Eastern Electric Minimax BBA Buffer amp (mullard valves)
Ovation High Fidelity 1501/1701
Ovation Model 1721 Power Amplifier
DEAL OF THE DAY
High Fidelity Cables 1.5m spk cables
Scratch Building a Fender 5F1 Champ from Scrap Parts.....Part 2
Computer Audio Design CAD1543 DAC Review
My first review for the ‘wam puts me scarily close to breaking a personal rule of mine. When I’m approached by someone who has effectively brought a product to market single handed, I’m always nervous about being asked to review what is in effect their pride and joy. My crude scribbling could condemn their efforts to the bin and that isn’t really what I feel reviewing is about.
In this case, a quick back and forth between me and Scott Berry, the founder and head of Computer Audio Design, put some of the fears to bed. CAD is a small company but it has a focus and approach that lends credibility to what they are doing and as such, the 1543 DAC is something that warrants closer attention. What you see here is a product that is designed to fulfil a specific set of requirements with few preconceived ideas about how it should be done. The result is a product quite unlike anything else on the market.
How so? The 1543 is a USB DAC and by that I mean that the sum total of inputs is a single USB-B connection. This is an asynchronous design with full galvanic isolation from the connected device. In turn this sole USB outputs to a pair of RCA connections making the back panel of the 1543 unapologetically sparse. It is designed to offer the best method that CAD feels is possible to decode a USB signal from a computer and output it to an amplifier- nothing more, nothing less. There are other products that have a similarly tight design focus but nothing I’ve seen goes about decoding in the manner that the 1543 does.
Having extracted the signal from a computer using a USB connection that if not absolute state of the art (it won’t handle DSD or super high resolution for example although the design is such that CAD feels that future updates will be possible if required) is definitely contemporary, things take a more unusual turn. The 1543 is built around 16 TDA1543 DAC chips in a resistor ladder configuration which means that they generate an output of 1.65v without in turn needing a conventional output stage. Scott experimented with a variety of chipsets of varying vintages during the development of the DAC and the selection of this older design is based on the performance that resulted rather than a desire to put a ‘famous’ chipset in there. The DAC’s operate in stereo so all sixteen are in the ladder rather than eight a side.
This ladder operates without any form of oversampling or filtering. Like a number of other designers Scott feels that they cause as many problems as they solve (an approach I personally feel rather depends on what you are trying to do with the filter) and as a result the 1543 is decidedly minimalist in terms of how it goes about decoding. The CAD then subverts expectations again by being exclusively solid state- a pair of valves in the output being almost the expected finishing touch to a NOS DAC. That said valves or not, the 1543 runs pretty toasty in use. This is almost certainly down to the power supply arrangements. Five independent power supplies are fitted and these account for the rather impressive all up weight of the CAD as a unit. Depending on your views on posh cabling, the 1543 either calms or aggravates your mental health by having a high quality captive mains lead fitted whether you like it or not.
The really good news is that the 1543 manages to clothe all of this technology in a chassis that manages to feel special- something that small companies can often struggle to achieve. If you need your components to be made from inch thick sheets of depleted unobtainium, the acrylic chassis of the CAD might not be sufficiently exciting to part you with your hard earned but the casework is non magnetic and finished to a very high standard. Technically the white unit supplied for review is a prototype but the fit and finish is really very good indeed. The acrylic is machine finished by a UK contractor and is completely free of any imperfections or rough edges. The only visible fixings are on the rear panel which gives the CAD a slightly TRONesque appearance- for me this is a good thing but your mileage may vary. Black is also available.
The only part of the exterior I’m not completely convinced by is the feet. Apparently, these are a ‘visco elastic polymer’ and I’m sure they do what they are designed to do but they ultimately feel like a cookie cut out of a memory foam mattress. They are not attached to the chassis and give the CAD a slightly irregular appearance unless you set about measuring the placement to ensure they are equal. Even if CAD fitted a ‘lip’ on the underside to conceal the feet rather than deciding to physically attach them, this might look a bit better than the current arrangement.
For the review, the CAD was supplied with a supporting ecosystem of components including an Asus laptop running Windows 7 and JRiver and an external hard drive of AIFF files being powered by a custom off board power supply which I made use of for the bulk of listening. I also substituted my own venerable laptop running Songbird and FLAC to make sure that the performance was reasonably consistent. It is worth noting that included in the asking price of the CAD is the support and expertise of Scott in getting the best from the partnering equipment. The DAC has been trialled extensively with Windows, OSX and Linux and he should be able to obtain good results with a variety of hardware. Partnering equipment was my standard pairing of Naim Supernait and Neat Momentum speakers- a duo that while collectively cheaper than the CAD, are revealing enough to give me a handle on performance.
Sonically, the CAD was left to its own devices for a day or so as per Scott’s instructions while I ploughed through a mountain of headphones and went to attend the press launch of another pair of the things. As such, it was a few days later that I sat down to listen to the CAD in earnest. I wasn’t entirely sure what to expect from a DAC that has a design philosophy that is subtly different from anything else I’ve ever reviewed but after an hour or two, it was making more sense and has continued to do ever since.
What the 1543 offers is a performance that is wonderfully understated. Nothing leaps out of the mix because the response is exceptionally even from top to bottom- something I haven’t always found to be the case with filterless digital in the past. It manages to be rich and detailed with a large variety of music but avoids lapsing into sounding overblown or unnatural at the same time. This is a neat balancing act and one that appealed more the longer I listened. Compared to the tonally dark but slightly unmerciful Naim ND5XS/XP5XS that I regularly use, the CAD finds the quality in recordings but when the material is less than pristine manages to avoid bringing out the worst in it.
Quite how it does this is something I’ve no firm hold on but I think part of it stems from the use of a 16 bit ‘CD’ chipset in the design. The result with 44.1kHz material is encouragingly ‘right’ in a way that some high res capable devices don’t always seem to achieve. The payoff to this is that the CAD treats everything as a 16 bit signal whether it is or not and while it still sounded pretty smart with high resolution material, did have to give some ground to some other designs I have listened to in the past. Given that so much of our digital for now and the foreseeable future is going to be 16/44.1, I think this is a solid enough decision to take, especially given how good the CAD is used this way.
The behaviour of the CAD is free from the negative connotations you might have with digital but this doesn’t mean that it shamelessly apes a turntable. It simply sounds clean, natural and entirely unfatiguing. It has impressively detailed and clean bass that- as with everything else it does- is integrated well with the rest of the frequency response. It would be logical to try and make some comparisons with the Audio Note CD 4.1x that passed through recently. The CAD is leaner and doesn’t have the bass extension that the 4.1 did but the frequency response as a whole is smoother and more cohesive and the top end is definitely cleaner. The lower output voltage is quite useful in this instance as it allows for the amp to be run a bit higher than is the case with redbook which seems to help matters too although if you are already low on gain, it will be less appealing.
Scott feels that there is a meaningful difference between AIFF as a compression type and FLAC (which I habitually use). After running some of my own music collection both on the supplied laptop and my own, there might be something to this. Conveniently, he supplied a copy of Admiral Fallow’s Boots met my Face in AIFF which I already have as FLAC ripped from CD. The CAD seemed fractionally cleaner and livelier with the AIFF copy via both JRiver and Songbird and whether this comes down to the ripping or whether the CAD genuinely prefers AIFF is something I am sure people can argue about for some time to come. If I were setting out on the process of ripping a library from scratch for the 1543, I’d choose AIFF to keep the voices in my head from taking over the asylum.
Ultimately, a degree of subjectivity will apply to any digital product at this lofty price point. As a lay member of the church of Salisbury, I confess that the really deep, chest thumping bass that the streamer generates is missing from the CAD which doesn’t go quite as deep. I also found that very top end of the frequency response is not quite as open and spacious as the rest of the frequency range but this is nitpicking and a speaker with a more explicit top end than the Neats would probably correct this.
The other criticism of the CAD is not really a problem with the DAC but one I have with the computer/DAC concept as a whole. The 1543 is fanless and the carefully selected power supplies ensure that it is absolutely silent in use. The partnering computer and drive were not however. I have no doubt that you can build a computer that is just as stealthy but you are in effect solving a problem that doesn’t exist for streamers (or CD for that matter). My NAS drive is noisier than the computer that Scott supplied for the review but it is 24 feet from the Streamer and thus completely inaudible. The CAD is not a cheap product and to truly do it justice, the costs won’t end with buying it.
This should not detract too strongly from the DAC itself though. This is a product from a small company that has set out with absolute focus to achieve one thing and- for me at least- they have to be judged as succeeding absolutely. If you are still reading this, you will already know if this product is applicable to you because for anyone using a streamer or will have their CD collection prised from your cold, dead hands, this is the bicycle your fish has always wanted. If you do use a computer as your digital source though and you are looking for a truly great partner, this is a product that needs to be listened to. The way it goes about the business of making music is something that only a very small number of digital sources can do and few of those are so perfectly designed to play nice with your computer. The 1543 is a niche product but it fills that niche with an assurance that means it will take some beating.
Discuss the review here
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