Twisted Pear Audio Opus
The second of our picks comes from Twisted Pear Audio's Opus DAC. Twisted Pear Audio is the collaborative effort of Russ White and Brian Donegan, who are both capable engineers and audio enthusiasts. The benefit of this teaming is that we find a number of kits ranging from volume control, selection controllers, DACs, voltage regulators, and even amplifier modules based upon some of the latest technology and at prices that blow the world of high-end audio wide open.
The Opus is based on Wolfson's WM8741, a differential voltage output DAC that supports up to 24-bit 192KHz resolution (source permitting). Dedicated output stages and power supply kits are available from Twisted Pear, designed from the ground up to compliment the Opus DAC. For those of you wishing to drive into single ended inputs on your preamps or amplifiers, the Ballsie converter/buffer module is the way to go. Total price including the Ballsie modules will range from $200~$350, on par with the price range of Doede's kits mentioned earlier. The Opus is available in a variety of configurations, from a bare PCB to a fully soldered and ready to go kit. There are no components to solder in any of the full kit format options, apart from the input/output terminal blocks depending upon individual configuration requirements.
USB to I2S input modules are also available, although Twisted Pear's design powers the PCM2707 from the USB bus. An asynchronous clock module is available that allows the I2S stream to be re-clocked, thus lowering jitter to aid high fidelity audio reproduction. Another option, rather than using the USB to I2S converter, is to opt for the MUX receiver module. Up to four S/PDIF inputs can be connected while a control switch allows you to select the preferred input. The MUX module is capable of outputting 24-bit PCM in I2S format for those who wish to playback recordings of this resolution.
I decided to use the Doede USB converter and go with a dual differential Opus DAC configuration requiring two PCBs both switched to mono mode supporting stereo left and right respectively. In my case, audio output feeds into a 3A5 dual triode per channel, followed by a Sowter 8650a balanced to a single ended 9:1 ratio output transformer. This is probably not a setup that will appeal to those immersed in the merits of signal to noise ratios and accurate square waves, but it's a solution that sounds very appealing to my less than golden ears.
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mindless1 - Monday, December 1, 2008 - link
The fact is, even audio streams that measure the same can and do still sound different. The problem is the resolution of measurement and the misconceived notion that the brain interprets sound at a fixed interval as measured.There's a lot of snake oil in the audiophile world, but there's also a lot of what you'd like to call "magic" only be cause you don't accept it as non-magic.
Any decent DAC would in idealized theory be as good, but in practice a different IC topology may lend itself better to certain inherant localized noise frequencies and cutoffs, be better mated to the circuit it's dropped into, have drifts from thermal changes, etc. If they were all the same why would there be so many? I will agree that which modern DAC is used in a reasonably good design matters less than what follows after it in the chain but the best way to minimize any potential for degradation is to start out with what is most likely to minimize it in every way possible then following this concept the entire time, waiting and seeing if the end result is audibly different rather than downplaying them all without knowing the additive result yet.
CSMR - Monday, December 1, 2008 - link
Yes if you are maximizing quality you will choose the best of all components. But it's more sensible to care about cost and time too, so you have to prioritize. The value of the research about the unimportance of DACs (at at beyond a certain level) is that you can stop worrying about this part of the chain and spend you time/money where it is important.JonnyDough - Tuesday, December 2, 2008 - link
Exactly my point. Why spend more on one component if it's going to be "bottlenecked" by another one. Spending $2000 on a nice amp is crazy if your other components are crap. I think in the end it's like all other techs. You want decent stuff for a reasonable price unless you have more money than brains. While I scoff at people willing to spend more than few thousand on a sound system, without them we wouldn't have gotten to where we are today - with good possibilities on the market. As long as you like what you hear, who cares if it's perfect? At one point is something "good enough?" I mean honestly, there are people starving in the world, friends dying of cancer, etc...and we want to worry about whether or not something is inaudibly "perfect." Blow your money on something that MATTERS, you can't listen to music every hour of everyday unless your job is singing.CSMR - Tuesday, December 2, 2008 - link
I meant you can spend time/money on speakers/room acoustics/dsp but food for starving people is admittedly a better use of time and money.JonnyDough - Wednesday, December 3, 2008 - link
That's actually a matter of perspective. For example, you can donate food to a starving kid in some third world country and next thing you know that child has three kids and no way to feed them - and you've just marginally made the problem worse, not better.I think money is better spent on education, which leads to fewer babies. Many countries do not have quality farmland that can support the population on their own (the U.S. supports a large percentage of the world's population). Then there's natural habitat destruction, pollution from oil for having to ship food to them, etc. You get the picture.
JonnyDough - Monday, December 1, 2008 - link
While I was generally agreeing with CMSR above, I guess what everyone ends up saying is that hearing is subjective, which is something audiophiles are always agreeing upon yet they still love to argue over things.Does a vinyl record produce better sound than a CD?
It depends on what an individual values most.
A CD may produce less static noise, but have a "duller" sound, seemingly less highs and lows. It all depends on what one appreciates with their own ears.
While there are measurements that can be taken in a closed chamber, one sound system might actually sound better in a specific home or room than another for whatever reason. Even so, the average person can rarely tell a difference these days between the moderately priced components.
The really silly thing is that people will spend $200 on a sound card and then use cheap plastic speakers.
Rajinder Gill - Monday, December 1, 2008 - link
Lol, it's ok, everyone in entitled to have their say.It's the first piece so bear with us while we try to cater to a wider set of ideals.
With regards to the obj/subj stuff, it's an argument that'll never be solved.
later
CSMR - Monday, December 1, 2008 - link
Sorry if I came on too strongly; I was just expecting that Anandtech would have not necessarily an expert take but at least a more technical take than you get in audiophile communities.I would do some more fundamental thinking about what are the key factors in computer audio playback.
As a start you could rank in terms of what is most critical:
computer performance, computer quietness, software (drivers, dsp), analog line out, volume control, amplification, cables, speakers, room acoustics.
I won't give you my list but you should think about it and it is possible to compare many of these things in a very quantitative way, and some are more important than others by several orders of magnitude.
AnnihilatorX - Monday, December 1, 2008 - link
A dumb question about correction.The theory behind it is simple enough, but why do we need dedicated hardware to do the correction? Why can't we use simple graphical equalizers? I understand graphical equalizers are quite discrete in the range of selectable frequencies. How much difference does it make?
Rajinder Gill - Monday, December 1, 2008 - link
DRC - ease of use and range of control, plus taking care of things in the digital realm rather than in the analogue.You could fudge some control with a multi band digital equaliser and the means to measure the response, but it'd be damn tedious and utimately limited.