Why standalone DACs and not pre/pros?

Just out of curiousity, it seems to be that most of the forum threads seem to be about standalone DACs, rather than more modern pre/pros that have DACs built right in, many of which can higher handle bitrates natively.

I'm not advocating one or the other, per se, but I'm just wondering why that seems to be the case.

Is it because most folks have a legacy all analog preamp they want to keep using?

Excellent topic watchnerd and one I'm glad you have raised. I'm guessing that a lot of the folks here (who know way more than I do) would argue that in general, but not always, most standalone DACs just do a better job and sound better than most DACs integrated in pre/pros or A/V processors. Plus I would guess that as you get into the really rare air of the audiophile world (say, systems in the 5 and 6 figure range), an insanely nice standalone DAC just can't be surpassed. I'm really interested in any discussion that takes place on this topic, because I am very happy with the sound of the pretty decent BB/TI DAC in my A/V processor that, according to the literature, will handle up to 24/192. The only thing I might do sometime down the road is audition something like the Pace Car or Digital Lens to see if I have any jitter issues coming from the toslink from my Macbook. But for now, as someone admittedly somewhere in the mid- to hi-fi range of things, I'm doing fine without the standalone DAC. As I said, great topic, and I'm looking forward to the discussion coming from all sides of this issue.

TheOtherTim

PS In defense of this forum and Chris, there have indeed been several threads involving people going without standalone DACs, but I would agree that the majority of posts seem to be as you mentioned.

Hi Guys - This is an interesting topic. I think the answer(s) to why people are choosing standalone DACs are the same as why people choose separate components (preamp / amp v. integrated).

In my system I go straight from my Berkeley Audio Design Alpha DAC to my amp. I think this is a fabulous way to go if one doesn't need analog inputs.

TheOtherTime, what AV processor are you using?

For the record, I just pre-ordered a Rotel RSP-1570 (not really on the market yet) pre/pro. My phase 1 plan is to go straight from a MacBook Pro and/or Airport Express into it. In theory, the spec sheet says it can handle up to 24/192 LPCM input.

I have no idea how this will sound.

From what I gather after reading most of the discussions it all relates to the type of connections. It seems stand alone DACs have a larger variety of inputs, that match with the outputs from a notebook or soundboard which are limited to what is common in the computer industry.

I've read debates on the virtues of USB 1.1, 2 and now the possibilities of version 3. Macbook users debating Firewire 400, 800, and TOSLINK. Sound cards with SPDIF coax. On and on, and I'm not the only one who is somewhat confused and undecided on the best direction.

Audio components like pre-pros, or an Integrated Amp with an internal DAC generally limit the inputs to TOSLINK, SPDIF, and sometimes balanced XLR.

At the CES show this year i asked at least six to eight reps the same basic question you have. Of course, each had a different scenario, and one attempted to explain using football metaphors. Here is what I gathered. There are a number of audiophiles sitting on expensive, but dated, CD/SACD/HDCD players. The digital to analog conversion chips and filters, and clocks, do not perform as well as current DACs. Then there are the multi disc players: HD-DVD/DVD/DVD-A/CD. No multi disc player can do everything well, those that come close are ultra expensive. Then there are the various music servers where people have downloaded everything from Redbook CDs to MP3 files.

The DAC (internal or stand alone) can, depending on the prerecorded source, compensate for the short comings with audio only.

It seems that the combination of up-sampling and over-sampling (if done just the right way) can yield a superior analog signal, with the side effect of eliminating jitter. However, as we all know, a poor recording is just a poor recording, and a DAC will only make it sound for the worse.

I've seen preamps with a bypass for DACs, so the signal connects directly to the power amplifier. My Bryston B-100DA SST integrated amp has an internal DAC with its own power supply and connects directly to the amp circuits. I'm sure there are other configurations. I just saw a german made DAC with all the latest conversion chips and filters delivering a super clean analog signal, only they added "tubes" to the analog output to create distortion. This is an emerging market, and everyone wants to build a better mousetrap.

Daphne

I use a stand-alone DAC because combo units often don't have USB connections, which is my preference. There are a few out there (Outlaw, Bel Canto), but they didn't fit my needs, so I went with a DAC + pre & power amp.

Watchnerd, my A/V processor is a Yamaha RX-V2700, purchased a year or two ago. Some would probably consider it mid-fi, but I like it a lot. The DAC chip inside is: http://focus.ti.com/lit/ds/symlink/dsd1791.pdf

The connectivity reasons cited by the last couple of posts are certainly valid. I mentioned my possibly auditioning a Pace Car or Digital Lens - a side benefit there is it gets me from toslink to coax.

I think I'm also understanding the argument of the worth of separate components to some, as Chris mentioned. By going with an all-in-one unit, you may be compromising on one or more of the pieces.

TheOtherTim

There are certainly compromises in some built-in DACs vs. standalone units, but they are often audibly insignificant. I've heard a couple of dozen different DACs or so, in different sources and stand alone (mostly studio stand alones). While there are differences, they are usually very small, the kind of stuff you have to actively, even intensely listen for.

In all my digital listening -- from upsampling DACs built into DVD players to iPods, to computers to CD players to several stand alone DACs, only one really stood out, and it did so not because it was undeniably superior, but because it was undeniably horrid. There was no mistaking it. Even audiophile DACs designed for "warm" "analog-like" sound don't sound much different. When you think about this, it makes perfect sense. The technology is mature and no self-respecting audio designer would create a DAC that was intentionally way off of a flat frequency response. They should, theoretically, all sound the same, because they're sources, not tone controls. And more often than not, they're pretty close.

I wouldn't worry about jitter, either. It can be reduced, and you can spend a lot of money doing so, but it's already well below what you can hear, so what's the point?

A really good stand alone DAC has separate paths for digital and analog signals, a better power supply, audiophile grade parts, etc. If you listen really, really closely to what your equipment is revealing when you should be grooving on tunes, you might even hear it.

Tim

Regarding optical vs USB vs Firewire, wouldn't it be simple just to use a hub that converted between the different connection types?

It would seem like one could make a box that has inputs on one side (optical, USB, Firewire, Coax, whatever), a large RAM buffer and a clocking chip, and outputs (optical, USB, Firewire, Coax, etc) on the other.

Then one could use whatever kind of processor one wanted, regardless of connection type.

Also, what's the advantage of Firewire or USB compared to optical?

In general, separate components are sonically superior and more expensive than the integrated counterpart. In addition, a unit that only does one thing is expected to be excellent compared to a unit that does many things. I believe one manufacturer refer to a Swiss army knife that is very useful and does many things but in no way compares to the dozen of specialty knives that it replaces. Integrated units will usually have more compromises in design and parts than a stand-alone unit.

One of my DACs for example is the Benchmark USB DAC1, which is an excellent stand-alone DAC by most people’s standards and is probably the most often referenced DAC that all other DACs are judged by or compared to. Benchmark Media recommends that users use the DAC1 optional volume control without a preamp since probably 80% of the time there will be a substantial improvement in sound quality. While this is true, there are many active and passive preamps that have significantly better volume attenuators, wiring and in the case of an active preamp, power units than the DAC1. Unfortunately excellent passives start at around $1K and excellent actives at around $3K. Add $200 to $1K more for excellent interconnects and it’s easy to see how the Benchmark recommendation is clearly the best cost effective solution, though may not be the sonically superior solution.

Another problem with combined units is redundancy. For example, I don’t want a source player with a volume control, a DAC with a volume control, an amp with a volume control and speakers with volume controls, especially if I have an excellent preamp solution or if I don’t need volume controls at all.

I can understand the logic behind the separates approach for old-school analog equipment like phono stages, but why for DACs?

DACs are basically computers. If we're comfortable using a computer (which is not a dedicated, single purpose device) as a front-end (the whole point of this website), why aren't we comfortable with a DAC being part of a multi-purpose device?

I also happen to think spending $200 - $1K on interconnects is, let's say, 'highly questionable' for most home audio applications.

One problem for now is to overcome prejudices. It might have been right in the past that separates outperformed integrates, but in my opinion that was just because the audio signal had to pass through a lot of analogue electronics in integrates, where the harm to the signal could be detrimental. In my kit most of the way for the signal is digital, so the signal can only profit from an integrated kit.

Theoretically, and boy is that an important word here, anything in the signal chain between the source and the amplifier adds noise and subtracts resolution (and it's a fine line between the two). Not so theoretically, every standalone DAC is also a preamp, because they contain an analog stage that brings the converted analog signal up to line level. So, theoretically again, the best solution is to go straight from DAC to amp, regardless of how esoteric your preamp might be.

Of course that means you'd only be able to use one (digital) source, you'd have no tone control and you'd be limited to the volume control on the DAC, which doesn't matter much because it is doing whatever damage it is doing anyway, unless your DAC has a switch that bypasses it, in which case the quality of the switch and its implementation enters the equation and becomes another potential problem.

Theoretically.

Theoretically, a bit-perfect software volume control, the simplest possible analog output stage in a DAC (no op amps, just a small output transformer, perhaps) and your amp of choice would be best. No, let me take that back. Theoretically, I have the best sitting here next to my desk: An all-digital receiver. No DAC at all. All of the processing, the entire signal path, from the moment the signal comes in the back, is zeros and ones, it is even amplified by Equibit digital amplifiers, the data isn't converted to voltage until the very last stage before it is put on the speaker terminals. There is zero opportunity to introduce noise or degrade resolution, and those are the ancient boogeymen of audio, the characters that have driven the attention to detail, short, simple signal chains and absurdly expensive parts in high-end components. And in this cheap Panasonic digital receiver, they are simply not an issue. They don't exist. Got good input and output jacks? We're done.

Theoretically.

Thing is, sitting right next to that Panasonic is a Harman Kardon integrated amp from the early 70s with more switches and buttons than a disco mixer, and on most recordings, I like the way it sounds better.

So much for theory.

Don't get me wrong. The Panasonic hits way above its weight. But there are times when the sloppy warmth of the old HK is just the deal.

If it sounds good it is good.

Tim

Great post Tim! I'll reiterate your last statement.

As we say frequently on CA, if it sounds good to you then it's good.

Thanks Chris. Apparently I think about this stuff too much. I suppose the ultimate example of "if it sounds good it is good" is tubes. Using tube pre and amplification with digital sources is SOOOOO counter-intuitive. But sometimes it sounds good.

Tim

I think hi fi enthusiasts are very conservative and deeply suspicious of change, so are naturally resistant the idea of integrating DACs with preamps and even power amps, instead they are inclined to believe they'll sound better in separate boxes. The reality is that these boxes often cost more than their contents and boy do they push prices up compared to an integrated solution.

Not only the price but also the sizes of modern electronic components have fallen dramatically over the years, so now it's possible to put as good a DAC as you can make and a preamplifier on a PCB not much larger than a playing card along with all the circuitry for remote control. Not only is there no sacrifice in sound quality, but there are significant advantages. The Pro Side has realised this and DACs like the excellent Edirol UA25 also incorporate A to Ds and Mike preamps.

The main problem facing stand alone DACs is that they tend to react differently to different amplifiers. This because they radiate a bit and they produce some hash above 20 kHz. Therefore you may buy a well reviewed one and be disappointed if it doesn't suit the rest of your system. In fact, if you think about it, since you can't individually audition all the separates in an Audiophile system, the chances of you picking the right bits and getting the best results are slim!

Ashley

Is sounding good really the goal of audiophile (computer or otherwise) music reproduction, or is the goal an accurate recreation of the original signal, whether that is pleasant sounding or not?

I'd say that one follows the other and that the best way to look at it is this; All hi fi is distorted and distortion is spoiling the sound. Some distortions are less offensive than others, but they are still distortion and need removing or reducing as the technology permits. I don't believe that any distortion is a pleasing benefit, though some manufacturers have tried to persuade us otherwise.

Therefore the least distorted system will get us closet to the original performance, assuming the recording engineer producer has done his job properly.

Ash

Unfortunately, Ashley, assuming the engineers/producers have done their jobs properly is a HUGE assumption and more often than not, there is no true original "performance" but a long series of performances patched together into a performance-like presentation. I'm not disagreeing with you. More often than not, the more accurate system is the better one in my view. But "what is accurate" is so nearly impossible to answer that, in the end, you just have to listen to what you like.

I think I'd like your powered monitors and sub. I wish I could find someplace to hear them.

Tim

"Is sounding good really the goal of audiophile (computer or otherwise) music reproduction, or is the goal an accurate recreation of the original signal, whether that is pleasant sounding or not?"

That's a great question / statement watchnerd. In my opinion it is a mix of both, but a slightly different goal.

My goal is enjoyment of music which can often be much improved through quality components. Accurate reproduction helps reach this goal much of the time. But there are also situations where accurate reproduction may decrease enjoyment. I don't think anyone wants to listen to a very accurate & expensive system that is fatiguing after ten minutes. Not that all very accurate systems are fatiguing, but with some types of music they may be. I think we should also keep in mind that everything is not black & white or mutually exclusive. The term audiophile is described by Wikipedia this way "Audiophiles try to listen to music at a quality level that is as close to the original performance as possible. They use high-fidelity components to try to attain these goals. Many are music lovers who are passionate about high-quality music reproduction."

Does this mean someone with my goals of enjoyment of music through accurate reproduction is not an audiophile? Some may think that. I think a laid back approach where there is some gray, not only black & white, is far more enjoyable and often involves the most accurate reproduction possible. Listening to the RR HRx recordings at 24/176.4 there is no doubt I want the most accurate system available.

I agree with Chris and I've been trying to wake up our US agent so you knew where he was!!

try www.overtureimports.com Tom Jankowski is the man and he'll be at the Rocky Mountain Audio Festival.

I'm trying to avoid reference to AVI products and discuss things in general terms so as not to take advantage of the hospitality afforded by Chris.

Ash

Sorry gentlemen, I should have explained my point with DAC connections in more detail.

TOSLINK: maximum run length using top quality quartz glass cable is good for about 3 to 4 meters, if you can find a cable that long. Plastic cable only has a bandwidth of 5 to 6 mHz, and 10 mHz bandwidth is needed to for higher sample rates of 24 bit and above. The bottleneck (so to say) is TOSLINK uses common red LEDs to transmit the signal, not lasers like in other forms of fiber cable formats.

SPDIF Coax digital cable: from what I hear, this cable is good for about 10 to 15 meters when transmitting a high bandwidth signal. The shorter, the better.

USB: short runs only on 1.1, however the max on USB 2 is about 5 meters, but 3 meters would be better.

So for all practical connections between computer and audio system one must place the computer in close proximity to the DAC. If your DAC is integral with your preamp, or integrated amp, the computer will need to be close to that component due to the limited choice of connections.

Wireless connections have their limitations also.

My point being, most broadband high speed digital audio connections (capable of transmitting a 24/196 signal) were designed for short distance. Sitting at your general purpose home computer 6 meters, or more, away from your audio system can pose "some" connection problems. Of course, there are options. That is what we discuss on this forum.

Daphne

Chris will correct me but optical digital cables can be very long indeed and we use 10 metre ones all the time. Any greater distance and most use Airport Express, which is a superb 16/44 streamer.

Ash

Ash, thanks for the US agent info. Unfortunately, he has no information on his web site other than that he carries your products. Then he links to your web site. No pricing information, even. It doesn't really matter. He's in Michigan. Nearly a thousand miles away. It won't help me hear your speakers. They inspire my interest because I've used active speaker, for both studio and performance, and they tend to sound very good.

Tim

Whatever we spend on audio components should be fully justified by thorough listening. In the old days we used to listen to components at our local dealer and then perhaps borrow the dealer equipment over the weekend when the store was closed. Nowadays the more likely scenario is that we demo audio equipment for 30-day trial evaluations from the manufacturer or distributor. The point is, no amount of reading or research is a substitute for listening to the audio component in your system and home setup. If the music through the changed component is significantly better and you feel that the investment is worth it, then buy the component. I also agree that spending $200 - $1K on interconnects is questionable for most home audio systems, but a high-end reference audio system is not your typical audio system.

I also feel that another advantage that separates has over integrated components is the possibility of piecemeal purchasing. When I add up the total costs for the top end reference music server posted on this site, it is over $15K (Mac Pro $10K, Lynx $700, Berkeley DAC $5K). Now we all know that I can buy a Mac Pro for less than $3K and upgrade later. I can buy the Lynx card now and a cheaper DAC now and buy the reference DAC later. Now suppose that an integrated CD player or music server was sonically superior and only $10K. The single purchase of an integrated component for $10K is so much harder for most of us than perhaps a $5K investment now that grows to $15K total later. Of course we know or claim that the sonically superior computer audio system costs far less than the sonically equivalent player.

The integrated component also locks us in to the component except for the possibility internal modifications. Whereas upgrading the Mac Pro or using a superior DAC or interface is relatively easy. Let me pick on Conrad Johnson or Audio Research since the equipment from these companies is widely known and highly respected. Would I ever want the Berkeley DAC integrated into the LP275M or Reference 210 amplifiers or in the ACT2 or Reference 3 preamplifiers? I don’t think so and I also happen to believe that there will be superior DACs than the Berkeley DAC for half the price 3 years from now. I don’t feel the same is true for the reference amps or preamps.

I also agree with tfarney that theoretically the best solution is to go straight from the DAC to the amp but few people have systems that can pull this off. The next best solution is usually a passive preamp that may work in many more systems but not all. Using an active preamp to get superior results is the most expensive solution but it will probably be more effective in solving other system ills not corrected elsewhere. In my case perhaps an alternative may be to mod the Benchmark USB DAC1 with the best volume attenuator and wiring to try to better the sonic quality over using my passive preamp but obviously there are no guarantees on the outcome. Again I would have to agree with Benchmark Media that for most people using the volume control on the DAC will be superior, but most is not all.