Originally Posted by HeadphoneAddict
I have the CARAT-TOPAZ here and have spent about a week listening to it, and wanted to post my impressions here for you all. I GOT A LITTLE MORE LONG WINDED THAN I HAD PLANNED. I am not sure how many hours the CARAT-TOPAZ has but MoNelly put a few on it before I received it, and I added about 24 hours to it, mostly while listening to it. I figured if it had enough hours on it for him to review, then it was enough for me.
I used a variety of headphones, including HD600 and Grado RS-1 with APS v3 cable, ATH-ESW10JPN, Westone ES3X, Sennheiser IE8 and Phonak Audeo PFE. For my compact comparison rigs I picked ones with the best DAC inside, included my iBasso D10 with rolled opamps (AD743 + AD8616 buffers) which would cost about $365 after shipping and opamps, my Pico DAC/amp ($500), and my fresh new Pico DAC-only with RSA P-51 Mustang ($700 combined). Prior to the review my preference for listening to my Macbook has been the opamp rolled D10 and my new Pico DAC/P-51 Mustang, and feel both are excellent and on a similar level. In testing them as DACs with line-out I used them with my ALO Amphora amp which is very accurate, neutral, transparent and detailed - plus as a transportable amp it is easier to connect to a DAC with my Macbook than my other desktop amps.
In the first part of the review I look at the TOPAZ as a DAC/amp combo, and ignore the line-out which I tried later on. In my first half an hour with it on my Macbook via USB DAC I compared it to my D10 using my HD600. My initial impressions were that my opamp rolled D10 via USB has more detail, depth, space and refinement; while the CARAT-TOPAZ via USB is more forward and not quite as smooth. But the CARAT-TOPAZ was still fairly enjoyable sounding as a first impression.
I then switched the CARAT-TOPAZ to optical and the soundstage pulled back and was not as forward, which was a little creepy sounding to hear the instruments shift places to a different location with a change in the input. I kind got that Alfred Hitchcock "push/pull" sensation, but with sound instead of via camera. And in addition to it being more spacious and detailed via optical, it smoothed out a little more too - although it still did not sound as refined as my comparison rigs. Nevertheless, the optical input was a noticeable improvement to my ears and I would prefer to use the optical over USB every time when using it to listen to headphones. On the other hand, my iBasso D10 comparison rig (which has optical, coax and USB) is good enough to use it via USB anytime and not just when optical or coax is unavailable, even though its optical input also sounds slightly better than via its USB.
Once I determined the differences between using the optical input and the USB input, the remainder of the headphone amp testing was done via optical input. When comparing the headphone amp of the CARAT-TOPAZ vs the D10 with AD743 opamp and AD8616 in the buffers, the CARAT-TOPAZ doesn't seem as enjoyable as the iBasso D10, regardless of whether via USB or optical USB. And I get the same result when using the Pico DAC-only with the RSA P-51 Mustang, which also improves upon the CARAT-TOPAZ. The comparison rigs just have a better sense of musicality and transparency that is not often matched in portable rigs, and even rival some desktop rigs. While the CARAT-TOPAZ was enjoyable it was not as believable in the illusion of being there - it was more fun than real.
Regardless of the input, with the Grado RS-1 and Phonak PFE IEM I felt there was a slight harshness over the treble, sometimes even slightly brittle sounding, but not necessarily bright. The overall tone of the amp was still warm, and not thin or hollow. I was expecting the amp to sound this way with my Westone ES3X customs as well, but it was not - the sound was actually better with that combination and I was pleasantly surprised. And, the CARAT-TOPAZ was dead silent even with my 124 db/mw ES3X, and there was NO channel imbalance with IEM at very low settings on the volume control. (My Westone 3 and D2000 have been with a friend this week, so not tested).
Going back to the sound signature of the CARAT-TOPAZ - as described above it was vaguely reminiscent to me of the Vividaudiotech.com V1 portable DAC/amp. And I found, as with the V1, that I had to change the RS-1 pads from bowls to flats to bring the sound more in line with what I was expecting. With the Phonak PFE I already had the black filters in to smooth out the highs, and I had to switch from the silicone tips to the Complys foam tips to improve the sound with the CARAT-TOPAZ. After those changes, I was able to enjoy both the RS-1 and the Phonak with the CARAT-TOPAZ with noticeably less fatigue. I also retried the HD600 with the CARAT-TOPAZ to spend a bit more time with that combination, and I felt there was indeed better synergy there. With the HD600 the treble lost a good deal of it's harshness and I was able to forget about that and enjoy the music, just like with the V1. At this point despite the similar coloration, the CARAT-TOPAZ was definitely better than the $99 V1 as a DAC/amp. The Sennheiser IE8 always seems to have too much bass for me with most but not all amps, and the CARAT-TOPAZ was no exception (although IE8 do sound very good with the V1). I also was able to enjoy using the CARAT-TOPAZ amp with my ATH-ESW10JPN, and the amp did give them some improved oomph in the bass as well. Power output was also above that of my comparison rigs, and it never left me wishing for more whether 32 ohm Grado or 300 ohm Sennheiser.
As some of you may know, I have a fondness for portable DAC/amps which I have reviewed over the past year (I still have 9 of the 13 reviewed). Some are better than others and I have divided them into two tiers. The top tier amps were ones that presented a fuller weight to the instruments and deeper immersion into the performance and venue, with less colorations and better transparency (i.e. D10 stock or rolled opamps, Apogee Duet, Pico, HR Micro Stack, Predator, 3MOVE, XM5 stock or rolled, with the D3 straddling the fence). Within the top tier, they could also be divided up by the quality of their DAC section. The ones with the best DACs are the D10, Duet, Pico and Micro DAC, and over time as my tastes became more refined I have gravitated towards these for my listening (and I would put these DACs on a fairly equal SQ level as well). My second tier DAC/amps were those that didn't quite get me as deeply into the performance, or had some noticeable colorations, or were more picky about which headphones that they worked best with (i.e. D2 Boa, Nurforce Icon Mobile, Vivid V1). Lest you think I disliked the CARAT-TOPAZ with headphones, I want to reassure you that its sound is not bad, but it seems to straddle the fence between the two tiers as a DAC/headphone amp, like the iBasso D3 (of which they sound nothing alike, but I no longer have the D3 to compare). So, I would not rate the amp section badly, but I also do not rate it as highly as others.
Listening the the CARAT-TOPAZ as a DAC only, via RCA out into my ALO Amphora, my impressions are quite different from above. My first thought was, "Now we're talking". I was taken aback a little the first time I tried this, as I was originally guessing that the CARAT-TOPAZ was being held back by its DAC, and yet the USB DAC line-out was nothing like what I heard with the headphone out. With Philip Glass Portrait by Angèle Dubeau & La Pietà, the missing space, depth and instrument placement was there. There was an improved sense of emotion within various types of music genre, and I enjoyed the CARAT-TOPAZ as a DAC via USB or Optical, with most of the harshness of the headphone amp section removed from the equation. Several times I found myself listening through several songs in an album before realizing that I had forgotten about listening for the review. That says something right there about both the DAC and the Amphora. While I was able to enjoy the USB DAC line out much more this way, I still feel there is an improvement in texture, soundstage and detail with the Optical input.
With my comparison rigs - the Pico DAC-only has a USB DAC good enough to match any of my portable or compact optical DACs with 16/44.1 lossless music, and it seems to have more resolution than the Pico DAC/amp that I previously loved to use as a DAC/preamp to feed a larger amp. In this review I felt the Pico DAC-only USB to be slightly superior to the CARAT-TOPAZ USB DAC line-out in its sense of space and depth. Likewise the D10 USB line-out was also slightly better than the CARAT-TOPAZ's USB DAC in those same areas, but still slightly below the Pico DAC-only as well. Still, at one point I could not recall whether I was listening through the D10 or the CARAT-TOPAZ without looking. Between the Pico and the CARAT-TOPAZ, I could more easily identify whenever I was listening to the CARAT-TOPAZ due to its more forward sound signature, but the harshness was mostly gone and not useful in identifying it anymore.
Switching to optical input with the DACs where it is available, it was more difficult to tell much of a difference between any of these three as a DAC, except that The D10 line out volume is noticeably lower than the other two DACs. In order to match the volumes I had to set the Amphora to low gain with the Pico and CARAT-TOPAZ, but switch to high gain with the D10. Similarly, changing the D10 to use its headphone out as a preamp, in high gain at max volume it would match the output levels of the Pico DAC-only and CARAT-TOPAZ, with no degradation in sound quality.
In the end, I really liked the CARAT-TOPAZ as an Optical and USB DAC with line out, but less so as a headphone amplifier. However, with a DAC section at least on par with the $399 Headroom Micro DAC, for $50 more you get a headphone amp included (but no coax). So, in that light it isn't such a bad deal. If it was all I had I could still enjoy the headphone amp section, but I have other options to choose from that I would prefer more. Still, it's nice to have a headphone amp included in such a nice DAC, and I can see where this would be useful on the desk with a computer and limited desk space. If you needed a small DAC/amp for a computer rig, and wanted to listen to headphones now with plans to feed the signal into a full size amp later, I would also consider the iBasso D10, Apogee Duet, or Pico DAC-only with any decent amp.
I bet you could probably fit a Cavalli CTH right on top of the TOPAZ and have a great compact DAC/amp combo that way, and the extra $100 cost over the Pico DAC-only gets you a great optical input in addition to the USB. If you don't mind the issue with low output voltage from the D10's DAC, after you upgrade the opamps it is about the same price as the Pico DAC only, but the D10 includes optical/coax input and a great headphone amp on top of that. It's great to have so many choices.