Small form factor, budget DACs?

I'm trying to restore the musicality to my system, piece by piece. A few years ago my Jolida JD-602A CD player finally died and I've never really found a good replacement. I think really I've been mourning the loss and lacked the funds to get something of equal quality (since it was sort of a giant killer).

So, what can I get for < $400? Used is fine, but it has to be a compact form factor - I don't have room for another full-sized component. I think the 1/2 size form factor that Channel Islands, Musical Fidelity and Creek use is about as big as I could go.

24/96 is a plus since I have a bit of DVD-A stuff but not a necessity. I don't really have an opinion for or against oversampling, or regarding filterless DACs.

Here are the DACs that have popped up in my search so far:

$175 - Lite Audio filterless DAC
$250-400 - Ack! Dac
$200? - Creek OBH-14 - I'd have gotten one by now but I have yet to see one pop up on the used market. Probably a good sign.
$300-400? - Musical Fidelity X-24K - older DAC (circa 2000), but it looks nice and let's me stay with the appealing X-component form factor (I have an X-ACT and X-LPS now). Maybe a little overpriced - I can't help but think that for that money I could get something better
$400-600 - Channel Islands DAC - undoubtedly the best DAC on the list, but also the most expensive, so it would take the longest for me to save up the coinage.

Anything I'm missing from the list?
I highly recommend the Bel Canto DAC 1.1, at around $550 used. I owned the earlier CI DAC (your price seems to indicate the new one), and while it was pretty good, I found the Bel Canto clearly superior in all respects.

Other small form-factor DACs I have also owned:

Theta Cobalt 307: nothing special, dated

Musical Fidelity X-ACT DAC: un-musical and dull, dated, I hardly think it would improve even the oldest player

Musical Fidelity X-DAC v3: dry (perhaps "brittle") but quite detailed (like the Classe DAC-1 I briefly owned), but posessed of an impossibly annoying input-scanning "feature" that could not be disabled

I haven't tried the others on your list, but of the whole lot, if I were to do it again, I'd stick to Bel Canto or CI, and if the Creek came up cheap, I'd consider giving it a try. I know very little about the Ack!, but it might be battery-only.
Thanks for the great response, I'll add the Bel Canto to my "watch" list. It seems to be just a little bit more that I was looking to spend

Agreed on the X-ACT - that's exactly why I want to upgrade. I find myself listening to CD the least, even though it's what I have the most of, media-wise.
Out of curiosity, what are your thoughts on the old Channel Island DAC? It seems to sell for under $300 these days, which is pretty hard to argue with. How did it compare to the other DACs on your list?
The Birdland Odeon-Ag. It's small (weighs about 3 lbs.). It has a volume control for direct connection to an amp. Absolutely stellar sound. A bit over your budget. There is one for sale right now at $795 which is a very good price if the re-clocker is installed.
About the older CI DAC, I was well impressed with it for such a simple unit. It had reasonably good bass - not boomy, but not really in charge. It had surprising detail and presence, but it was a little bodiless through the midsection, and in comparison to DACs in the next price step, in the end a degree less detailed and spacious. The Bel Canto was palpably more lush, smooth and deep, and at the same time more in control of the bass, and more crystalline on the highs without brightness. The CI was extremely pleasing and capable - only by comparison to a costlier DAC of similarly exceptional value did it please less. Compared to the older DACs in this list, the CI was just way better.

Build quality of the CI is an example to others at the price. The Bel Canto is in the next rung of overall quality with better chassis + connectors (the RCAs on the Bel Canto being considerably more robust with thicker plating etc.) I liked the CI enough that I'd buy one again at the $225-250 or so used, but at a couple hundred more, I think the Bel Canto stands as the greater value. If I had $225-250, I'd buy the CI. If I had $500-550, I'd buy the Bel Canto. Both are great - I really liked the CI, I loved the Bel Canto. I 'd enjoy owning either (I've owned 2 of each over the years, I currently have one Bel Canto 1.1)
I would add the Scott Nixon, Audio Note and Audio Sector DACS to the list. You owe it to yourself to experience NON OS done right. You may never look at oversampling DACs again. I haven't experienced anything up to several thousand I would trade my DAC for. I know I would have to spend quite a bit more to hear a clear I haven't bothered. In most cases, I would be just pissing in the wind.LOL

Good Luck
If you value music over hi-fi, you need to hear a nonos dac.

The non-filtering, non-oversampling DACs are definitely something I've been keeping a close eye on, and reading as much as I can about them. I hadn't heard of the Audio Sector or Audio Note units before - they are both very sharp-looking units.

I had been thinking about the Scott Nixon Chibi Dac with power supply in addition to the Lite Audio and Ack! Dac's mentioned in my first post. Unfortunately, I can't find a lot of info comparing them to the other DACs in my price range, or even to each other - they seem to kind of have a dedicated following outside the scope of "normal" high-end. There's lots of very positive reviews of the Audio Mirror, which is a souped up Dac-Ah - that's the main reason I was looking at that one.

It's something I'm very interested in however. I'm a recovering tube addict who would love to get some analog-ness back into his system, and that seems to be the good word on these.

The Dac-Ah seems like a no-brainer gamble at the price in fact. It's my top choice right now, though Mwilson's words on the older CI dac makes me think it might fit well in my system. And then maybe in a year or so I can save up for that Bel Canto or Birdland DAC.
My advice (worth what you are paying for it) it to treat Audiogon like your personal auditioning service. Buy, listen, and sell if you don't like it. You will lose a few buckes each time (maybe), but you will be better off in the long run. Listening to the rest of us lather on about gear we own doesn't really help you in the long run...we all come with our own preconceptions...for example, I owned a Musical Fidelity headphone amp...couldn't wait to get rid of it, so I never reccommend their products to anyone...others obviously will disagree.
It's more work and will take longer, but you will be better off in the end.

There's another thing. Above I said go listen to a nonos dac. I love my dac (it's obviously a nonos), but just because it works in my dac, doesn't mean it will work in a Ack! dac or a Nixon or an Audio Note or a whatever. Listen,listen,listen


A good point and well made. I'm definitely not afraid to buy / sell / start over until I find what I'm looking for.

That said, I really value the input and experience of the community and plan to use that as a starting point. That's why I'm starting my search by soliciting opinions about where to start. If it wasn't for the AG forums, in fact, I wouldn't know about any of these new breed of DACs.

But I trust my ears over everything else. If something doesn't work in my system, I'll be the first one to kick it to the curb :)
Hudsonhawk - consider the Audio Mirror non-os DAC as well ($500).
Are they still selling for ($500)? The website implies they were doubling the price last year, and it lists the MSRP of $999. Is this a phantom price, and they still will sell for $500? Cheers,

The website price has always been $999 for as long as I've known. Here on Audiogon the ads have been listing the D2 (latest version) for $549 OBO. The D1 was $499. If you decide to order one email Vlad and make him an offer based on the Audiogon advertised price, not what the website states.
FWIW, I've communicated with an owner of the Bel Canto 2.0. He also owns the 47 Labs 4715 Shigaraki.This NON OS DAC uses the same Dac chip found in the Audio Sector, Scott Nixon, Audio Mirror, Lite Audio and I would imagine a couple of other DACs. He prefers the NON OS over the BC 2.0 for its musical presentation. The BC 2.0 sounds sharper and more precise from his description but loses out in the naturalness of the music,when compared to the NON OS. I think Brooks had it right. The NON OS are built for music lovers more than the HiFi crowd.There's no real way to explain just have to hear it for yourself.

If I had to describe it in words. I would say the difference would be like comparing tubes to solid state.
Thanks everyone for your advice. I decided to take the plunge into a non-os filterless DAC (Pacific Valve Co sells an upgraded Dac-Ah for just $220).

I'll post some impressions once it arrives.
Good choice!

These DAC-AH's are about the best bang for the buck and are cheaply upgraded to sound even so much better.

Hudsonhawk, Killer DAC, the huge difference I found with anything on it was a good 10 or 12 Gauge teflon/silver tinned power cable, Completly makes the bass and mid solid and far deeper sounding, vs. a little 2 dimensional and overly analog flat with the standard power cord.
Thanks for the tip! Well timed in fact, as I was just mulling over power cord options for it. I just got a custom made power cord for my amp here on Audiogon (from member Synsurd - a definite bargain) and was thinking about new cords for my preamp and the Dac-ah. I may look into something a little more extravagent for the Dac-Ah.
well, I was also looking for an inexpensive but good sounding DAC & a fellow who is local was selling a Scott Nixon Saru DAC+. Well, it cost me less than the DAC-Ah & so I took it for an audition.
I have it for a day now so I've played just a few CDs thru it.
I *think* I understand what Gmood1 is talking about - since I have the Wadia 861 to compare against.
Bombaywalla ,
you should hear a DAC like this with a better power supply.
I think you would be very surprised with how it sounds. The 12 volt wall transformer is meager at best. A toroidal based power supply is where it's at.
Toroid is better than a wall wart no doubt about it there brother, but also optimized battery supply is the very best! (No AC mains noises or time of day fluxuations, no more diodes...switching noises, no more harmonics, noise floor it ultra black, so much more resolution and dynamics!).
Which is why my latest digital purchase is battery powered. Not only do I want to isolate it from the wall. I want to isolate it from my other gear.
There seems to be quite a few battery powered designs out there. I think it is something I need to investigate a little further myself to replace my Benchmark.
I agree battery power has its strengths. I also feel a well implemented power supply that runs off the mains can offer up serious competition. In some cases surpassing battery power in the dynamic areas. The condition of the mains from the start is also a factor I would think.

Too bad I don't have an extra Audio Sector Dac laying around. I would take you up on the challenge Flye and have one DAC battery modded. This way I could compare it to the stock unit. Don't let the size fool you. The digital / analog sections power inputs and grounds are separated on this unit. It is extremely quiet and dynamic all by itself.You're going to have to dig deep to out do this little guy in its present form.;-) I think Peter Daniels did an awesome job of engineering this DAC from scratch.

Please tell us more about your trial and include comparisons vs the Wadia...thx,
As a matter of fact on the power cord, We had 2 of the DAC-AH's stock and set up parallel into one preamp, one on the auxilary input, one on the CD input, A-B testing on the fly at the touch of a button all the same cables and transport, and trust me between 3 people doing the Testing (listening at the same time) we all determined the biggest direct tweak you can do was to use a good thick power cable, the Bass completly went to a much higher resolution level, far more detail, with the stock cord it sounded good, but was totally like a 1 note bass in comparison to the better cable...Soundstage might have expanded a little too which added to the deeper effect? We actually took it a step further and made sure to use both STOCK cables one on each dac and hear that they were the same in the first place and that the better power on either unit would improve it, and it did! we came to the conclusion there was a 20% solid enhancement with the power cord.

We then decided screw it lets pull out some left over deadner material for the panels and cover this sucker, and see what happens vs. the stock, well again a SMALLER but different sound difference, it just seemed a bit smoother sounding or more control with cleaner but nicer rolled off sound.. not sure what really accounted for this.
Undertow, I noticed the same thing when I changed from the basic 18 gauge PC over to a Belden 14 gauge PC on my DAC. I also heard an improvement when I plugged the unit directly in the wall verses into a power conditioner.

I'm not a huge believer in the PC thing..but I did hear a difference for the better going with the 14 gauge Belden verses stock PC. A friend and I also tested the Belden against a TICE power cord which was something like 8 Gauge. Again the Belden was the better of the two PCs to our ears.
The key is a good PC..not necessarily an expensive one though.
this particular DAC is the DAC+ version implying that it comes w/ a 4Amp AC power supply. The power supply is heavier + bigger than the DAC itself! It's got a fixed power cord. This DAC is NOT bass-shy - plenty of good quality bass & very good sound given its diminutive size.

Hey Spencer,
if I compare it'll be against the 861. I have NOT done that just yet - too many other domestic commitments + I'm being a bit lazy too (!). In & off itself, the DAC has a very good sound to it. Hard to describe what I'm hearing but if I had to use a few adjectives I'd say "natural"- the sound seems to be unhyped & "accurate"-badly recorded CDs still sound like sh** thru it.
I'll share more info as & when it becomes available. Thanks!
I have to ask? Where are you guys finding the DAC + or whatever for 220.00? I ordered these Dac's for me and 2 friends of mine just about 1 month ago, and emailed directly and actually asked them about what they think audiomirror and others have done different over the stock DAC? They emailed me back saying they are not sure what the upgrade details are on their units but that pacific are not selling any upgraded versions themselves and just deal with the stock version... Also I cannot find this version anywhere on the website, or is there another pacific valve distributor on another website? Thanks
Hmm, I found their upgraded Dac-Ah here, which I found through google - but now that I'm looking closer at their website, they don't link to this page from the index any more so I'm not sure what the story is. I asked them about the availability of the upgraded unit when I emailed them and they confirmed it - though maybe I got the last one.

They did volunteer that they had an upgraded Dac-60 (the tube dac) as well.

I'll let you know when I get mine. Obviously, whatever they say by email is probably the definitive answer.
Okay, the always quick-to-reply Pacific sent me a clarification on this. Basically the answer is "stay tuned" - they'll be updating their website in a few days to offer these upgraded Dac-Ah's.

I'll post my impressions of the upgraded Dac-Ah when I get it, so stay tuned for that too : )
Which is to say, it's a new product that just recently became available. When you emailed they didn't yet know they would be carrying them.

Sorry meant to put that in my post too, but it got lost in the shuffle.
Great Bombaywalla !.. sounds like you got a terrific deal on this DAC. I'm glad you have the upgraded power supply.
LOL... yes bad recordings still sound bad. ;-)

Good listening!
just to clarify - the non-oversampling DAC that I have is a Scott Nixon Saru DAC+. It has nothing to do w/ the DAC-AH that Hudsonhawk is speaking about.
I'd like to throw out the possibility of the older Museatex DACs, namely the Bidat and the Bitstream (if you can find them). I have really fallen in love with my Bitstream and it really has the charm of vinyl woven into its sound... I believe this unit helps digital "get it right".
I've just ordered a non-modded Dac Ah from Pacific Valve. For some reason I didn't see the modded version offered. Now I'm wondering about getting the modded version. It looks like the only difference is the op amps used. The unmodded just lists a generic Burr Brown, the modded lists Burr Brown OPA27M. What do people think of the difference? (I notice that the RAM mod includes the Select OPA627BP op amp.)

Correction. The mod with the Select OPA627BP op amp is the Poth not the RAM mod.
Looks like they just updated their website. They've also listed the modded Dac-Ah here on Audiogon.

I'll post impressions of the modded Dac-ah when I get it, but I won't have a basis for comparison to the unmodded one. If your order hasn't shipped yet, you might contact them and see about upgrading; I'm sure either way you'll end up with a great sounding DAC.
I currently run a PS Audio Superlink Gen. II 18 Bit DAC. I realize this is a dated piece(mid 90's?). Would the modded Lite-Ah DAC be a substantial improvement?
Spencer, Gmood1 & anyone who might be interested:
I finally got my lazy ass to make a comparison between my Wadia 861SE with GNSC Reference mods & my Scott Nixon Saru DAC+. A Goliath & David sort of comparison as the 2 units are from the opposite end of the spectrum. Not an entirely fair comparison, I agree, but these are the only 2 DACs I have on hand & so it had to suffice. So, that's the disclaimer, FYI.
Executive summary: the Wadia was overall better sounding (surprise?) but the Saru DAC+ was very, very, very good in & of itself. Too damn surprisingly good for its price point.

The setup is: Wadia 861SE with GNSC Reference mods fed into my CAT SL1 Mk3 preamp using Amperex white label 7308 USN-CEP & Ei 12AX7 in the line stage. Analog cable is TARA Labs Master Gen 2. Stock Sony DVP-S7000 transport & Scott Nixon Saru DAC+ with 4Amp power supply. Digital cable is XLO ER-6. Analog cable is Groneberg TS Premium.
I played a few CDs: Art Pepper "Winter Moon", Dee Dee Bridgewater "DEar Ella" & Reinhart Fendrich "All the Best". So, the comparison is not extensive.
Saru DAC+: a little brighter than the Wadia. Could not have noticed this if I didn't have the Wadia on hand. Excellent dynamics. Very natural sound. Plenty of bass but the Wadia has more. Really nice midrange.
Wadia: superbly natural. No hi-end glare & very smooth. Each instrument in the track is dilineated in its own space & its easy to follow all the instruments. The Saru DAC+ also reproduces all the instruments but they are not as easy to follow. The bass is tight & superbly controlled thereby making it easy to follow the bass tracks. This is not as easy in the Saru DAC+. The music just flows from the Wadia w/ great ease - no track seems to ruffle its feathers. In the Saru DAC+ I did get a feeling that it was "scurrying around" a bit. The DAC kept pace w/ the music & did a fantastic job but if it were a human being, it would have been a bit out of breath. Not so w/ the Wadia.
The PRaT factor of both DACs was really very good. In this short evaluation I could not find any serious faults in the Saru DAC+. The Wadia was much better. Was it as much better as the price difference? Certainly not! I also wonder if my DVP-S7000 had some power supply mods + some internal chassis damping would the results have been even closer? Probably!
So, this is a testimony to the progress that has been made in I.C.s that support the audio market. A few of them put together judiciously in a diminutive package can seriously challenge a Goliath like the Wadia 861.
I would compare the WADIA hooked up via Analog like it is and Simply connect the Digital out to the DAC, Then you have an Equivelant Transport with the Same CD loaded and can switch between your DAC and INTERNAL DAC of the Wadia on the Fly with the remote by just hitting AUX or CD on your preamp, this will be very fast to tell you which one is superior for cost. Take the Sony out of the equation entirely, you might find a suprise in that dac feed the same. Just a suggestion, then you have a straight up fair comparison.
Thanks for making the suggestion. I did think of what you wrote & decided not to go ahead because (1) the digital inputs have been disabled per Wadia's recommendation. They suggested that if the unit is being used as a single-box player, the performance is little better w/ the digital inputs disabled. I have to get this 60lb monster off the shelf, completely disassemble the top & bottom plates of the chassis to get to the DIP switches on the bottom to re-enable the digital inputs. A royal PITA! & (2) the Wadia running into the Saru DAC+ is likely to sound quite compromised since I will not be able to make use of the Clocklink feature (that now exists internally between the internal DAC & transport). From whatever I have read from other Wadia users, this Clocklink feature is of paramount importance in making the Wadia separates sounding superb. This is understandable - Wadia correctly implemented the clocking scheme by using the DAC clock to lock the transport. When one uses Wadia separates, all Wadia gear comes w/ the Clocklink feature & one is able to turn it on from a menu pick. The Saru DAC+ provides no such feature. Thus, the Wadia transport+Saru DAC+ combination is going to sound way inferior to the Wadia 1-box thereby leading to an incorrect conclusion.
(If there is any Wadia user reading this, let me know if I'm wrong. Thanks!)
Thanks for the little review...good stuff! Nice to hear the SN DAC did well against the heavy hitting Wadia. It's funny what sorts of things run through your mind when comparing units of such wide price differences. You kind of hope the expensive unit comes out on top. Especially if you paid for it with your cash.LOL $150 DAC against a $9000 unit ... yeap diminishing returns is a mother.

I wish I lived closer I would love to bring my DAC over for a comparison. If nothing else it would be fun.

Glad you can put your mind to ease a little.

All the best,
So, for those curious, I received my modded Dac-Ah and broke it in. All I have to say is, people aren't kidding when they talk this thing up. This is a genuinely musical, dynamic piece. It has a sweet, smooth midrange which does vocals exceptionally well; the imaging is "3-d" in a way I've only heard on higher-end pieces.

It's funny, I made a similar note when listening that Bombaywalla did while listening to his Nixon DAC - bad CD's sound *bad*. I've got two theories about this - I wonder if either these CD's have digital noise that's actually in the master, or these DACs are particularly jitter-prone.

Obviously I can't compare it to the unmodded version of the DAC, but I can definitely say that these things are the genuine article. It's the most impressed I've been with a piece of budget digital gear since the original Rega Planet.
I’ve got to chime in here. I’ve owned an Audio Mirror for a number of months and have experienced what everyone is talking about regarding NOS DAC’s. I couldn’t be happier with mine.

One of my biggest frustrations is this crazy hobby is a bad sounding CD. I’ve got tons of them that until recently, only listening to them in the office or car.

I just made a huge switch changing over from a Marantz SA14 SACD player which was mostly used as a redbook transport with the Audio Mirror to a digital music server which is PC based.

I ripped all my CD’s to AIFF files in iTunes and used a product by Roku to bridge the signal from my PC to the Audio Mirror DAC.

End result is improved sound on all CD’s but a major improvement on poor engineered CD’s. Yeap, I can listen to them all now. I think it’s all about error correction. A CD transport can only do so much. Near perfect CD error correction for today PC is a simple process for them.
>> 04-02-06: Hudsonhawk
>> It's funny, I made a similar note when listening that
>> Bombaywalla did while listening to his Nixon DAC - bad
>> CD's sound *bad*. I've got two theories about this - I
>> wonder if either these CD's have digital noise that's
>> actually in the master, or these DACs are particularly
>> jitter-prone.
good to read that someone else also experienced the same on badly recorded/pressed CDs! when I was writing my response post to Undertow, exactly the same thought crossed my mind. These non oversampling DACs use a Crystal Semi 8412 or 8414 I.C. that uses a PLL to extract & lock onto the CDP clock. This is much different than most other hi-end systems that lock the CDP to the DAC clock, which is a more stable/less jitter clock. If these badly recorded CDs must have lots of noise in them, it *could* push the PLL to edges of its lock range, which could have the same effect as high jitter.

>> 04-02-06: Islandflyfisher
>> I think it’s all about error correction. A CD transport
>> can only do so much. Near perfect CD error correction
>> for today PC is a simple process for them.
sorry to burst your bubble, dude, but it's not all about error correction!
In another A'gon thread we've have been thru this - even the most economical CDPs & DVD players have good enough laser pick-ups systems to read the CD w/ near-100% accuracy. The error correction you are talking about are CRC & Reed-Solomon type error correction codes used to correct bits as they are read off the CD. Error correction is generally not used elsewhere in the CD/DVD player.

What is probably happening in your case (w/ the PC server) is that you are lending credence to Hudsonhawk's theory of these non OS DACs being jitter prone. It is well-known fact that ripping a CD to one's hard-drive before burning it to CD-R or playing it back on one's stereo is a good method to reduce jitter - the hard-drive dumps the data to a FIFO & the sound-card reads it using a much more stable clock.
Good for you Hudsonhawk! Glad to see the NON OS DAC working out for you.

Good listening!
I also did some thinking about your comparison of the SN DAC and the Wadia. I'm thinking that some of the differences you were hearing had a lot to do with the output impedance of the Wadia (51 ohms) verses the SN DAC ( guessing maybe 3000 ohms). The input of your Preamp is 50K ohms I think?

The Wadia should sound more dynamic and linear..I'm guessing. The differences you described between the units. I also noticed when using or not using a buffer between my DAC and integrated. The buffer which I believe your player has built in, gives more presence and makes the musical lines easier to follow.

This is why in IMHO..unless you have a cd player or DAC with analog outputs of the Wadia's caliber or a Preamp with a high input impedance ..say 100K ohms. A buffer is mandatory to get the most out of the DAC or CD players analog outputs.

I also believe this is one of the reasons many love PC audio. Some of the sound cards used have an output impedance of 50 Ohms.
>> 04-02-06: Gmood1
>> Bombaywalla,
>> .......I'm thinking that some of the differences you
>> were hearing had a lot to do with the output impedance
>> of the Wadia (51 ohms) verses the SN DAC ( guessing
>> maybe 3000 ohms).

Gmood1, I'm having a hard time believing this. Off the top of my head, I don't know what the input impedance of my preamp is, but I think that your guess of 50K is pretty damn good one. I'll have to look in the user's manual where it is stated.
AFAIK, if the input impedance to the next stage is 10X higher than that of the prev stage, the input imp gets defined by the prev/driving stage (in this case the DAC output). Thus, both 50 Ohms & 3K Ohms are small enough for an input imp of 50K.
The SN Saru DAC+ uses Burr-Brown OPA627 buffers. I briefly looked at the TDA1543 DAC spec page & if I read it correctly, it's a current o/p DAC. So, these OPA627 buffers must be doing a dual job of current->voltage conversion + buffering. There has simply got to be feedback around these OPA627 opamps (in the wcs, it's being operated as a unity gain buffer) in which case, the opamp's buffer o/p impedance gets divided by the OPA627's open loop gain. This DC gain is usually very high implying that the (closed loop) o/p impedance must be very small (less than 1 Ohm).
A long way of saying that I don't believe that o/p imp has anything to do w/ the sound difference.

>> The buffer which I believe your player has built in,
>> gives more presence and makes the musical lines easier
>> to follow.
This makes sense - the TDA1543 DAC does not have the capability to drive the interconnect cable + preamp input in terms of creating enough voltage swing at the preamp input. It just wasn't designed for that! Hence, the need for a buffer. The component values in feedback network for the buffer need to be carefully selected so that they do not load the TDA1543 o/p. Additionally, overall thermal noise from resistors also needs to be considered.

>> I also believe this is one of the reasons many love PC
>> audio. Some of the sound cards used have an output
>> impedance of 50 Ohms.
I don't know much about PC sound cards. Somebody w/ more experience can confirm or not whether the o/p impedance is 50 Ohms or not.

However, unless I see a good reason to contradict, I believe that Hudsonhawk is on the right track w/ his hypothesis of the sound diff - the clock jitter.
As I wrote in my prev post - the Crystal Semi 8412/8414 locks onto the recovered clock embedded in the digital data stream using an on-chip digital PLL. The o/p clock from the 8412/8414 cannot be any cleaner (jitter-wise) than what is fed into it. Hence, the clock to the TDA1543 sample & hold ckt is a jittery clock (esp for badly recorded CDs). This will certainly create D->A errors resulting in "digital" sound. The more I think about this issue, the more I'm convinced that this is the issue. If there is someone out there that thinks I'm wrong, please correct me.

One thing that could be done to alleviate this issue (& higher-priced DACs like Audio Note, etc might be doing) is to create a very low jitter clock ref for the DAC (say, using the Tent XO module or something similar). It can be 44.1KHz or 48KHz or 88.2KHz or 96KHz. Then, using the Crystal Semi 8412/8414 to lock onto the embedded clock in the data stream, dump the incoming data into a FIFO at the CD transport clock rate. Then, using the low-jitter DAC clock, clock the data out from the FIFO into the DAC. This separates the CD transport noisy & jittery clock from the DAC clock. The sound o/p must improve dramatically.

Look at a sound card - I think that you'll see a clock/crystal on that PCB! it is clocking the data into its buffers from the PC hard-drive using that clock & non OS DAC is locking onto that clean clock. Hence, the sound o/p is much better. Bet you, that's what happening!

Yes Bombaywalla the 10x factor works OK. I'm not sure this is written in stone though. After listening to the differences of the average CD player or DAC output impedance (which is around 3000 ohms)verses using a separate buffer(100k ohm input and 16 ohms output at the moment) to alleviate the load of the interconnect and the amplifier. There is more dynamics,deeper tighter bass and the images are more defined. It's almost like some one took the governor off and let the engine run without it being held back.

This is using a 25K passive volume control in the loop.I should have mentioned passive volume controls. You can hear the differences very easily.

I'm not as technically oriented as you are my friend. In layman terms, it's like using a CD player that is designed to run directly into an amplifier. Then running it through a linestage/buffer before the amplifier. Most would prefer the linestage/buffer to just the straight connection. Even though there's an additional component in the sure sounds better with that buffer in between.

One means to measure output impedance of a CD player, with close results, is to have a test CD with a 1Khz signal, play it and measure the open unloaded, output signal on a good AC voltmeter. Then add a variable resistance across it, adjust it until the value is half of the open measurement, remove this resistance and measure its resistance with a standard ohmmeter. That value should be very close to the source impedance, at least at 1Khz.

I've tried the BVaudio SR10 buffer unit in the past.This was done using analog outputs not as high grade as your Wadia. The difference was noticeable. When I moved to a more substantial buffer. The difference was unbelievable! Maybe this website can explain it better than I can BVaudio . By the way my TDA1543 based DAC doesn't use Op amps at all.