—which seems to be what real music sounds like—and a more three dimensional rendering of sound, which is especially noticeably with percussion, strings, piano and horns.

The SPDIF performance is amazing, especially when I use the Sony transport, which by the way sounds considerably better than a standard Oppo 93 player.  With USB to the DAC this is the best sound I have heard in any system.  Part of the overall sound is definitely the Linkwitz Orion ASP and speakers.  These speakers in my opinion are more realistic than anything else I have heard, and complement the dynamics of the Overdrive DAC

The version of the Overdrive I have is still the original version, and I am now considering a few upgrades, including the Turboclock, the new USB module, upgraded regulators and the fanless option.  The fan on the Overdrive is definitely a distraction, especially listening late at night.  I also plan to upgrade the Linkwitz Orion ASP and the Peerless woofers to the Seas woofers.

I am listening right now as I write to Charlie Haden and Pat Metheny’s “Under the Missouri Sky,” a really beautiful work.

[Audioexcels]

Nice Review.  The Overdrive would fit VERY WELL with the Orions.  I've heard the Orions 3 times, two different places, twice at Linkwitz's, once at a friend's place.  In spite rooms entirely different, same exact sound/experience with what I heard.  Orions are an exceptional "reproduction" type of speaker, and the Overdrive or other of Steve's excellent products does the same identical thing to bring the best level of reproduction possible. 

[tpaxadpom]

Great review. Do you run single ended or balanced cables to your power amps?
A very interesting experience would be to compare the 2 dacs with the passive preamp or very high quality active preamp. I wonder how well the volume control on the MSB is implemented. Changing voltage reference of the DAC is possibly the best way to adjust the volume. I know of only a few DACs that implement this technique and Overdrive is one of them.

[Briefremarks]

I run single ended inputs to the power amps, mostly because the Orion ASP does not have balaanced outputs.  I have tried using Jensen transformers and balanced interconnects.  it's been a while since I tried that and I don' remember if it made much of a difference.  I was using five stereo Parasound Halo A-23 amps at the time.  The Overdrive volume control is unique.  As far as I know the MSB volume control is a passive attenuator.  The MSB sounds very, very good, in some ways a little more "detailed" than the Overdrive.  After extensive listening, I came to the conclusion that the detail was at the expense of a more three dimensional presentation, and that the Overdrive adds a "depth" and definitely dynamics that in the end sounds more like actual instruments and voices.

[Audioexcels]

I run single ended inputs to the power amps, mostly because the Orion ASP does not have balaanced outputs.  I have tried using Jensen transformers and balanced interconnects.  it's been a while since I tried that and I don' remember if it made much of a difference.  I was using five stereo Parasound Halo A-23 amps at the time.  The Overdrive volume control is unique.  As far as I know the MSB volume control is a passive attenuator.  The MSB sounds very, very good, in some ways a little more "detailed" than the Overdrive.  After extensive listening, I came to the conclusion that the detail was at the expense of a more three dimensional presentation, and that the Overdrive adds a "depth" and definitely dynamics that in the end sounds more like actual instruments and voices.

Can you bypass it OR make it active?  I'd bet if you push some gain through that MSB, you gain those dynamics/3-D/etc. you are talking about.  You may be hearing more detail from MSB because it is not giving the dynamics of the Overdrive, but if you find out why=volume control, then you'll have a much more level playing field IMHO.  Now an Overdrive with turbo clocks and Hynes...is a different story:)))))

[audioengr]

I run single ended inputs to the power amps, mostly because the Orion ASP does not have balaanced outputs.  I have tried using Jensen transformers and balanced interconnects.  it's been a while since I tried that and I don' remember if it made much of a difference.  I was using five stereo Parasound Halo A-23 amps at the time.  The Overdrive volume control is unique.  As far as I know the MSB volume control is a passive attenuator.  The MSB sounds very, very good, in some ways a little more "detailed" than the Overdrive.  After extensive
listening, I came to the conclusion that the detail was at the expense of a more three dimensional presentation, and that the Overdrive adds a "depth" and definitely dynamics that in the end sounds more like actual instruments and voices.

There are no other volume control technologies that can match the Overdrive.  The one that does get close is a good transformer linestage like the Music First.

BTW,  have ordered sample transformers from Japan, so I can build my own transformer buffer. This will have RCA input and XLR for the Overdrive, and RCA and XLR outputs, both active and independent so you can drive amps and subs separately.  It is evidently the best transformer technology currentlh available.  This will allow one to use the balanced Overdrive outputs and drive single ended amps or subs.  It also isolates ground between the DAC and amps.

Steve N.

[Briefremarks]

Hi Audiexcels:  I can bypass the volume control by setting the control at 0 dB.  I'll try this using a Classe preamp I have and see how the MSB sounds bypassing the volume control and using a preamp to attenuate the output to the Orion ASP.  I've been following the "simpler is better" approach, and minimizing components as far as possible.

[Briefremarks]

Hi Audioexcels: Do you have the Overdrive with the turboclock upgrade and the Hynes regulators?  I'm just about ready to get this upgrade done--it would be great to hear your experience.

[Audioexcels]

I have heard Steve's Overdrive and assume it had the turbo+Hynes but ask him about it.  It was during my listening session with a Beta OR5 w/Hynes in the test.  It beat the OR5, not by a lot, but it was obvious to me.  Obvious is, IMHO, that kind of difference that I'll pay for...i.e. not subtle.  It reminded me of hearing my own pre-dac w/batteries...all the detail/dynamics, but with that more transparent/seemless sound to it.  Hard to explain, but my memory heard the OR5 as being like my pre-dac on AC=very very good, but squeezing out that last bit, the Overdrive was able to do that vs. the OR5, just as a proper-tried-true battery supply on my pre-dac did the same.

Here's how I break things down financially speaking:

1) How much can you "reliably" get for the Overdrive you have?
2) How much for the turbo+hynes and is this the product I heard that day?
3) Based on the total pricing above, how much is the SE by comparison?  If you can have a modded Overdrive for say, $3500-$4000 vs. the SE at $6.5K?, I'd obviously go with the Overdrive.  But if you would have some $5K invested in the Overdrive, you should really consider selling it and getting the SE.

It's the same position I stand with Steve's offering of the modded OR4 vs. an OR5 w/Hynes.  OR5 w/Hynes is $350? more, sounds superior, has HDMI, is brand new and not used.  So for me, $1200 vs. $1550, I'll take the better sound for only $350.  Now if we were comparing $500-$600 modded OR4 vs. the $1550 OR5 w/Hynes, I'd go modded OR4.  Either way, however, we are at truly splitting hairs with all this stuff as a modded OR4 is just so state of the art, where the OR5 is just pushing the limits entirely, so one could easily live with either modded OR4 or modded OR5 and know they have absolutely incredible USB conversion.

[Audioexcels]

There are no other volume control technologies that can match the Overdrive.  The one that does get close is a good transformer linestage like the Music First.

BTW,  have ordered sample transformers from Japan, so I can build my own transformer buffer. This will have RCA input and XLR for the Overdrive, and RCA and XLR outputs, both active and independent so you can drive amps and subs separately.  It is evidently the best transformer technology currentlh available.  This will allow one to use the balanced Overdrive outputs and drive single ended amps or subs.  It also isolates ground between the DAC and amps.

Steve N.

Wowey:)!!!  Sounds phenomenal to say the least!!!

[tpaxadpom]

There are no other volume control technologies that can match the Overdrive. 

Steve, do you mind elaborating on what is so special about your volume control technology besides changing DAC Vref as some other DACs do?

[audioengr]

Steve, do you mind elaborating on what is so special about your volume control technology besides changing DAC Vref as some other DACs do?

what other DACs?

Steve N.

[tpaxadpom]

Steve, I hope I don't look like I have a hidden agenda here but since you've asked...
Let's say, my Museatex Bidat does just that. You can read about it in the manual: http://museatex.com/bidatman.htm
When I read your webpage http://www.empiricalaudio.com/products/overdrive-dac and watched youtube video http://www.youtube.com/watch?v=5NDvHjplaCI&feature=related (~8min) first thing I thought was either lack of knowledge or "false advertisement"  At the very least you were 10 years late with this implementation. Perhaps you have something else that is unique about your volume control implementation, and that is why I've asked if you can elaborate on that.

[audioengr]

Steve, I hope I don't look like I have a hidden agenda here but since you've asked...
Let's say, my Museatex Bidat does just that. You can read about it in the manual: http://museatex.com/bidatman.htm
When I read your webpage http://www.empiricalaudio.com/products/overdrive-dac and watched youtube video http://www.youtube.com/watch?v=5NDvHjplaCI&feature=related (~8min) first thing I thought was either lack of knowledge or "false advertisement"  At the very least you were 10 years late with this implementation. Perhaps you have something else that is unique about your volume control implementation, and that is why I've asked if you can elaborate on that.

I suspected that somebody had done something similar, but I wasn't sure who. 

An exerpt:

"The remote connects by wire to the rear Bidat panel. It works by controlling the reference voltages at the D/A converter. Digital resolution is not degraded by this control as it would be by a conventional digital volume control."

Is there any more info on this?

I would never implement it this way myself.  It will pick-up too much noise.  It is better IME to use precision resistors, preferably thin-film low-noise, and be local to the D/A circuits.  The control should be filtered for noise too.  Limiting the range is also helpful, using jumpers.

Steve N.

[tpaxadpom]

I knew it was marketing move

Engineers that do audio for living don't like to share their discoveries unless they're covered by patents. Ed Meitner has a ton of patents. You can look them up, perhaps this implementation was covered by one of them. His designs are very innovative. Just read a review of original Museatex IDAT recently added to Stereophile's archive. I never cared for his Emm Labs stuff though. I always wondered why Stereophile never reviewed them until I heard one. Now I know why.

As far picking up noise, the cable is shielded and the volume control is an aluminum brick(a heavy one). I see your point but I wouldn't make any claims without knowing how it's done and/or measured. I can not imagine having a need to get up to adjust the volume. It is so 80s...

PS: How tall is the opening of those vents on Overdrive DAC? It's not an RF cage by any means. 
This thread have gotten off the subject. I will keep my mouth shut.