"How can the DAC be 21 bit if the chips are 20 bit?"
It can’t. John Atkinson review of the DAC clearly states that while the analog performance is excellent, the digital performance is less than desirable especially on high signal levels (which is the majority of pop rock music).
I wouldn’t want this DAC but I understand many here do not care about measured performance as long as they like the sound. |
@defiantboomerang
Yes but I would say most audiophiles are dining on delicious gastronomic meals full of flavor and expensive ingredients rather than junk food.
I am interested in the accurate reproduction of the source file or music as produced by the artist and their engineers/producer but I fully appreciate why others like things to sound the way they want. After all at a restaurant you often order the dishes that you like best not necessarily what the chef has specially prepared.
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You can still get some signal resolution above 20 bits by dithering the 24 bit digital signal when converting to 20 bit. Dithering is much preferred to just truncating the least significant bits. Dithering adds random noise to the signal and raises the S/N but it will preserve some signal below the LSB. Studios do this all the time when taking 24 bit Masters and producing a 16 bit CD.
I think Schiit are using the same logic as Meridan in saying that the last 3 bits on 24 bits is just noise (below current analog dynamic range resolution which is about 21 bit equivalent). This is true on a full scale signal. However a good recording may not use all full scale 24 bits so the last 4 bits could very well be within analog performance range and it is bad design to say we just throw them away. Also dithering is a form of processing and compression and just like with lossy audio and photo compression - some algorithms are bettter then others.
Do do you trust your DAC manufacturer to process and massage the incoming 24 bit audio and throw away 4 bits or do you prefer to hear what the studio mastering engineer carefully produced? |
Putting one chip on -ve and one chip on +ve of balanced will simply double the voltage but won’t increase the bit depth. There really is no way to increase bit depth without a DAC chip with greater bit depth so I think Schiit is stretching the truth. I think that they are trying to say there is still signal below 20 bit due to dithering (random noise) that they must add prior to bit truncation of the last 4 bits of the 24 bit input signal. If they don't have the processing power to do dithering (normally done on a computer) then the audio quality will be compromised. |
@almarg
Not really. This just doubles the voltage value of each bit but it keeps the same resolution in terms as of number of bits or number of unique digital values available.
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@defiantboomerang
What you propose is indeed 21 bit. 20 bits from the two DACs each and an additional one bit MSB logic chip which controls whether the two DACs are additive or only one is turned on. This is not the same as balanced where both chips are operating simultaneously and are always on.
I would call this a hybrid DAC - in fact using this topology you could take eight 16 bit DACs and couple them together with an 8 bit logic chip to create a 24 bit DAC.
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@almarg
Yes. I did understand your post.
Glad we both agree that you can't magically get 21 bits from a 20 bit DAC without ADDITIONAL digital control (the extra bit) which then makes the DAC a 21 bit DAC not a 20 bit DAC. If you had added the extra MSB digital logic control explicitly then I would have understood beter what you were driving at.
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@georgehifi
If playing CD quality files it really doesn't matter at all. Good point.
However in judging a product I do like to check manufacturers claims. For example technical claims by Hegel don't hold water. So either they got something messed up in translation from Norwegian or I have my doubts over technical competence. |
@bacobits1
I think it is reference to Robert Harley, Absolute Sound. |
@mmeysarosh
Good points about performance measurements. I was surprised about the DAC3. I didn’t expect to hear a difference but I believe I could. It wasnt a difference in sound but more akin to better blacks on a TV - the sound popped out of the background in more detail. Not sure I could detect this in blind A and B tests - definitely subtle. I believe the performance in many of the latest DACs is on a similar excellent par. My speakers have THD distortion below -65 dB across the spectrum and also can play cleanly up to about 120 dB SPL which helps to discern such small improvements at low signal levels.
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@defiantboomerang ATC EL150ASL which is the more aesthetically pleasing elliptical version of the much more affordable ATC SCM 150 ASL big box studio monitor. ATC have been successful at selling pro studio main monitors for over 30 years. These are like a microscope on the recording and not something most people would be seeking for home listening. Client list http://atcloudspeakers.co.uk/client-list/my setup https://systems.audiogon.com/systems/6257 |
@defiantboomerang
The speakers are active - 6 poweramps one for each transducer so I don’t need a power amp for this model.
@mmeysarosh
I believe ATC claim that a single ATC 300 cabinet will deliver an astonishing 121 dB SPL at less than .3% THD (with 10dB of headroom). The 300 cabinet is the same build as mine except for two 15" woofers per speaker instead of one (300 litre volume cabinet instead of 150 litre). So 117 dB SPL for one of my speakers at 1 meter sounds about right.
... please direct further questions on my system thread as I don’t think it appropriate to continue to discuss ATC speakers further on a thread that is specifically about Schiit’s excellent Yggdrasil DAC. I prefer not to hijack this thread. |
Back to Yggdrasil, my worst fears as posted above are true.
I found this statement in Stereophile
"When you have 24-bit data but 20-bit DACs, you need to dither those data to match the DAC. Otherwise, simply chopping off the 4 LSBs, called "truncation," reintroduces quantizing distortion. Schiit’s Jason Stoddard has subsequently said that the Yggdrasil "rounds" 24-bit data but my measurements suggest that the LSBs of 24-bit data are simply truncated.
John Atkinson
Editor, Stereophile"
This is a disaster. Every studio mastering engineer will carefully dither high resolution 24 bit data when converting to 16 bit lower (bit depth). This is in order to reduce quantization noise! This is not optional - This is industry best practice! If JA is to be believed Schiit do NOT understand digital signal processing at all - they just truncate the data!!! They may be geniuses at headphone amplifiers and analog circuits but this product is a failure if you are interested in high fidelity.
Be warned - this DAC should only be used with files that are 20 bit or less. If you use a PC for playback to this DAC then I would recommend doing a proper dithered conversion of 24 bit source files to 20 bit on the PC prior to sending to this DAC as it will sound much better. Programs like Audacity can do this conversion for you.
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If you watch the video you will see that rounding is practically the same as truncation and does similar damage.
Sorry but Schiit don’t understand what they are doing. This is common when good designers with a strong background in analog design start making digital components. |
@almarg
As always I agree with pretty much all your comments.
I would add that the 24 bit will always look much better because at the same -90dbfs you have more bits to characterize the signal. The 16 bit looks square because there are only 2 bits to describe the signal. Even with a 20 bit DAC there are 6 bits available to characterize the sinewave at 24bit (so it looks smooth).
The zero crossing errors are the most alarming in those particular measurements.
"Audibly insignificant" depends so much on the frequencies. Low level noise distributed evenly and randomly across the spectrum is harmless. Rounding or Truncation can lead to high frequency noise of distinct tones which is harmful even at low levels which is why studios go to lengths to dither digital when reducing bit depth.
JA notes the jitter performance is less than desirable also. There has been much importance given to jitter even though it is very very low level noise - and this is because non-random jitter creates distinct tones that are not harmonically related to the music.
What is actually audible as distortion is very much related to tone and frequency rather than purely a signal level. |
I would hazard a guess that for several reasons (only 20 bit, R2R and no upsampling), by necessity the filtering in this DAC will be close to Nyquist and therefore quite aggressive or sharp (like Non upsampling CD players). I suspect it is this smoother sound from filtered highs and the fantastic analog section that makes this DAC so musical and desirable to some folks over competing ESS 9018 and 9028 style DACs.
Measurements only validate accuracy or high fidelity capability of a device. The musicality aspects are all in the ear of the beholder.
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@gdhal
The Oppo UDP 205 is indeed outstanding and I expect that it sounds a bit brighter and thinner than the Yggy. It may well outperform the DAC3 as you claim. Perhaps the Oppo UDP 205 will be another Class A or A+ Stereophile recommended player. Per JA above, we can easily surmise why the Yggy is not.
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+1 Almarg - I agree that the statement in the link is rather ambiguous. It isnt clear if it really is greater resolution from the greater bit depth of an additional bit or just a higher signal per bit but still 20 bits...
Summing 20 bits + 20 bits is still 20 bit levels as it is simply double the voltage value per bit compared to a single 20 but DAC chip. |
