Most DACs do not use passive analog attenuators, the attenuation is done in the digital domain, by dropping bits. At medium to lower listening levels, they lose a lot of detail, and the sound quality suffers. A dedicated, active pre-amp has high quality output stages that are designed specifically for driving amplifiers. Sometimes, well designed passive pre-amps can drive some amps very well, but it can be hit-and-miss. You may want to look at a DAC like the Bricasti M3, which does have a good analog, variable pre-amp output.
DAC DIRECT IN TO AMPLIFIER OR TO PREAMPLIFIER
For the longest time, I believed that the best preamplifier is no preamplifier. Eliminating a component from the audio chain would yield less distortion & greater purity.
Recently, I have had reason to re-think my logic on the matter - and I am (I think) changing my mind. Better said, assuming that the preamplifier in the component you are using (in my case, a DAC) can produce 95% or greater quality sound compared to the preamplifier component, then no preamplifier is the best option. The 5% represents the (estimated) loss of fidelity in adding another set of interconnects.
That said, most DACs do not have an outstanding preamplifier built in. I think most have average passive attenuators, and the better DACs have active preamplifiers that are very good - but not as good as a quality preamplifier.
What are your thoughts?
94 responses Add your response
My Sansui alpha integrate , a vintage product from 35 years ago i used for my headphone, i decided to upgrade from it with one of the best reputed and reviewed tube amplifier for headphone or efficient speakers and pre-amplifier in the world for his price...One month ago... I return it on the spot after one hour listening ( he was in used state from the manufacturer ) ... No comparison at all between the two amp. for serving my hard to drive and picky AKG K340 gem, i lost a lot of money for me in the process, postal fees, insurance and customs...300 bucks... 😊 But i learned that all is about synergy and a vintage marvel could be not an obsolete piece of trash but a top product even today... Then it is useless to proclaim rule as tube amp are better or pre-amp are necessary etc... Too many exceptions... it is better to proclaim as absolute a rule as : synergy rule ... Then if the integrate is top notch no need to buy a pre-amp... If the integrate is less top notch now you must match the pre-amp and the amp, and who knows replace your integrated simply by a better one...
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Paul, There is a large contingenet of people out there who think adding a preamp adds to the quality of the signal headed to the speakers. these are mostly the people selling preamps. Add to that those who have bought a pre-amp and want to defend their position. Certainly adding a pre-amp will likely change the sound. Different doesn't mean better. I"m a purist, similar to what you've described. the best the music can get is what is recorded on the source medium. as you process and amplify it, you can't add anything, only subtract from the perfection that exists at the beginning. The less you touch the signal, the better off you are. So I think you are exactly right to use your DAC to feed your amp. I do that with my Chord DAVE. Thanks for this thread, it did create the funniest statement I've seen on audiogon for a while. "DACs reduce vollume by dropping bits." Great plan: this guy is listening at low levels so he doesn't need all the music. we will just throw some of it away. Great example of how people don't understand digital. Jerry |
I agree with Jerry and Ozzy62. Though I do have an SPL Phonitor 2 I use as a headphone/pr amp in one of my system configurations and a Schiit Freya + I use as a passive-pre. I like swapping things around and in addition I have a very nice Tube Integrated in another system. I like mixing things around. The SPL is very nuteral and is a spectacular headphone amp. |
Until I heard my system with the Lumin X1 going straight into my amps, I would have thought a preamp to be essential. The Lumin made the sound quality so pure and effortlessly that I will never go back to a preamp. Unless you need a preamp because of the need for more inputs or switching capability, to me, the preamp just adds more circuitry, cables, footers etc. I prefer to keep it simple. ozzy |
Only DAC direct to amp that was worth considering for me was the Lumin X1. It was almost as good as the volume control on the Benchmark LA4. It has some gremlins at low volume, but still sounds good, and great in comparison to other DACs. The LA4 is perfect as a volume control. My current 2 DACs do not do volume, a Schitt Yggi+ Less is More and the Benchmark DAC3B. I am going to get 1 more DAC and I do not think that has a volume, hopefully not.
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I agree that blanket statements in high end audio can be problematic. But in this case, moderated by “in the majority of systems a high quality preamp” will improve the sound quality is fairly safe. Direct to amp typically produces a highly detailed but (typically described as) dead / lifeless sound. If you review the topic here on earlier posts you’ll see that 90+% have experienced this. Most folks that try it, go back to a preamp. I would recommend a high quality tube preamp. Some folks have done very careful component matching and been happy with the results. One has to wonder in those cases, did they value detail over musicality and natural sound, or was it a great match.
It will probably not always be like this, as the the shift to the digital world continues, DAC companies will apply more effort to analog outputs and they will likely get better. |
I've always firmly believed a great preamp is key to a great sounding system...it is the heart and soul. I had a fantastic preamp, the Zesto Leto and that cemented my position on how important a great preamp is. It elevated my system to a different level. I have tried several DACs straight to the Amp and never liked it. . YMMV |
Every situation is a bit unique, but preamp outputs tend to be better suited for driving the impedance of any given amp than a DAC output. That's not saying that aren't acceptable matches between some DACs and some amps, but it's primarily would preamps are made to do. Then there's convenience of input selection, phono stage, balance, tone controls, etc. |
I agree that it depends on the implementation. I’ve only come across a few DACs whose volume controls were worthy of being plugged direct into an amp. Some of my favorites here are the T+A SDV 3100 HV (which in all fairness has a true preamp stage built in), the T+A DAC 200 (its bypassable preamp stage is equivalent to a $3-5K standalone preamp), and the Aurender A20/A30. In full transparency, I am a dealer for both T+A and Aurender. That said, I have had many DACs on my floor and owned many personally before I became a dealer. Besides the older Modwright Transporter or Modwright-modded Cambridge CXN V2, I’ve never found any other DAC with a volume control less than $15K that sounded optimal without a separate preamp. This included a few Lampizator units, the PS Audio DirectStream, and the Mola Mola Tambaqui. All of those sounded worse, with the Tambaqui sounding significantly worse without a standalone preamp in the chain. |
I have a PS Audio Direct Stream that i ran directly into a PS BHK 250 amp. It was very pristine & revealing but seemed to be lacking somehow. A friend brought over his PS BHK Preamp one night & the difference was dramatic. Everything was more robust, rich & engaging. It makes no sense that inserting extra cicuitry can improve the sound, but in this case it did. It was so much better that bought a BHK preamp. |
I had tried both ways. While my preamp (VTL TL 2.5) was in service, I was forced to feed the Cary Audio 303/200 CD player directly to my ML 23.5 using the built-in digital volume control. Music sound up-front and I enjoyed it for a little while. However, I cannot say I could enjoy the music for a longer period of time. Once I got back my preamp, it was a completely a different story. Music was laid back, but depth and left-to-right imaging got more defined as opposed to direct connection. VTL 2.5 is a tube preamp (2x12AU7 and 2x12AT7) and male/female voices were so much better. I have two DACs in the system (AR DAC2 and DAC3) feeding Cary Audio SLP 03, another tube preamp, and I don't think I will ever go back to direct connections. Preamp is a must have in your system.
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There are exceptions ,such as like theT+a 200 dac great in every respect has a separateAnalog resistive ladder preamp section, Bricasti too has a dedicated preamp section in theirs , thatbeung said a real good $5k and up dedicated preamp such as the Excellent Linear Tube Audio preamp where you have better isolation and bigger power supplies better dynamics and imaging. , that being said Accuphase has a superb patented preamp section in their upper integrated amplifiers as does Luxman and top tier Gryphon. |
DCS Rossini Apex with and without ARC REF 6SE.
Night and day. I was kinda shocked how much the sound was improved by the addition of the pre-amp. Since I have only one source, I was contemplating selling the RFE 6 as I’ve moved to the UK….but a big fat keeping that piece forever is now my position. All my gear is in a London shop having the voltage converted.
enjoy…! |
This is a very timely discussion for me. I have been contemplating some changes in my system that would involve phasing out my current preamp. I currently have an old Audio Research LS-15 line stage into a Bryston 4bSST2. I have a Lumin T-2 streamer/dac connected to the LS-15. For some time I have been considering upgrading the LS-15 but have always considered keeping a preamp in my system. Recently I have become interested the the Lumin P-1 streamer/dac/preamp. I realize it is not a true preamp. It appears to be a streamer/dac with more inputs offering more flexibility. My music listening is almost entirely streaming but I do still have a CD player and turntable that I occasionally use but to be honest they are largely ornamental components in my equipment cabinet. The P-1 would provide the connectivity to keep these components in my system and offer the ability to play them. I do realize that the P-1 does operate totally in the digital domain and as such does not have the analog circuitry of a conventional preamp so it only provide the preamp connectivity flexibility but not the potential analog advantages of a preamp. Does anyone have personal experience with the P1? Would it be best to upgrade my preamp to another conventional pre or replace it with the P1? I realize if I ultimately want to answer this question I will need to make the comparison in my own system but am interested in from Lumin P1 owners or those who have heard this streamer/dac/preamp. The P1 would be an upgrade over my Lumin T-2 so I am confident in that move but am less confident about it replacing my preamp. |
In the camp of preamp here. An absolute necessity to feed my amp both multiple analog and digital sources. As for sound, the wyred4sound STP-SE stage 2 is wonderful, passive until 64 db, active above. With my dac set at max volume to bypass its preamp feature, the STP only needs 20 to 30 db setting, utterly quiet in passive mode. |
@blackbag20 My summary of this thread would be that there are 2 camps, one likes adding a preamp, and one doesn't. Nobody knows which one is right, and probably it depends on the system, there is probably no single right answer. but what I think you found valuable is the explanations of why people had their opinions helps you to form your opinion. It is great to hear that a thread like this, that draws no clear conclusion, still is useful to the reader. Jerry |
I moved from and integrated to separates a while ago. Had already gotten a nice amp and was already enjoying it using the integrated as a pre before selling iit. In the interim between, I used my dac as the preamp to still very good effect. There were some qualities that were present that wasn’t delivered via the pre stage of the integrated, however at the sacrifice of overall sound stage. Nonetheless, I was still enjoying it, not exactly a dealbreaker by any means. But then, my preamp arrived…and man? If it didn’t completely transform my system. I thought at that moment “so this is what hi-end in my own room can sound like”. Strangely, things became more true to signal. Not less. More balanced, yet more real. It wasn’t stage this, clarity that…it was everything combined, a major change toward hearing what the artist/engineers were intending. Really, the first time I was experiencing goosebumps on the regular. To me it really seems it boils down to that output stage, output gain and synergy with your amp/speakers. I’m still wondering, however, what a serious dac with a profoundly well built analog output stage might still do on its own? Still wonder about that more direct path when applied well. But it would need to be configured with the right gain (or gain flexibility) along with the latest discrete design topology. Tech is improving rapidly, and it’s very regularly applied to audio gear. Not doubting that it isn’t already achievable, just not (yet) as available in the more affordable range. |
Hi, Personally I've had over 150 different DAC's and right around the same number of preamps. We import audio products, mostly from Europe and the UK and I get to A/B many different brands. So here's my opinion and again it is just an opinion. It really comes down to the level of your system and how resolving that system sounds. If you go DAC direct and the DAC is properly designed then it can sound extremely musical but will lean more toward the digital side, sound wise. When I add a world-class preamp to my system then that takes the system towards the analog side, sound wise. They're very different sounding but I would say if you're looking for a highly resolving system then a high quality preamp is an absolute must. The one component I couldn't live without is my preamp. It really comes down to the preamp and capability that the preamp has to improve your system. There is an old saying that I firmly believe in audio "you don't know what you don't know" and until you have tested this theory with several different preamp then it's impossible to know the correct answer. Robert Neill
President Worldwide Wholesales |
Clever post thanks worldwidewholesales... There is different audio system and synergy and price level, a rule as : always add a pre-amp or : never add a new component in the chain, such rules make no sense... I dont need a pre-amp myself, some others can benefit from one... There is NO RULE HERE , there exist different gear synergy, different acoustic conditions and environment... Rule number one : dont invent a useless rule make a useful experiment and learn from it...😁 |
In case you need other views, this is a topic which comes up in this forum.
https://forum.audiogon.com/search/index?utf8=%E2%9C%93&query=DAC+into+amplifier |
Good call @worldwidewholesales. It might be worth digging into why this is with a little more explanation, and others like @bigkidz may be able to better articulate. Inside a DAC, there is of course an analog conversion and output stage. In most cases, the job of that is to output a signal at line level with a specific voltage and impedance. Many amplifiers benefit from not just a higher gain coming from the source or preamp, but both a quality signal preamplified with quality voltage and current and matching impedance. When this is done well in a DAC and an amplifier is matched with it, there is a chance for magic to happen, but the chances of that are very slim. While many people who are in the “DAC to Amp” camp believe in the “less is more” philosophy, that a preamp is a straight wire that doesn’t inhibit anything, or doesn’t believe in a preamp at all, they are potentially depriving themselves of the benefits of a properly preamplified signal as well as a quality attenuator that does not add noise to the chain. In my opinion, I would always opt for the properly preamplified signal and accommodate a light level of noise (mostly inaudible) vs risking the mismatch or subpar signal delivery to attain a lower noise floor.
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Only correct answer: "It depends" Many fallacies on resolution between digital and analog volume, pot, vs. stepped resister vs. optical vs. transformer. Too much "religion" on all sides. Listen for yourself. My personal belief is implementation matters more. From an engineering standpoint, the answer is driven primarily by the resolution of the source. Well, can't resist. Logic may say dropping bits is less resolution, but did those bits contain data? Redbook, 16 bits, but a remastered tape with less than 80 dB DR, you drop one bit. Did you lose anything? Fancy 24 bit stream. Is it really 24 bits of resolution anyway? Analog volume. Did you lose anything or is it below the noise floor? Digital can be more accurate but does that matter? Pots add noise, but is it audible? Do you hold to a believe from poor or obsolete equipment where it did make a difference? Any method, reducing the level is reducing the audible dynamic range. It depends. Some DAC combo line drivers are not the best. But, are they any different from a DAC only line driver? Some are, some are not. A lot of combo units it is the same, just one mode fixes the volume by whatever internal method it uses. It depends. Do you want to add any distortion? Tone controls, balance, maybe sub sonic or sub filtering? Differing harmonic distortion from tubes or other methods? There is a reason tube buffers have a following, just as some want the most perfect squeaky clean. Your choice, so it depends. Do you need additional input selection? Conversion between balanced and single ended? Remote controls? Maybe a built in headphone amp? It depends. Budget ( like my DX3pro+ all in one spec chasing wonder) to excellent ( Ares maybe, HOLO?) to stratospheric, ( take your pick) you get fewer features which pushes you to DAC, preamp, headphones amp and you expect them to pay the careful implementation of their chosen technology. After all, they want to sell you another billet case and external power supply so why add $20 worth of parts when they can sell you an $5000 box? 😁 But then you are adding in all those magic cables that destroy the world. Can't win for losing. Some advocate passive volume controls of various technologies. Less is more. SINAD perfect. But, it depends. Does the source have the current to drive a low impedance load? How does the following unit handle a variable impedance feed? Super long cables that need low Z output and high current to drive the cable reactance? I tried one, and with my stuff at the time, I was not impressed. So it depends. What are your needs? Can you hear a difference, or are you looking for some undefined magic that can't be measured based on a You-Tube made up way to sell adds or products? Your choice. You can always try a Freya+ and get tube, passive and ss buffer all in one. Decent I believe, but not prestige level. On my desktop, I need more than unity gain because I reduce the player output by 3dB ( yes digitally) to prevent filter clipping in my DAC. HUGE difference for the good. With my giant 2W amp and a all-in-one DAC/pre with only gain of 1, I did not have sufficient listening level for some sources so I have an active preamp with a gain of 4. My main stereo with a higher gain amp, I never get close to a 0dB output, only negative so I don't need another gain stage. I see some "prestige" preamps that are actually analog in, A2D, digital volume, then another DAC. Go figure. It depends. IF I change DACs and IF it does not have remote volume, then I would be looking at Denafrips, Musician, and Schiit preamps. Decent, not esoteric. I can only afford to pay for sonic improvements. Not magic. |
I recently made a change in my system. I purchased a Schiit Kara preamp. It’s specs are excellent and it’s as transparent as anything I’ve heard. You can switch between passive and active. In passive mode only the relay controlled resister ladder volume control is the only thing in the path. With balanced connections my DAC has enough output for the amp. I’ve listened in both passive and active and there’s no obvious difference other than volume control setting. But it’s new and I’m still listening. |
I know a lot of folks do not care for this guy or his musings, but he has a point if you are digital only. https://youtu.be/81RQLo0tLHE?si=t9BKS9t34O0bESV2 |
@blisshifi “…T+A SDV 3100 HV (which in all fairness has a true preamp stage built in)…”
That is really interesting. Perhaps what that means over time as digital becomes more dominant… DACs will include preamp stages… and really ultra high will continue to require separate preamp functions. |
@ghdprentice Perhaps… but I am in the camp of associating T+A with ultra high end. The SDV 3100 HV is a $38,750 component. While T+A does offer the standalone reference DAC at $36,500, they integrate the power supplies, analog output and volume control from their $22K reference preamp for an additional $2,250 into the SDV. The SDV unit does have a lesser feature set than the dedicated preamp - less inputs and outputs; no option for built in phono, no room correction or EQ - all so it can fit in one chassis, but also to reduce any culprits that may result from combining analog and digital circuits closely together. I am a big believer of isolation and agree that typically it is best to have separate circuits in separate chassis’, but in a few manifestations such as the SDV 3100 HV, I think world class results are possible in integrated offerings. |
@carlsbad2 “…My summary of this thread would be that there are 2 camps, one likes adding a preamp, and one doesn’t..” I get a different take all together. It seems there is consensus that most of the time a real preamp is required, it can be built in, or separate, or the music looses some really important characteristics. While there are exceptions… generally very high end, they are that… exceptions.
This brings up the problem to those assembling systems… especially if they are not auditioning extensively along the way. You put together a system without one and you don’t know what you are missing. And this missing stuff is often the most important stuff… what allows you to enjoy the music vs the system. So, without a preamp you often get amazing detail but somewhat flat lifeless presentation. This is a recipe for listening to the guy in the third row of the symphony move his foot as opposed to getting lost in the music you are listening to.
Us old times tried this by removing their preamp, so had the advantage of noticing the difference… then for whatever reason put it back in. Folks these days my never put one in. |
Some really great points have been brought up in this string. Different systems will adapt better to change and others will not. Really measurements will play a small part in this process and yes cables or lack there of, can make a difference regardless of what your crusade/religon.I have listened to systems that on paper measured well, but in application sounded like buffalo chips. Expand your Third Eye and give some things a try, you maybe suprised. I love this and I am quoting @ghdprentice
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Very true, both wrt to preamps and with other stuff too. In my case it was dual subs, which I should have added years ago.
Not everyone has the same experience with loss of depth and dynamics, but it was mine with the 4 or 5 resistive passives I have tried in my system. The internal volume control of the Metrum Adagio DAC was better sounding and certainly not flat or lifeless, but it leaned more toward a clean/detailed sound without providing the degree of body and rich tone I enjoy. In addition to the Adagio, the only other passive solutions I have tried where that "somewhat flat lifeless presentation" didn't occur used Slagle autoformer volume controls (AVC) but those two units had their own sound that, while nice, I ultimately moved on from. Regarding DAC volume controls and loss of bits, here is some reading material explaining how bits can be lost in some situations. The article also includes a couple of illustrations by ESS showing how analog volume controls lower both the signal and the noise while digital volume controls can lower the signal while leaving the noise unaffected, which has the effect of reducing the S/N ratio. Not all DAC volume controls are the same. The approach practiced by Cees Ruitenberg at Metrum and at Sonnet (now together under one roof!) involves changing the volume by varying the reference voltage of the converters, which, in conjunction with an algorithm they employ, preserves S/N. In the end, as mentioned by others here, you really need to try things out for yourself and preferably in your own system with the music you listen to. |
I also use a Lumin X1 directly into the Lumin AMP. SQ improved after removing an excellent Rogers High Fidelity KWM-88 integrated amplifier modified to use KT 170 tubes. I tried many different connects from AMP to streamer and found that made an audible difference too. Not really news. The Lumin(s) use Leedh Processing Volume Control. No lost bits. Does this mean than some/all Lumin’s do not need a preamp? I’m not touching that one. Far more experienced than me forum members @blisshifi @worldwidewholesales who have benefited from having listened to far more equipment and know their stuff should be heeded. |
@ghdprentice Indeed, well said. It would be hard to put together a system just by reading on the internet and that is what some people do. Others try to do a lot of auditioning either in showrooms or using liberal return policies. I do it another way: I am good at buying and selling used equipment. The key is never to buy junk. So I buy a lot of equipment and resell the equipment that doesn't suit me. Jerry |
@carlsbad2 + 1
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Mahgister- "you don't know what you don't know". In this case, this doesn’t have anything to do with system synergy, IMO it has everything to do with the quality of the dac and the preamp. A lot of dacs are noisy when using as a preamp so a preamp is a requirement. Some dacs like mine have attenuation to compensate if there is any noise going directly to the amp. Before ps audio came out with their BHK preamp, Paul’s recommendation was to go directly to the amp from their dac. I had a new $5000 preamp a few years ago that I used with my dac, and other sources. I took the preamp out and went directly to the amp, played with attenuation, and the sound quality was the same, so I sold the preamp. The BHK preamp might be better than the preamp I had, but when looking into making the dac sound best, most of the conversations I saw was to get the dac to perform best in its sweet zone, and this involved using or not using the attenuation feature. For example, some people claimed the sound with attenuation on sounded more smooth, while others claimed it was lifeless. Same goes for attenuation off. Let your ears determine what sounds best after you run thru the many different configurations. |
We can have words and concepts learned by minimal acoustic experiments in our room.. Then we "dont know what we dont know" but we can guess it by listening our speakers/room ... There must be a balance between all acoustic factors for exemple for a brass orchestra timbre of trumpets ,french cor , tuba, trombone, to be experienced rightfully with clear distict timbre tone playing in a spatial clear distibutions and transients and dynamic and the "rise-duration-decay time " and all the spatial distribution and extent qualities in 3-D...And we must learn how to control these acoustics factors in our room... Then " i dont know what i dont know " it is true but i did not have so much ignorance as 12 years ago when i did not understood and perceived yet the contribution of each acoustic concepts ... But i learned them by experiments and how to control in some degree and act on them for better and worse... then you are right :
But i know even if i never listen to it yet what could be my best upgrade and why and how...there is a minimal acoustic satisfaction threshold and i reach it at low cost and i am more than happy... It takes lot of hard work and years of experimenting to reach it... Most people dont do that...They then catch upgraditis...And they, in an opposite way to me, suggest branded name of gear they own for upgrade not acoustic and electrical and mechanical embeddings as more fundamentals with the necessary gear synergy as i do ... For sure we must learn and buy and make mistakes... I did for years ... But my point is that we will makes more mistakes and create more unsatisfaction if we dont learn basic embeddings controls... Acoustics being the most important... Dac upgrade is half the time unnecassary.. People do it because they dont know how to reach synergy and they dont learn any acoustics concepts by EXPERIMENTING... I say that because i did exactly this BEFORE experimenting and learning... My post made sense ONLY for people with a limited budget and people who cannot afford to buy illimited dac pieces or gear pieces to try them... Experimenting may cost nothing, but it cost much in time and in reading, this is why few did it...This does not change the fact i spoke about : audio is about synergy and especially embeddings controls not about costlier piece of gear... 😊
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