Originally Posted by Somewhatlost
wow, $550... for what is effectively snake oil... guess one would need that to go with their $1000/ft cables & magic pixie dusted AC power cord...and my personal favorite, the AC audiophile wall plate
...This new ultra clean low jitter signal
so can anyone actually explain why/how jitter is bad??here is a nice study about jitter
, for anyone who cares...
SWL, I'm not going to go too far down this rabbit-hole with you, because audio performance, both real and perceived, and whether both can be argued to show value, can be debated endlessly. I will simply say this: the whole is sometimes more than the sum of the parts; or, there's more to a DAC than just its numbers.
Here's some info, I was actually looking at in regards to another post, that I think argues my point; it's from PS Audio, in regards to their DLIII (which I happen to use):The receiver in a DAC is a critical component. It takes the serial data stream (everything in one straight line of data) and converts it to a parallel stream and separates out the clock. This function is the first place a DAC can make or break the way it performs, and here we used the hottest new receiver on the market, the 192kHz Crystal CS8416 with its extremely low-jitter performance (around 50 ps after we reclock it later in the process).
Once the data has been separated by the receiver, it’s sent to the astounding TI SRC4192 high-end sample rate converter. Now here, regardless of the original sample rate your USB, SPDIF or Optical source has (typically 44kHz) we take the data and upsample it to 192kHz. The TI device is the finest made today and maintains low distortion during the upsample process.
The output stage is the key. Once the sample rate has been converted, it is sent to the TI PCM1798 balanced DAC and its output is fed into our unique output stage.
DAC’s convert the digital signal into current. Unfortunately, to play music through our systems, we need voltage. So the first job of the all important output stage is to convert the current output of the DAC to a voltage, then amplify it so our preamplifier can play it back through the power amp.
99% of every DAC on the planet uses an op-amp to convert the output of the DAC to a voltage. We learned years ago that this is the worst thing you can do for the sound, because op-amps all have two major problems when used for this function: feedback and speed issues.
Without getting too technical, the greatest opportunity for a bright and edgy “digital” sound is caused by op-amp based current to voltage converters (IV converters) because the high speed of the DAC’s output causes transient or slewing induced distortion in the op-amps (SID). SID is a combination of feedback and transient response issues that some exotic high-speed op amps can come close to handling, but all have a problem with it.
PS Audio’s engineers avoid the SID harshness by eliminating the feedback of the IV stage. We do this by a unique single transistor IV converter with no feedback. Speed issues and SID issues are completely eliminated with this technique.
Once the signal has been converted to a voltage, the next potential sonic weakness is found in the filtering. All DAC’s produce switching noise that must be eliminated before it reaches your preamp/amp combination. Most companies use a gain stage with active feedback filtering. The problem with this approach is somewhat the same as we just encountered with the IV converter, feedback and speed issues.
To solve this, PS Engineering uses a passive first stage filter to lower the noise before it enters the gain stage. This is a simple technique that completely eliminates the hardness associated with active filtering.
Next to last, the gain stage itself which boosts the output of the DAC to the standard line level output required to play music. For this challenge, PS Engineers stayed away from op-amps yet again, and built a 100% class A discrete FET based output stage. This high-end stage uses sweet sounding FET’s at the input and low noise powerful bipolar transistors for the gain and output stage.
Everything is direct coupled between the DAC output and the DLIII output so bass is stunning in its power and impact.
Last, but certainly not least, is the power supply. Everything we do to help the sonics of our product be the best in the world would be for naught if we had a small power supply. We’ve seen everything from the wall mounted transformer supplies (shudder) to power amp size power supplies. Bottom line is this: if you want high-end performance you need a high-end power supply.
Inside the DLIII is a huge transformer, coupled to many thousands of microfarads of capacitance, Linear Technologies regulators and high speed, low noise diodes.
Now, is this marketing from PS Audio, to try and taught their products as superior...of course. But it doesn't mean it isn't grounded in engineering fact. Doesn't mean that it is
either; I'm not an engineer and I don't claim to know what any of that means. You might say "well they take advantage of the fact that I don't know anything to convince me that it's "better" when it isn't" and I might respond "they take advantage of the fact that I don't know anything, to educate me
, and convince me that it's "better"...and it is
". There's an argument to be made on both sides. You probably couldn't even get two engineers to always agree.
But let's stop just quoting jitter numbers, and what's audible and not, as the end-all, be-all criteria for judging how a digital device sounds
. Some believe there's more to it than the DAC, more to it than the jitter, and if the Cullen mod, which is what we're talking about in particular, improves the parts in the path of signal processing, well...like the PS Audio article articulates, that may make a world of difference.
I'm not an absolute believer myself. You'll see that my language reflects that I am on the fence when it comes to some of this stuff. I take everything on a case-by-case basis; do I think an external
DAC, that was built for the sole purpose of digial-to-analog conversions, and uses high quality parts, because it was built to hit a 4-figure price-point, is likely to outperform the one that is included
in a device (such as either the SB or
Sonos), that does many other things, and is built to hit a very competitive and specific price-point of $150 (or $250 or $350)? Yes.
Do I think even a $50 aftermarket power cable might enable a 5-figure amp to draw cleaner power than the $0.50 throw-away black cord that they toss into every electronics box? Sure, why not. Do I think a $500 power does 10-times the job? Me, no. But all this stuff is really, really subjective, and there can be an argument made for both sides. If it's not your bag, that's fine; maybe someone in another forum makes fun of you because you think you're justified in spending 6-figures on a Porsche, when that poster can drive 65, just like you, for much less. It's the very nature of hobbies and enthusiasms. Don't just dismiss them with the knee-jerk reaction that everything you don't believe in must be "snake oil".