Preamps built Into DACs


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A lot of higher end preamps are also DACs. A lot of guys that buy these high end DACs already have a high-end preamp.

How much money could be saved on a $6k preamp/DAC if the preamp section was removed? In my case, a preamp on a DAC is redundant. I believe the preamp section should be an option on a DAC.

What say you?
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128x128mitch4t
Agree. Only works with the same observer listening on two different systems. Even then I think the experiment is flawed because you could have a system that simply is more clear in the frequency range of human voice, which could be happen with boor bass response. for example on a set of electrostats with poor low frequency response this may be easier than on a true full range system.

Nonetheless, just for kicks, I'd be happy to try. If you set up a file transfer (you have my email), I'll give it a shot. Keep in mind I am not a native English speaker though!
Understanding lyrics is a particular type of human skill. Some people are just better at it than others. Seems like an extremely poor way of testing how resolving a system is.
Ed - I think this is possible. I have some old tracks that recently I noticed new lyrics and background singers that I never heard before. The challenge will be to distinguish the lyrics and understand them.

Steve N.
Empirical Audio
Steve, how would that work? You could get me a "live in the bluenote recording" and see if I can hear what table three was ordering on track 5 at 3 minutes 12 seconds into the track (two dry martinis)? Would be interesting, but not methdologically sound, because it does not account for difference in sensitivity of the hearing of the observer. One of us may simply have better hearing.
Ed - I'm sure your system is resolving. You may have one of the few.

Maybe we should exchange some tracks and find out how resolving.

Steve N.
Empirical Audio
Mapman - sure, my system comprises:

2009 Mac Mini with SSD and 8Gbytes DRAM (better than newer versions IME). Amarra rev 4318 used for playback - 3 EQs are used in Amarra to flatten the speakers and room. Tuned with calibrated mic Earthworks M30 and iTunes Audiotools. Music Files are all .wav format uncompressed.

16-foot Polestar USB cable

Short-Block USB cable filter

Empirical Audio Overdrive SE DAC - used for volume control and D/A

Empirical balanced "bare-wire" silver cables

Empirical Audio Final Drive transformer buffer for galvanic isolation and achieving true-balanced signals (2 chassis). Also switches in the Home Theater

More Empirical balanced "bare-wire" silver cables

Empirical Audio modded Parasound JC-1 monoblocks - power cables are top of line silver Tekline.com

Empirical Audio Clarity7 speaker cables

Custom 4-foot ribbon speakers with 10" bass-box underneath. Custom crossover with Jensen Capacitors air-core inductors, V-Cap Teflons, non-polar Black Gates and low-inductance planar resistors. All wired with silver-plated copper wire in multiple twisted-pairs.

I also have a Sonos connected with cheap S/PDIF cable to an Empirical Audio Synchro-Mesh reclocker that feeds the S/PDIF input on the Overdrive DAC for more casual listening.

I dont sell the cables anymore BTW.

Steve N.
Steve, you may have better ears than me (very possible), but I doubt your system is more resolving. I use your offramp 5 with monolith, the EMM labs DAC2X (used in professional studios) and the same speakers the guy that does HD remastering for HD tracks uses in his studio.
The chief designer at Bel Canto send me a one pager explaining the merits of digital volume control, and how unless you have very high sensitivity speakers (horns) and needs very high attenuation, there is absolutely no loss in a digital VC. If their VC was analog he would not be passing out such information.
Steve,

I have no doubt your system is ultra resolving.

Can you tell me what it is, out of curiosity?

Thanks.
"the reviewer preferred Bel Canto, which has Digital VC"

I read this review. I think the digital volume they are talking about is a digitally controlled analog volume chip. I dont believe it is DSP. They also used a certain low-jitter USB to SPDIF converter to drive the DAC BTW.

Steve N.
Empirical Audio
Mapman - Look, I have used a few digital volume controls, including the one in the DEQX, iTunes and Amarra. By far, Amarra is the best sounding volume software so far, and it starts to affect the SQ at more than -9dB. I can hear this because I have on of the most resolving systems on the planet. I clearly hear lyrics in tracks that noone else can make-out.

In most peoples systems they will probably not hear this effect until maybe -20 dB or more. This is due to the fact that there is so much other noise, distortion and compression in the typical system that these effects are masked. This masking can be caused by jitter from the source, active preamps and even poor amplifiers.

Steve N.
Empirical Audio
"The besst overall solution is to use a good volume system to reduce the volume to listening levels and then adjust finely for each track using -0 to -9dB of digital volume. Works like a champ."

I agree this is probably the best strategy in most cases today.

I try to keep the volume control on my Squeezebox Touch controls at max normally, then set my preamp volume to desired volume level for most tracks. Then I use the TOuch VC if needed to lower the volume a touch if needed from there, especially for louder recorded tracks. A bonus with a device like SB Touch is that remotes, computers, tablets, handhelds or any wireless device with a web browser can be used to tweak the volume down on the Touch from anywhere in the house as needed.
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After reading all of the above, the high end tube preamp is the way to go for me. In five years as digital technology continues to evolve, I'll revisit the feasibility of using the preamp section of a DAC.
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Agree again. At the end of the day, all designs involve compromise. I don't really care if a VC is digital, analog, or hybrid, but just how it sounds. It stands to reason that with the advances in digital technology the gap has narrowed, and DCS digital VC in their 100K DAC suggest when you pull out all the stops, a digital VC can be superior or equivalent to the best that can be achieved analog. This is encouraging because digital technology tends to trickle down very fast. But again, the proof is in the hearing. FWIW, in the Stereophile review, out of the DCS debussy, Weiss 202 and Bel Canto 3.5, the reviewer preferred Bel Canto, which has Digital VC (the Weiss has not). The reviewer never even mentioned it - just reported what he was hearing.
"I am currently using the digital VC in my Trinnov processor, and according to the manufacturer at 50db attenutation I am losing information."

Isn't loss of information a gradual thing with any volume control as the signal is attenuated? I don't think it just suddenly happens at some point. Attenuation might occur at different frequencies at slightly different rates for example with an analog control.

However each volume control, analog or digital might attenuate the signal slightly differently at each step, so no two necessarily are created equal. I would expect digital attenuation done right to be as good or perhaps even superior in terms of linearity and presenting what can be presented at any particular volume well.

Again, I suspect that this is another case where digital gets a bad rap categorically for no good reason. There has to be both good and bad digital and analog volume controls. ANy company that cares about good digital sound quality should be able to do it both well and in an affordable manner these days based on available technology. The technical challenge of implementing a good digital volume control algorithm would seem to be trivial compared say to the challenges of managing jitter as needed in real time during playback, IMHO.
Tru. I don't think all digital VC are created equal, and if someone sells a 100K dac with digital VC, they probably cracked the code on how to do it without losing reslution (or the minimal loss ofsets the loss incurred with analog VC). I mentioned the 64 bit megabucks Da Vinci and Totaldac, that also do digital VC.

This is important to me because I own the EMM Labs DAC2X, which currently has not VC, but its architecture allows for implementing digital VC through firmware. I am hopefull Ed Meitner joins the ranks of the digital VC done right crowd and delivers a stellar digital VC.

I am currently using the digital VC in my Trinnov processor, and according to the manufacturer at 50db attenutation I am losing information. Of course, this has not stopped them for using the exact same digital VC in the $40K ADA Reference SSP, so it can't be all that bad.
".....Well even the best S/W DSP volume controls seem to cause audible artifacts at more than about -9dB of volume reduction. No amount of dithering and resampling will help IMO....

There is absoltely no consensus on this, nor confirmation in listening tests. Lots of digital guru's will tell you -25db is fine. My personal experience confirms this."

I have a background implementing dithering and resampling algorithms for image processing applications used by the government and military. Not sure about this statement either. I would expect different yet comparable results in terms of accuracy to the alternative of not using digital if done well. Of course, that's always the big if with anything.

Also, the algorithms needed to accomplish optimal results have been well documented in academia for decades already and are old hat in the image processing world. I have no idea why it need cost a fortune to implement decent software based dithering and resampling to lower volume in home audio gear these days. That's why I like to buy gear that likes to advertise how their gear achieves performance, not just the claimed results. Then one can really know the value of what they buy if they care enough to do the homework.

In the case of DCS, specifically the newer more mega buck than ever Debussy gear, theirs is seemingly some of the most sophisticated home digital audio processing gear and software out there from what I read (with sound quality to match bsed on actual audition) but it comes for a hefty price. I would expect a very good perhaps reference implementation there that noone could fault based on technical approach nor listening.
Seems like an excellent approach. However, I believe going from 4.0v to 1.0v represents about 15db attenuation. Most listening takes place in the -20db -40db attenuation range (if you have sensitive speakers could go all thw way up to -60db), so the Wadia would still have to apply at least -25db attenuation in the digital domain, far more than -9db. It seems like the adjustment to output level are to adjust for speakers sensitive during initial setup. These sensitivies have indeed a range of about 15db. The for day to day listening you do digital domain volume control in the -30db - 0db attenuation range.
I note the following from the manual of my Wadia 121, which uses digital VC:

"Best performance is obtained when operating the Wadia 121Decoding Computer Volume Control near the top of its range. If needed, the maximum output level of your Wadia 121Decoding Computer can be adjusted to match the overall sensitivity of your system so that critical listening will take place with the volume control operating near the top of its range. Critical listening should be done when the 4th or higher LED is lit. The maximum out level of the Wadia 121Decoding Computer is adjustable by means of a series of IR commands issued from the Wadia remote control. The Wadia 121Decoding Computer output level is factory set to accommodate the most common range of system sensitivity. If you find that your typical volume level during critical listening is below the 3rd LED on the LED display, it will be advantageous to use a different setting."

The output levels can be adjusted to 4.0v, 2.0v, and1.0v.

This seems to support Steve's statement that "even the best S/W DSP volume controls seem to cause audible artifacts at more than about -9dB of volume reduction." I wonder how he feels about Wadia's approach to allow the user to adjust the output voltage. Since my understanding of electronics is so poor, I won't pretend I understand all of this.
.....Well even the best S/W DSP volume controls seem to cause audible artifacts at more than about -9dB of volume reduction. No amount of dithering and resampling will help IMO....

There is absoltely no consensus on this, nor confirmation in listening tests. Lots of digital guru's will tell you -25db is fine. My personal experience confirms this.

....The besst overall solution is to use a good volume system to reduce the volume to listening levels and then adjust finely for each track using -0 to -9dB of digital volume. Works like a champ....

In principle this seems like a very good approach. I personally would think a 0db, -10db, -20db -30db -40db analog domain attenuation switch and an additional 25db to work with in digital domain during operations would work just as well, but we're splitting hairs.
.... I believe it was probably abandoned because it is very difficult to implement. It puts another layer of complexity and linearity concerns on top of the architecture....

The worlds #1 manufacturer of cost no object DACs just released a >$100K DAC, but they abandoned the optimal implementation of the VC they used in earlier models and reverted an approach that compromises sound quality because doing it right is "very difficult to implement". Not a very plausible explaination
"However, my ears are telling me otherwise now, and the fact that a number of >$20 DACs use them suggest they can't be all that bad."

Well even the best S/W DSP volume controls seem to cause audible artifacts at more than about -9dB of volume reduction. No amount of dithering and resampling will help IMO.

The besst overall solution is to use a good volume system to reduce the volume to listening levels and then adjust finely for each track using -0 to -9dB of digital volume. Works like a champ.

Steve N.
Empirical Audio
"Steve, DCS latest gear has an all digital VC. Why would they have moved to all digital if they had a better mousetrap before?"

I believe it was probably abandoned because it is very difficult to implement. It puts another layer of complexity and linearity concerns on top of the architecture.

It has some limitations, such as no ability to go to zero volume. It can go really low, but not zero typically. I dont see this as an issue.

Steve N.
Empirical Audio
Hi Edorr,
You`re very satisfied with your current setup, you may not need a preamp for your needs.
I `ve own my Coincident linestage and their 300b SET amplifier for over 3 years. I plan to keep both for many years to come.The funny thing is my genuine admiration for both 'continues' to increase. I`m fortunate(lucky?) as they`ve led me to pure emotional involvement and musical bliss.
Best Regards,
Charles. Fair enough. With the lineup of DACs your listing I can't say you have been skimping on hardware. You got me tempted to try to insert a preamp and give it another try.

Thankfully I don't have any rackspace :) left. Do you still own the Coincident preamp?
Hi Edorr,
I get your point, of the examples you list I`ve heard theWeiss, MSB(diamond stack and fremto clock) and the DCS in direct mode to an amplifier. They just did`nt get it done for me. That`s why I `m not saying you`re wrong but you know what,we just likely hear things differently.

The different make up of our systems is a reflection of how we hear and are drawn to. Not better vs worse just different perspectives.
I don`t feel an aligiance to tube preamps and thus unwilling to embrace the new,not at all.New does`nt always equal improved or better, sometimes it`s just new.

If I ever hear a DAC/VC combination that sounds better I`ll readily admit it, all I want is pure, natural sound and realism in my system.Which ever technology does it best to my ears then that`s the direction I`ll follow.If I find a DAC/VC unit that provides the realistic organic tonality,body and 'breath of life-vitality' that I have with my current preamp I`d gladly jump ship.It has`nt happened so far.
Regards,
They are equally troubling in my mind, and for this reason I have been avoiding them like the plague. However, my ears are telling me otherwise now, and the fact that a number of >$20 DACs use them suggest they can't be all that bad. It is conceivable an well implemented analog VC will elevate performance of such ultra expensive DACs even higher.
Steve, DCS latest gear has an all digital VC. Why would they have moved to all digital if they had a better mousetrap before? Given that their latest "stack" sells for over $100K I can harldy imagine they did this to save cost.

I have a hunch the latest digital technology allows for the design of a digital VC without any loss of resolution, while avoiding the signal degradation of doing anything in the analog domain. There is a guy in France that build the 64 bit TotalDac, that tried every VC implementation under the sun and settled for a digital VC. The 20K light harmonic Da Vinci is also a 64 bit all digital VC.
Mapman - there are only two DACs that I know of that use the reference voltage to control volume (which actually connects the DAC line-out directly to the amps):

Empirical Audio Overdrive SE

I believe the other is a dCS DAC that is out of production

Steve N.
Empirical Audio
Keep in mind the VC is only part of the design. You never listen to just the VC. There are very good DACs with analog, digital and hybrid VCs. It is conceivable a very good dac that has a digital VC could be improved upon by making it hybrid or analog, but at the end of the day you are buying a DAC/VC package and system performance matters. Also keep in mind some DACs are now 64 bit, theoretically making it possible to control volume in the entire range digitally without any loss.

Some examples:
Hybrid: Weiss (and probably Steve's Overdrive)
Analog: Aesthetix, MSB, Theta
Digital: Bel Canto, PS audio, Berkeley, DCS
"However for well-designed DACs with volume controls, even these will be crushed. There are only a couple out there that accomplish this BTW, so it is likely that you have not heard them."

Steve, please list or reference if you have already.

Thanks.
" All the available musical information is encoded in the digital signal. This includes all the timbre, body, spacial information, decay and what have you. "

I agree with this and part of why I think the potential for pure digital amps is huge even with audiophiles and that these will be the norm in 5-10 years perhaps.
Here is one way of looking at it. All the available musical information is encoded in the digital signal. This includes all the timbre, body, spacial information, decay and what have you.

The DAC converts this digital information to an analog signal. Anything added to the analog signal after it leaves the DAC is by definition information that was not originally there.

In many instances what is added may make the sound more pleasing. It may compensate for something your DAC did not retrieve, or your speakers or amps do not reproduce naturally.

The better your system is capable of reproducing the sound encoded in the original digital signal, the less it will benefit from adding something in the chain that adds coloration. In a (hypothetical) "perfect" system a volume control that just controls volume will sound best.

A perfect source (say a live acoustic piano recital) will sound better live than running the same hypothetical perfect source signal into an (imperfect) preamp into hypothetical perfect (i.e. capable of perfect reproduction of the source signal) amps and speakers. QED
"It makes a lot of sense to bundle preamp and dac these days much like pre-amp and phono pre-amp have been bundled into some pre-amps for years. The fact is digital is the norm now, not phono. So it is a natural thing to do. May not be the best/right solution for all. THat is why there are still separates for purists who care, like me."

The distinction that needs to me made is between the DACs that just add a simple volume control in order to add the feature, and others that actually improve upon existing volume control technologies by using the infrastructure only available in a DAC.

Like so many preamps, active and passive, the devil is in the details.

Steve N.
Empirical Audio
"Even if you choose to go "no preamp"... there is still a preamp involved!! It's just a lower quality preamp, tagged onto the digital circuitry, sharing the same power supply as the digital section. No thanks!"

This is where you are dead wrong. You evidently missed some of my posts. There is actually "no preamp".

Steve N.
"So far in my listening experiences premium quality tube preamps are an asset and clearly improve the sound quality."

I agree. For MOST systems, the tube pre is an improvement. However for well-designed DACs with volume controls, even these will be crushed. There are only a couple out there that accomplish this BTW, so it is likely that you have not heard them.

Steve N.
Empirical Audio
"It just so happens, my current system (with digital volume control), give me a more body, tone and dynamics than anyting I have ever owned, tubes included. We have the same destination, but just get there with different technology. "

Myself, I would like to, and at this point feel pretty confident that I could, drop my tube pre-amp for a good SS replacement and still get the body, tone dynamics etc. I want. The reason would be to not have to deal with tube maintenance and replacement periodically, which is not cheap to do right. I have dabbled with tube and SS DAC (and pre-amp) options to date for example and that experience builds my confidence that either technology can work best. The devil is always in the details, which device specifically, how well does it mesh with the rest of the gear, etc.
Charles, you are making the incorrect assumption that my current preference to take the (tube) preamp out of the chain is motivated by different preferance in sound (i.e. clean versus full bodied). I thinkg we both strive to recreate the experience of the live event - this has always been my reference.

I have been using tubes and preamps all my life (I have owned Cary 300B, Graaf OTL, Rogue preamp, Audiologic Tube DAC, Modwright preamp). I did not all of a sudden change my preference from "body, tone and dynamics", to a "clean" digital sound. For years, I made the same choice as you.

It just so happens, my current system (with digital volume control), give me a more body, tone and dynamics than anyting I have ever owned, tubes included. We have the same destination, but just get there with different technology.

I am not saying if you took out your tube pre and started using the PWD volume control the same would happen in your system. It is all system dependent.

But again, our music reproduction objectives are precisely the same.
It makes a lot of sense to bundle preamp and dac these days much like pre-amp and phono pre-amp have been bundled into some pre-amps for years. The fact is digital is the norm now, not phono. So it is a natural thing to do. May not be the best/right solution for all. THat is why there are still separates for purists who care, like me.

True digital integrated amps, like the NAD M2 (all integrated amp functions performed in digital mode except final conversion to analog to drive speakers, though that would likely be done Class D style as well) are the next logical step in the evolution of audio technology and will become more common over time. I would love to try one today and strongly believe this is where things will tend to go over time, and it will all be for the better soundwise as well....

Hey I know that is heresy to a lot of old time analog lovers like myself, but why resist progress? After all , we all love our HD TVS, right? No reason all digital audio cannot be as satisfying, even today. Its the wave of the future. BEst to ride it rather than resist it.
Edorr,
You have found a solution that works best for you and that`s a good thing.I`ll assume we are all basing our choices on 'actual' listening experinces.I don`t believe top quality preamps are "dead end technology" or will ever be,in fact they seem to be improving.

As long as there`re listeners who hear and appreciate the superior sound quality these preamps offer there will exist a market for them(this won`t include you obviously).
Grannyring summed up the sonic differences very well, I imagine we have similar hearing and listening priorities.Edorr, there`re certainly others who hear things as you also.

For those who say the improved body,tone and dynamics is a coloration, well all I know is this is much closer to what I always hear with live performances(for what ever the reason may be). Edorr you may find your approach is closer to what you hear live as well. At the end of the day we all choose what we feel sounds most right.The lean,clean,thinner sound(less tone and body) is far less realistic and convincing for me.I`ve made my choice.

Edorr, one look at our respective systems would make it clear we have certainly taken different paths to find our individual sonic bliss.
Best Regards,
Digital volume controls are much more troubling in my mind, as the only way to reduce volume is to start discarding data.
I think it comes down to the type of sound one likes. Both are ways to build a system and they yield different results - sound of music. As the post above states our actual experiences differ because we all like and are pleased by different sounding systems.
So I ditched a $10K 2 box preamp (Modwright 36.5 LS/PS) in favor of a digital volume control, simple because taking it out sounded better to me.

Here is another consideration. Price / performance. Let's say you have a 4K DAC with a build in volume control, and you have $10K in the kitty for an upgrade. You can either buy a $10K preamp and put it behind your DAC (throw in some money for cabling too), or you can buy a $14K new DAC with volume control. In my experience the SQ improvement per $ of the DAC upgrade will be substantially higher than getting the preamp.

Again, I am talking from experience not theory. I recently spend $10K on upgrading my DAC and have fiddled with various preamps in the $5 - $10K range, and there is no comparison. Unless you have analog sources, preamps are dead end technology, and will eventually be replaced by the VC build into DACs. These DACs will also serve as the digital switching hubs. Some are integrating music servers, some will have digital room correction, cross-overs etc.
Hk_fan, in the case of digital domain volume control this is certainly not the case - you do in fact eliminate the "preamp circuitry" entirely. I don't know precisely how Empirical Audio's and Weiss volume control work, but I suspect they also eliminate circuitry and implement VC through a fundamentally different architecture.
Charles1dad, you said it very well and my experience is the same. No active preamp in a system is wonderful sounding to some, but I have always found the resulting sound cleaner, lighter and lacking in body, weight, natural tone and impact. No active preamp systems seem to provide more detail and can certainly be quieter, but over time I became aware that the perceived transparency and detail was really a result of other important musical cues being missing.
SteveN,
I``m not an engineer or electronics component builder and thus lack the background to debate at all on technical grounds.
All I have to offer is based on hearing and I trust my ears and my spontaneous reaction to what I hear or emotional response (does it involve me or not and to what degree)What ever steps it takes to get there I`ll do it.

So far in my listening experiences premium quality tube preamps are an asset and clearly improve the sound quality. I`m sure the actual builders/designers of top level preamps could explain why their products improve performance and articulate the reasons(technically) quite well(which I`m unqualified to do ).

There`re just going to be proponents of both sides,direct connection vs active preamps,it`s great to have choices in the marketplace.
Regards,
All good tube active preamps probably do improve the behavior of the amps, particularly dynamics, because they have sufficient drive compared to resistive passive linestages or op-amp DAC outputs.

However, and this is a big however, removing them from the signal chain is even better.

What you must understand is that some DAC volume control technologies do not "replace" the active preamp, they actually eliminated it. There is actually no preamp circuitry in the signal path at all. It is exactly like connecting the line-out of a DAC directly to the amps.

When you do this, the distortion, noise and compression that is in every active preamp, even the most expensive, is eliminated. Sound quality is a LOT better IME, particularly when the drive of the DAC is sufficient, like the drive (current) of an active pre.

Steve N.
Empirical Audio
"Wonder why no one has build this"

Empirical Audio and Weiss both have it, at least variations.

Steve N.
Empirical Audio
"The reason remains somewhat unclear but to the ones I spoke with it was the challenge of the circuit. I somehow doubt that is why, I think it more an economical one and we need a frank discussion of that."

I can speak to why I did it in my DAC. It was strictly because there was an opportunity to leverage the D/A technology to create a superior volume control with lower noise, distortion and no compression. It's all about performance. My volume technology can only be done within a D/A converter and cannot be adapted for analog circuits. If it was inferior to other active analog volume technologies, I would not have done it.

I believe other manufacturers typically add inferior volume control circuits because their competition adds this feature, so they have to add this feature. Their marketing depts decide for them. This all got started by one DAC manufacturer IMO.

Steve N.
Empirical Audio