Info

a short diary of some part of my life.

This all started when I found Audio-gd, a small audio manufacturer led by He Qinghua or well known as Kingwa. He makes superb audio gear based on designs that can only be found in some of the most exotic audio gear on the planet. Oh, don’t worry about the price, they are very reasonable and to be honest, they are quite reasonable for what you get in the unit. The designer/owner himself is a very honest person which is a huge plus in my book; there are very few honest personalities in this audio world. I’d have a hard time finding similar products that can compete well in Audio-gd price brackets. I have had a few Audio-gd products, my newest toy from them is the new Audio-gd Reference 5 DSP.

Reference 5 idea was suggested by an audio forum member who owns a complete Audio-gd system. He suggested Kingwa that Audio-gd needed a DAC to be paired with their smallest balanced headphone amp/preamp, the ROC. The chassis was readily available, so Kingwa only needed to cramp several PCM1704U-Ks into the chassis. I never thought it could be done at the time as the chassis is quite small for a fully balanced PCM1704U-K-based DAC. Not only did he manage to design one but I think he brought up a few interesting ideas about the design which will be covered below.

Design

PCM1704 ✭
The RE5 uses four Burr-Brown PCM1704U-K ~ R-2R/multi-bit chip, two chips per channel. It’s a fully differential/balanced DAC. The PCM1704U-K is considered to be the best sounding DAC chip. It is also the last of its kind.

DSP-1 ✭
There are two kinds of Reference 5 ~ RE5. The DSP version uses Audio-gd DSP-1 and the DF version uses the DF1704 digital filter. DSP-1 is a powerful proprietary programmable digital filter processor developed by Audio-gd. Burr Brown DF1704 is a typical digital filter used in many PCM1704-based DACs. For HDCD lovers, unfortunately, none of RE5 digital filter options can decode HDCD, you would have to choose one of their DACs that is designed specifically for PMD100. DSP-1 uses Altera Cyclone on its’ heart, it has comparable processing speed to an Intel Pentium II processor. If you want to play with DSP-1 settings (switchable via DIP switches on the DSP-1 board), here is the diagram: http://currawong.net/head-fi/DSP_settings.html

DAC Reference 5 has built in DSP-1 processor, which is a Two-channel Digital Interpolation Filter and data in-phase processor for digital audio. This Device offers advanced features for high-performance digital signal processing (DSP) applications up to 250-MHz. Data and Master-clock in-phase processing are without jitters. So DAC Reference 5 can offer a clear and focused soundstage, apart from accurate and neutral reproduction of the recorded disc/music.

Theoretically when using the DSP1, data will be running parallel, achieving near zero jitter state, no matter the level of CD transport attached, be it hypermarket grade or hi-end level, you will still be getting the best and similar sound quality! Practically, through some experiment, although we could perceive the sound quality difference between differently priced and level of CD transports (as an audiophile, you just can’t just follow pure theory, but you must also venture the practical side too), but final result shows that using entry level CD transport or hypermarket grade DVD player, the improvement of sound quality is huge compared to typical digital processor chip like PMD-100, DF1704 etc.

ACSS & Overbuilt Power Supply and Filtration
All the processing/filtering after the DAC is done in the current mode ~ ACSS (Audio-gd Current Signal Sytem) which is a lot less harmful to the sound than voltage mode. Each PCM1704U-K has its’ own ACSS module. It has zero feedback analog stage, discrete output stage ~ there is no op-amp/IC, no coupling capacitor on the signal path, and all DC coupled. The power supply is monstrous, it has nine groups of parallel voltage regulators to purify dirty power and provide clean power to the digital board and analog stages. There are two beefy R-Core power transformers, each of them serves different purpose, one for the digital board and the other one for the analog stage. R-Core transformers are arguably better than torodial transformers. The transformers, ACSS modules, and IEC socket are carefully shielded with copper sheets to avoid interference. Each and every section of the DAC is heavily regulated. Those are not marketing hypes, they are just good designs.

The ACSS is a non-feedback technology made with discrete amplifiers. Most people know the global feedback design can offer better specs in test measurements, and non-feedback can’t do well in test measurements but can offer better sound for the human’s ears. Here is a conflict of the classic circuits. But the ACSS opens a new field, it can offer a least coloration sound which is more neutral with very low distortion and high linearity. So it can retain the dynamics, detail and neutral sound but not sound bright or harsh.

Audio signals are usually transmitted as voltage fluctuations, such as what eventually powers headphones and speakers. Instead of this, Audio-gd gear sends the signals, including digital (a first as far as I know) as a current signal (electricity has voltage and current). The advantage is that the effects of components on the signal, including cables, are reduced considerably this way, and you end up with a cleaner signal. Also, in Audio-gd gear, after the signal is amplified, it’s changed back to a voltage signal. However, if you connect two Audio-gd components together using ACSS, the circuits changing voltage to current and back are bypassed, so both act as if they are one unit, improving things further.

Modular Circuits
Since the entire analog and digital circuitries are modular, users may easily replace modules in the DAC if there is any future upgrades. The DSP-1 is socketed onto the digital board and the digital board is lifted above the main PC board by three aluminum standoffs. There are two ACSS modules ‘hidden’ underneath the digital board. Recently, Audio-gd ran out of PCM2706 USB receiver, Kingwa posted an offer on Audio-gd website to exchange the USB input for another Coax or Optical input. To have another Coax or optical input, the digital board needs to be changed.

Inputs & Outputs (stock config):

  • 3 digital inputs: Toslink-Optical, Coax-RCA, USB.
  • 2 sets of analog outputs: RCA and XLR.
  • 1 set of ACSS outputs if one wants to utilize Audio-gd’s ACSS technology. That is another compelling reason to get one of their preamps, power amps or integrated amps.

I don’t use the built-in USB input, so I won’t bother writing anything about it here. For those who cares about the built-in USB input, it uses Tenor TE7022 24bit/96kHz USB receiver. The same Tenor chip can be found in Stello U2, NuForce HDP, NuForce uDAC-2, and Teralink X2. Instead of having a USB input, my new RE5 has two Toslink inputs and two coaxial BNC inputs. I figured it would be better to have no USB input as the technology is still maturing. There are various USB-SPDIF converters out there, new ones come out every a couple of months.

Build Quality

There isn’t anything special about its’ exterior, it has an old school fairly rugged brushed aluminum alloy case with solid aluminum feet. Unfortunately, the fit and finish of the chassis is still well below my expectations. There are scratches, gaps and excess materials all over the chassis. I own a Wyred 4 Sound DAC, comparing them side by side is like comparing a Lexux Vs. a cheap Chevy. W4S DAC’s fit and finish and overall build quality are top-notch, much better than the RE5; FYI, they are in the same price bracket. My main beef is sub-par parts selection that do not contribute directly to the sound quality, such as: cheap CMC RCA jacks (that can easily worn out after several usages) and flimsy ACSS connectors (I may replace the ACSS connectors with mini XLR). In all honesty, they make little or no effect to the sound quality and without a few trade-offs, the price would have been much higher (due to intensive labor required to assemble a unit). I would rather have a well designed innards than a beautiful chassis that may cost up to half the price of the unit and skimp on the quality of the components inside. Besides, I sit at least six to ten feet away, it looks simple and fairly beautiful. Overall, the build quality of the innards is very good. It definately looks handmade though. I prefer the circuit to utilize SMD parts as it will likely offer precision fit and finish.

The first thing that I noticed when I opened the RE5 was, it is massively populated and well laid out. There is practically little to no space spared. It screams great care that Kingwa has given in designing this DAC. Aside from RE5’s engineering prowess, I find many high quality components used inside the RE5, such as: Dale resistors, Hitachi transistors, Toshiba transistors, WIMA film capacitors, Solen capacitors, Sanyo OS-CON caps, WBT silver solders, Canare BNC, and Neutrik XLR. The input naming on the RE5 is simple and user-friendly. There is a switch knob on the face plate for switching between Coax, Toslink, and USB. It really is a very simple case. The chassis looks similar to a TEAC unit ~ it also has rounded corners instead of boxy looking cases like older Audio-gd gear. This chassis is also used for Audio-gd balanced headphone amp/pre amp, the Phoenix and the ROC.

Setup

All electronics are plugged onto a PS Audio Quintet power center. Quintet is the first passive power conditioner that I found to work as advertised, it cleans power and it protects any electronics plugged onto it. I’m feeding the RE5 with Squeezebox Touch and Halide Design Bridge plugged onto my Apple MacBook Air with Audirvana+). I use the RE5 XLR outputs to feed Wyred 4 Sound STI-500 (a state-of-the-art ‘wire with gain’ integrated amplifier). The speakers are Selah Audio RC3R on Sanus speaker stands. Several speakers isolation devices and room treatments are used to get the most out of the speakers. I have various analog interconnects, digital interconnects, speaker cables, and power cables but ultimately settled with Blue Jeans Cable. I have used the RE5 for several weeks to familiarize myself with the sound signature.

Now, about the Sound Quality…
It’s definitely an upgrade over my old DAC-19Mk3 ~ which beats PS Audio lower end model, Benchmark DAC, and RWA DAC in musicality. Everything seems to sound clearer and more dynamic. I can hear more passages in the music, the bass goes deeper and better tonal balance. It produces a very smooth sound signature. The sound placement is right where I want it to be which is on the center of a stage. To keep this simpler, all the good things and improvements over those DACs mentioned above are easily distinguishable. Two months ago, I went to a jazz concert in Seattle. FYI, the theatre is renowned for its excellent sound system, it’s not like your typical concert venues which mostly offer mediocre sound systems. I still remember the superb experience listening to her musics live, how good the vocal was, listening to the same music at the jazz concert with the RE5 is pretty close. I have no trouble identifying instruments that are being played, instruments sound very real, and silky smooth vocal seems to evolve around me. I’m a big fan of movie trailer musics, musics created by Two Steps From Hell, Alan Silvestri, Hans Zimmer, Harry Gregson-Williams, and Steve Jablonsky are often hard to find, a few of them are only available on iTunes. Listening to a few Steve Jablonsky’s music blow my mind, it’s so surreal! The best thing about the RE5 is that it does not get in the way of the music, it simply disappears. This is what Hi-Fi is all about.

The thing about high-end DACs is that they offer very little performance for the money. This isn’t the case with RE5 or any top of the line Audio-gd DACs. While some may not like the sound due to its colored sound signature (sometimes, it’s too smooth), I think it’s really the sound signature of this particular DAC chips. I could be wrong but hearing PCM1704 on several occasions, almost all of them sound very similar. People might say, well, the PWD is better. PWD is only better at several key areas. No DAC stands out from the rest. If you like neutral but musical sound, you might like the PWD. But for the ultimate clean musical sound, you’ll like W4S DAC-2. Now, let’s bring DAC-2 on the table. The RE5 sounds good but DAC-2 betters it in some areas, such as: soundstage, speed, details, precision, bass. Speed and cleanliness in complex passages are the major differences here. RE5 can be somewhat slow and not as clean as the DAC-2. That does not mean the RE5 is not a good DAC. It is, it’s just it has been trounced by a newer generation DAC.

To make this simpler, here are the pros and cons:

Pros:

1. Musical
2. Vocal
3. Smooth, easy on the ears.
4. Natural, organic-sound.
5. Expansive soundstage, some people might like this.
6. Bombastic bass, again, some people might like this.

Cons:

1. Soundstage is not as precise as some of the best DACs.
2. Blurry in complex passages, especially instruments separation.
3. Not the fastest sounding DAC.
4. Some like the smoothness, but some say it’s a dark-sounding DAC, it is.
5. Bass is a bit scattered, again, not as clean as some of the best DACs.

In all fairness, without all those newer best performing DACs, this could be the end game. This could be the only DAC that you really need. After all, the goal is to enjoy music, not analyzing them. Other words, buy what you enjoy the most, not the latest DAC that you can get. Usually, DACs based on older DAC chips tend to sound better because designers have mastered making DACs around them

~~~

The RE5 is a great sounding DAC quite possibly one of the most natural sounding DACs that I have tried. I find it a lot easier to find flaws from my previous DACs ~ the only way to compare which DAC is better than the other is compare them side by side and spend some time with them. With this DAC, I often feel very excited playing musics that I have forgotten in my hard drives ~ I find myself searching for good music again. I don’t have any genre preference, as long as the music is good and it is well recorded, I’m willing to listen to it. DACs from well-known brands are often claimed to be great bargains for the money. Some even compare them by their prices, I’ve never seen a direct correlation between cost and quality in electronics. In my opinion, most of them offer very little for the money, in fact, they are often very overpriced. I would say, the RE5 is the ‘real’ bargain for money, a genuine high performance DAC for the $$. This is definitely one of the DACs that I’m going to keep for a long time. It’s time to take a rest and enjoy the music. Happy Listening!

Comments

32 Comments

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  1. Bixby #
    June 24, 2010

    Great writeup, you have me intrigued and wanting to try the Audio GD. I have a Benchmark DAC-1. When you got the RE5 what major changes did you experience vs th Benchmark DAC-1? Also, did you try the Halide with the Benchmark? Lastly, is the DAC-1 in your June 21 update the W4S dac-1 or the Benchmark?

    Did you also try the Audio GD DAC19 DSP?

    thanks for the writeup

    • August 2, 2010

      Thanks!

      Sorry, I should have been clearer, the DAC-1 that is mentioned on this page is W4S DAC-1. I never compared RE5 Vs. Benchmark DAC-1.

      I never tried Audio-gd DAC-19 DSP. I did own Audio-gd DAC-19Mk3 (DF1704 & PMD100) 🙂

  2. Peete #
    July 23, 2010

    Interesting blog my fellow A-gd lover !!! If you think the RE5 is good you ought to try the RE7 or MAX modified RE1 (major evil grin).

    It’s funny how the A-gd DACs worm there way into your heart and stay there…every time I deviate from my ref system (All A-gd front end, CD7/RE1 MAX,Phoenix MAX) I find myself counting the days, hours or minutes until I get back to the real thing…..in that way Kingwa and A-gd have spoiled me rotten.

    Good way to go… however….I also agree with you that gear that is genre specific is flawed and a design error.

    best regards,

    Peete.

    • August 5, 2010

      Hi Peete, I would love to try a RE1/RE7! But I don’t see myself owning it anytime soon, it is too big for my needs.

      I have swapped all capacitors (ModWright T, Black Gate, Nichicon KZ, Nichicon FG, Panasonic TS-HA) in the RE5 😀 so I don’t think I will ever get rid of it. It’ll be a classic DAC. ;p

      I only have one request for Kingwa, designs a better digital board with digital pulse transformer and I2S input. Although I prefer the RE5 compared with W4S DAC-1, I like the fact that DAC-1 does not need a superb transport to get the best out of it. RE5 sound quality greatly depends on the quality of the transport. Sure, there is DSP-1, but the differences between various transports are still noticeable. Fortunately, I have Halide Design Bridge which allows me to listen to great sound without any hassle. I have auditioned a few high end CDP, while their sound quality are superb, I dislike the hassle to stand up from my comfy sofa to change CDs. I am getting lazy… This is bad…

  3. WEE #
    August 2, 2010

    Hi. I using STI-500 myself to power my Dynaudio Contour S 3.4. I wondering if in anyway u find the STI-500 mid-range dry with the Ref 5. Is the high harsh and bright for Pop music at times?

    I thinking about getting an audio-gd Ref 8 as I find my current system a bit bright and hope Ref 8 will tone it down and give it some warm.

    • August 2, 2010

      Hi there,

      The mid-range is not not dry at all and the high isn’t harsh for pop musics, do you have any recommendation of what pop music I should try?
      There is an Audio-gd dealer in New Zealand, perhaps the dealer can lend you a RE8 for home trial. 😉

  4. vrln #
    August 27, 2010

    Thanks for the best Reference-5 writeup I´ve found anywhere on the net. You´ve helped me immensely, as I´m now exactly in the same situation as you (Sabre32 vs. Reference5) were. Mostly thanks to your writeup, I decided to go for a Ref5-DSP, as the PCM1704UK chip might be discontinued at any moment.

    There will always be new Delta-Sigma DAC´s (and to be honest I think the Sabre32 is probably the first one “done right”), but this might be the last time to experience the famous multibit DAC sound 🙂 In any case, it´s a “keeper” DAC even if you get a Delta-Sigma at some point later.

    I´ll also be getting the Halide bridge, but I´m starting with the Audio-GD Digital Interface as I got it for very cheap with the DAC. If you´re interested I can post about it here later.

  5. September 12, 2010

    Hi vrln,

    you’re welcome! 🙂

    I am very interested, feel free to post your impressions about the new Digital Interface.

  6. Dave K #
    September 24, 2010

    Don’t fall for Kingwas sudden change of heart of abandoning the PCM1704, it is not discontinued. He was competing in a market with a low profit margin due to their cost. With the Sabre he can keep a good margin and sell his toip of the line for $500 cheaper. I believe he has made a huge mistake and will eventually regret this decision. The PCM1704 is completely superior in every way to the Sabre, the only thing that the Sabre has done right is marketing, it is still Sigma-Delta 1-bit digititis.

    I recommend you pick up a Ref8 while you still can, best DAC ever made, and no it isn’t colored, its actually more accurate than the “neutral” series.!

    • September 28, 2010

      @ Dave K,

      I agree. I find Sabre DAC to be quite sterile if compared with the venerable R-2R PCM1704U-K DAC. PCM1704U-K is a very natural sounding DAC.

      About the RE8, hmm… interesting. Do you own a RE8?

      Hopefully I will get a chance to try it out when I visit China next year.

  7. vrln #
    September 27, 2010

    Actually I switched to the REF7 just before my order would have shipped. It´s here now and I´m looking forward to ordering a Phoenix next. Extremely satisfied with it, I´m pretty much done when it comes to my audiophile journey. The final purchase will be a CD7FV and then I can concentrate on buying music instead, and the only Head-Fi reading I´ll be doing will be the headphones forum 🙂

    Never would have found Audio-GD without blogs like this/Head-Fi.org…

    As for the Digital Interface: it doesn´t require custom drivers, so it works great under Linux. It is superior (smoother, more musical) to my HiFace, not to mention much better looking and easier to use as it´s not directly plugged into the often fragile USB port.

    • September 28, 2010

      @ vrln,

      NICE!

      I’m very curious to try out CD7FV, but it would have to wait until I settle in my new place or when I visit Audio-gd 😀

  8. Peete #
    September 28, 2010

    Dom;’t underestimate the importance of a HQ transport (especially so with the A-gd stuff). There really is no substitute for a top shelf spinner…My CD7 for instance made a sizable difference feeding the RE1 DAC…..I was using a variety of transports (from cheap to fairly expensive) previously and none of them (from top loader to 2K USD CDP’s with transformer coupled digital out) to computer transport (Auzen Prelude SPDIF COAX) they paled in comparison to Kingwa’s creation (now the CD7FV).

    At first I was hesitant to spend the 1K USD for the CD7 but now that seems like peanuts compared to the synergy the pairing produces. The inconvenience of an outboard transport that can play one CD at a time is the only negative but it’s a nuisance I’m more than willing to put up with.

    Could you shoot me a link for those T caps please. I’d appreciate that. 🙂

    Enjoy the RE5 !!!

    All the best,

    Peete.

  9. Peete #
    September 28, 2010

    Nevermomd about the “T” caps…FYI the Russian NOS series Teflon caps are just as good as any of the latest Teflon types and they cost a fraction of the CVH or others now beiong sold.

    An example the T-3 .1uf 600V Teflon cap sells for roughly 5USD each…. while .22uf T-3 600V is 8USD each. The T-1 series are simply lower V rating (200V typically) and smaller physical sizes … I like to use the T-1 .015uf 200V and 820pf 200V for bypass in SS gear and the larger T-3 caps in tube applications …they are simply outstanding caps , factor in the bargain bin price and they are an unbeatable part selection.

    Vishay MKP 1837’s are also excellent for bypass work.

    All the best,

    Peete.

  10. September 28, 2010

    I really want to try out a CD7FV, but the thing is, I no longer own vast collection of CDs. 😦 Most of my musics are now stored in hard drives. I will be traveling to China next year, first quarter of 2011. The trip was delayed for a year, I was supposed to visit China this year. When I visit China, I will make sure that I have time to visit Audio-gd to try out some of their toys. I’m interested in picking up a C-500 and a CD7FV. 😀

    Sure, here is the link: http://www.modwright.com/capacitors/12

    The price has gone up recently. It was $39 for a 0.1uF cap. I think if you ask nicely, they might give you the old price. 😉

    The cap is quite large, a bit bulkier than V-cap TFTF. I guess if you own a RE1/7/8/9, you won’t have any problems with space.
    Good luck!

  11. vrln #
    September 30, 2010

    Just a quick heads up… Kingwa just posted on the Audio-GD website that all PCM1704UK models will be discontinued within a few months.

    Probably not a suprise though, people have been anticipating this for a long time already. Anyways, if anyone is still thinking about the PCM1704UK now´s your last chance 🙂

    PS: still loving my REF7!

  12. September 30, 2010

    I hope Kingwa would reconsider his decision to leave PCM1704U-K. It defines Audio-gd. There is no other manufacturer that I know of that produces affordable PCM1704 based DAC. I guess the chip is expensive and then, there is DSP-1. 😦

  13. Kenobi #
    October 19, 2010

    Hi Ravenda,

    Thanks very much for the impressive review on the Audio GD Ref 5. I am seriously looking at this unit along with the newer NFB 1 & 7. Still undecided as to which model to choose but will hopefully come to my senses soon.

    Please keep us updated with your Audio-GD adventure. It is exciting and I am just one of many interested.

    Pete: If you don’t mind, please share your source for the Russian T-caps. Much appreciated.

    Thanks again,

    Kenobi

  14. John #
    October 24, 2010

    I have the RE8 and CD7SE FV for a few months now. RE8 without doubt is a great DAC that performs well above its asking price. For those who are consider CD7SE my recommendation is if you are playing CD and you want to squeeze out the best performance out of Audio-GD DAC you will have to buy CD7SE FV. I have tried RE8 with Sony BDP-5000ES bluray player, raysonic CD128 and an old laserdisc player as well as CD7SE. None of the make shift transports could bring out the last ounce of detail on the disc as well as CD7SE FV.

    • November 13, 2010

      Now, I really want to audition CD7SE FV. I just need to get rid of this annoying Squeezebox Touch to fund CD7SE FV purchase. 😀

  15. November 12, 2010

    Got the REF5 yesterday. Best DAC ever! Completely blown away as it took my system a few levels above where it had been. Soundstage seems infinitely deep. Way more presence AND focus to the musicians/instruments. Precise placement. As transparent as I have ever heard. BETTER BASS!? Incredible highs. I thought I already had some incredible highs. This blew my mind. I am a convert and a very thankful one at that. I heard W4S, Neko, Peachtree, Cary, even Wavelength, Isabellina… I think the Ref5 smokes them all. More passion in the music. How else to describe it I dont know. All those other DACs were honestly very very good but the passion is in the Ref5 as well as mindblowing sonics.
    Uriah

    • November 13, 2010

      Thanks for the comments! It is my best DAC as well, the best that I have come across so far. What strikes me the most is its organic sound signature.

  16. Kenobi #
    November 12, 2010

    If the Ref 5 is inferred to be a better performer than the PS Audio PWD here, then the Ref 7 should handily beat it. However, a recent user on the USA loaner program (via head-fi) thought the opposite.

    I suspect the Ref 7 he was listening to may not have the requisite burn-in required to perform at its best and also the user’s system may have been synergized to work with the PWD. Or, could it be owner’s bias since he bought the $3K PWD?

    Anyone care to speculate? Also, comparing the two machine’s innards, there is no comparison favoring the AGD gear by a long shot.

    Kenobi

    • November 13, 2010

      There are various possibilities why the RE7 did not or could not perform at its best. The tester was using M-Audio which is hardly a good transport. The PWD on the other hand, was using PS Audio PerfectWave Bridge. PWD performs at its best with PSA Bridge. It’s not a fair match. Or it could be because the tester’s personal preference of PWD sound signature.

      I believe Peete has heard the PWD and he prefers his RE1.

      Kingwa should have included Audio-gd DI to go along with the RE7 in that loaner program.

  17. Joaco #
    November 13, 2010

    Excellent review, Ravenda! And excellent comments as well!

    I´m hoping to get comparisons of the REF5, NFB1 and the Eastern Electric DAC. Can anyone help?

  18. Joaco #
    November 13, 2010

    Kingwa says that the difference between the REF5 (PCM1704) abd the NFB1 (Sabre) is that the latter makes voices sound “younger”. In all other aspects, they are identical.

    Do you all beleive this is true? We can notice that the implementation of the new chip requires a lot less hardware and this equates in more profit (and lower price for consumers). So, do they really sound similar?

    • November 13, 2010

      I don’t know and I don’t want to speculate. I never heard any of the NFB series.

      That’s one huge advantage of S-D over R-2R or any dedicated chip. Features that can be implemented in S-D chip are virtually limitless. ESS 9018 has built-in digital filter, digital volume control, 8 channel ~ 4 DACs/channel. It doesn’t need an external/separate digital filter like the DSP-1 or DF1704. It saves tons of space.

  19. Julien #
    December 24, 2010

    HI,

    Very interesting review. I’ve had a ref 5 DSP for about 8 months and really love it… My best DAC so far.
    It looks like you wen’t crazy on the parts upgrade… I use to do the same, now I’ve quiet down a bit. I try to go for the most critical stuff, and if something sounds good, I just enjoy…

    I wanted to ask you if you have tried different diodes in the bridge rectifiers. Like soft recovery diodes (ie “Stealth” diodes from Fairchild). In my experience, those can have a profound influence in the sonic presentation. But I feel it might be of little value on the DAC 5 due to the well filtered and elaborate power supplies.

    Regards,
    Julien

  20. Dr. John Dozier #
    January 10, 2011

    Best review of this unit on the web. I am still tossed between the REF5 and REF7. I will also try the DI. I have inquired about using Nichicon OSCONS in my unit and Audio-gd has been most gracious about installing them. About the teflons, I have been using teflon caps for 15 years, thanks to Jerry Foreman of Precision Audio(no longer in business alas) The best I ever found were Relcap metal encapsulated. These are no longer available since Jerry was the source(he was a consultant to Relcap) I have looked at the size of the Solen used by AG and the Modwrights appear to be the only ones that will fit,lengthwise, although they are a quarter of an inch longer. I assume they fit with no problem. Are there any ceramic caps in the design? If so I would like to replace with NPO/COG. Please let know if this is the case as the 1704 data sheet specifies .2uf ceramic bypasses on the 100uf electrolytics. Thanks again for a wonderful review. You should be writing for one of the mainstream audio rags. With sincere appreciation, John Dozier

  21. Hroon #
    January 19, 2011

    Hi ravenda:

    You wrote that DSP-1 switches can be used to make changes about over-sampling, digital filter?

    Have you or anybody tried turning off the over-sampling and digital filter to effectively make it a NOS DAC?

    I am interested in Reference 7 DAC in NOS configuration. Can someone share their comments on the sound quality if they actually have done that?

    Regards

    • March 8, 2011

      Hi there,

      yes, I have tried those configs. In NOS mode, it sounds dull. I never turn it off again.

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