A brief recap of the Nova's specs is in order before an explanation of what I call The Nova Sessions. The Nova consists of an 80 watt integrated amplifier, Class A <30 ohm variable preamp-output, five transformer coupled digital inputs, user selectable on/off 6922 tube output stage, three analog inputs, a galvanically isolated USB stage, ESS 9006 Sabre DAC, eleven regulated power supplies for the DAC, home theater bypass, and a Class A tube headphone section. I utilized every feature except the headphone output during The Nova Sessions. The music server used was a Mac Pro running OS X Snow Leopard and Windows 7 64-bit. The components and configurations used are as follows.
Needless to say the Nova looked like a high end audio Medusa with a plethora of cables coming out of the unit. There isn't enough time left in 2010 to compare every component and interface combination possible. I used some logical combinations to compare the Nova's DAC to that of the DAC1 PRE, Proton, and DLIII. I compared the interfaces on the Nova to determine what sounded most accurate to my ears. I also bypassed the Nova's DAC and Preamp section to single out its amplification prowess when connected to the DAC1. All of these comparisons must be taken with an abundance of caution. Singling out a single interface, DAC or any one piece of these components is nearly impossible. One can only try different configurations and report sonic impressions related to those configurations. Each of the DACs involved has its own analog output stage that suffers from its own coloration. In addition auditioning the coaxial S/PDIF interface of these components I used the ASUS audio card that may have limited or enhanced the performance compared to other digital I/O cards available. Hopefully readers can use my impressions as data points to supplement their own listening sessions and cross reference my words with those of many other people who've used these components.
The Nova Sessions - No Pictures, No Large Print, Just Results
- Mac Pro OS X > USB > Wavelength Audio Proton > Analog RCA > Nova AUX3
- Mac Pro OS X > USB > Nova USB input
Listening via the Wavelength Audio Proton connected to the Nova's AUX3 analog input produced a very noticeable background fuzz. This fuzz was absent when listening via USB straight from the Mac to the Nova. This is likely due to volume control compatibility "issues." I was unable to find the right combination of volume level on the Proton and volume level on the Nova. The closest to satisfied I got was with the Proton's volume set to 94. When the proton was set around 90 or below I had to turn up the volume on the Nova to one or two o'clock. The background fuzz was apparent in this configuration as well as with the volume in the mid 90s. However with the Proton's volume set in the high 90s I heard major distortion. This was remedied by turning the Proton's volume down and the Nova's volume up. I did not use the Home Theater Bypass feature of the Nova in this configuration as I'm not a fan of using the Proton's software based analog volume control directly connected to an amplifier. Many CA readers have absolutely no problems using it this way. As I stated in my review of the Proton I don't like depending on software volume controls that may not be as responsive as I need at any given moment. All of this aside the sound of the asynchronous USB Proton DAC was superior than feeding the Nova's USB input directly. The Nova smeared the overall image and severely hindered the decay. Cymbals appeared to face much more naturally via the Proton's DAC connected to the analog input of the Nova. The Nova made voices sound good and a little larger across the sound stage but suffered from a little less definition via it's own USB interface.
- Mac Pro OS X > Airport Express (wired) > Nova optical digital input 2
- Mac Pro OS X > Built-in optical TosLink digital output > Nova optical digital input 1
Optical input from the Airport Express did sound better than the optical feed straight from the Mac Pro's built-in optical output. Voices via the Airport Express appeared a bit further back. Cymbals via the AE were a bit harsh and somewhat unnatural but the decay was more appropriate than what I heard via the built-in optical output of the Mac Pro. Bass was a bit thin via the AE as well. The sound via the built-in Mac Pro optical output was better than the sound fed directly from the Mac Pro to the Nova via USB but not nearly as defined as the analog feed from the Proton. Bass via the built-in optical output was not real cohesive and was inconsistent lacking on some selections and a bit forward on others.
Note: I used the Airport Express digital feed into the Nova's optical input number 2. This input has been adjusted by Signal Path to be more tolerant of sources with higher than average jitter at the sacrifice of a little sound quality. Users previously had issues during playback via an AE until this adjustment was made. In addition not all versions of iTunes and not all versions of the Airport Express work the same. These differences lead to inconsistent results for those seeking to test this at home.
- Mac Pro OS X > USB > PS Audio DLIII > Analog RCA > Nova AUX1
- Mac Pro OS X > USB > Nova USB input
The Nova was sonically superior to the DLIII in every way via both components' USB inputs. The DLIII was not cohesive and sounded artificial. Compared to the Nova everything via the DLIII just sounded wrong. This could be partially due to the automatic upsampling to 24/96 that was done by the DLIII. I didn't try upsampling to 24/192 during this listening session. Via the DLIII to the Nova's analog inputs images were very smeared and voices were not crisp when they should have been. Voices even sounded nasally compared to the Nova.The DLIII's bass definition was less than all the other components and the overall sound was fatiguing and over-saturated. Listening through the Nova's internal upsampling compared to the external upsampling of the DLIII was much better sounding. Upsampling is not a matter of where it takes place. In this comparison the Nova's upsampling produced a much more cohesive sound when compared directly to the DLIII via USB inputs on both.
- Mac Pro OS X > USB > Benchmark DAC1 PRE > Analog RCA > Nova AUX2 & AUX3 Home Theater Bypass Mode
- Mac Pro OS X > USB > Nova USB input
Connected to the Nova's Auxiliary analog input 2 the DAC1 was set to calibrated mode via the switch on the rear of the DAC1. Calibrated mode bypasses the front panel volume control on the DAC1 for configurations like the one used here. The DAC1 PRE's bass was much tighter than the Nova's when USB inputs were used on both. Keep in mind the DAC1 PRE uses CEntrance code and the TAS1020B chipset for its USB input whereas the Nova does use a rather generic off-the-shelf USB implementation. Compared to the Nova this tight bass didn't have as much texture to it. It's hard to verify which sonic characteristic is the most accurate without hearing the mic feed at the recording. The DAC1 feeding the Nova produced vocals with pinpoint focus and revealing highs. Decay via the DAC1 PRE had a tad bit of overhang and appeared too bold for natural sounding decay. The Nova via direct USB input lacked air around the instruments that the DAC1 PRE displayed. The Nova's bass lacked the DAC1 PRE punch and instruments during complex passages all merged together much more so than the DAC1 PRE.
Following this configuration I flipped the rear switches on the DAC1 PRE and Nova to enable the DAC1's volume control and Home theater Bypass on the Nova. The HT Bypass feature allowed the DAC1 PRE to work as a preamp delivering an analog signal straight to the Nova's power amp. To use an over-generalization the vocals in this configuration sounded like they came out of a cave. The decay was still bold, unnatural, and seemed to hang on for dear life much longer than appropriate. To say it another way, the DAC1 PRE tends to memorialize some events. If it's possible to make a clear conclusion I think the Nova's preamp was a benefit to the sound of the DAC1 PRE. I much preferred the vocal performance via the DAC1 PRE when HT Bypass was disabled and the DAC1's volume control was bypassed feeding the Nova's preamp. In addition I preferred the coaxial input of the DAC1 PRE feeding the Nova's HT Bypass analog input over the previous USB based DAC1 connection. This was better sounding but still required the Nova's preamp section to bring out the best DAC1 PRE had to offer.
- Mac Pro Windows 7 > ASUS Xonar Essence STX > Coax S/PDIF > Nova coaxial digital input 1
- Mac Pro Windows 7 > ASUS Xonar Essence STX > Coax S/PDIF > Benchmark DAC1 PRE > Analog RCA > Nova AUX3 Home Theater Bypass Mode
The last configurations I tried used a Windows 7 64-bit based music server. The reason for the switch is the ASUS card does not work with Mac OS X at this time. I used J River Media Center v14 and WASAPI output in Exclusive Mode. I verified bit perfect digital output to the best of my ability via the HDCD illuminator on my Alpha DAC in addition to researching many different configuration options and their results on the bit stream output. The ASUS Xonar Essence STX PCIe audio card feeding the Nova via coaxial S/PDIF was clearly the best sound I received throughout The Nova Sessions. Again, the Nova in this configuration sounded better than all the other components and all the other configurations. The DAC1 PRE's USB input connected to the Nova's AUX2 analog input was a close second. During The Nova Sessions the tube section of the preamp was in use until the very end. With the tube disabled the bass had a bit more texture and the differentiation between bass notes was a tad better. Listening to John Mellencamp's Longest Days at 24/96 the Nova added a little gloss to the vocals that I hadn't heard elsewhere. I'm not a fan of additives in my music, but many readers may find this bit of added gloss pleasing in the short term. Using the ASUS Xonar Essence STX to feed the DAC1 PRE's coaxial input raised a bit of background noise not present when feeding the Nova directly or feeding the Nova via the DAC1 USB based configuration. This could be due to the preamp section or volume control of the DAC1 since the HT bypass only uses the Nova's amp bypassing it's DAC and preamp section. The pinpointed vocals heard via the DAC1's USB input were no longer present via coaxial S/PDIF. The overall sound was a bit sloppy compared to the DAC1's very good USB input.
Real Wrap Up
Once again the free flow of information and uncensored Computer Audiophile reader comments have lead to something good. I was called-out on a less than stellar review. After the initial shock I set out to work the Nova over like a speed bag to deliver actionable information and additional data points for the CA readers. The whole process involved pages of notes and a lot of listening to music. I couldn't be happier that the CA readers spoke up and pushed for better information. Bringing out my small arsenal of DACs for a comparison to the Nova was fun and informative. Another plus was Signal Path's David Solomon being open to and encouraging these comparisons. Not all manufactures will allow direct comparisons during reviews of their products. In typical Signal Path form David said, "Let the chips fall where they may." To recap my overall impression, the Nova sounded better than the other components and configurations using Windows 7, J River Media Center, WASAPI + Exclusive Mode, and ASUS Xonar Essence STX outputting bit perfect audio via coaxial S/PDIF to the Nova's coaxial input number one. The Benchmark DAC1 PRE using its USB input, feed by Mac OS X and iTunes, and outputting analog audio to the Nova's Auxiliary input number two was a close second place. The Wavelength Audio Proton is not a recommended combination with the Nova for reasons mentioned above. The Proton continues to be one of my favorite product of 2009 but there isn't any synergy with the Peachtree Nova. The PS Audio DLIII was out of its league during The Nova Sessions although it may perform better in other scenarios. I'd like to wrap things up by thanking the dedicated Computer Audiophile readers for providing constructive criticism that lead to the real completion of the Peachtree Audio Nova review.