Some say “bits are bits” because when you copy a file or CD on your computer, all the “zeros” and “ones” are perfectly duplicated from source to destination, and it should not matter whether you use a $20 CD-Rom or a $20,000 high-end transport to read.
But when it comes to digital audio, it requires not only accurate reading of each bit, but also accurate timing between bits. The timing error, mostly known as “Jitter”, deteriorates digital sound from at least four causes:
(1) the transport/laser follow a clock chip’s timing instruction to get a reading from the CD (or from USB drive, or from network). If the clock chip is not precise, you have Jitter #1.
(2) when the transport/laser execute the reading, some mechanical variations (motor spin speed variations, network lag etc) will give you Jitter #2.
(3) when the transport sends digital signal to the DAC via SPDIF (Sony/Philips Digital InterFace), you get Jitter #3 because of the inherent problem with SPDIF protocol.
(4) when digital signal arrives the DAC, it is often filtered and re-shaped before D/A conversion. This process gives you Jitter #4.
By connecting a normal transport (such as a DVD player, a computer, or a streamer) to a normal DAC, you are listening to Jitter #1 + #2 + #3 + #4, which is a lot of Jitter. In different systems each jitter weights differently, but Unlike analog distortion, one Jitter cannot be cancelled out by another Jitter, it is normally magnified by subsequent jitter.
A Master clock such as Horae will reduce Jitter #1. Simply put, there’s no substitution for a good clock. Many audiophiles found clocks addictive, and indispensable once inserted into the playback chain. There are devices that accepts word clock, or master clock, we highly recommend an external master clock.
A heavy-duty CD transport, such as the VRDS NEO mechanism from Esoteric, will reduce Jitter #2. In the heyday of CD transports, different companies tried different strategies to build sturdy mechanisms, the “stable platter” from Pioneer, the “fixed laser pickup” from Sony, the “belt drive” from CEC are just a few examples of fundamental thinking, while more companies who lack the ability to build their own transport choose to strengthen after-market units with heavy sub-chassis, large disc pucks, and diffraction-reducing green lights.
By having the transport and DAC in one single box, you will reduce Jitter #3 by avoiding SPDIF. Some designers believe SPDIF is so evil that you should never have a separate DAC, and the way to avoid SPDIF is using I2S interface, which transfers the clock info intact, at least theoretically.
By using Field Programmable Gate Array (FPGA) and software-controlled algorithm, you will reduce Jitter #4 and overcome some problems embedded in a DAC chip. Some people prefer the sound of NOS DAC chips (PHILIPS TDA1543, for example) because they don’t “polute” the incoming signal as much as modern chips, which does a lot of filtering and upsampling.
Now with some deep understanding of Jitter, let’s look at some common strategies that have created myths in the past:
I have owned and sold a heavily modified Oppo 105, the $3000 modification replaced the solid state output stage with tubes, which doesn’t fix any of the above mentioned Jitter #1/2/3/4, it only tries to use the tube coloration to hide jittery digital sound.
Digital cables significantly change the sound because they “modify” Jitter #3, and adjust the amount of “SPDIF evil” without fixing it. So the “best” digital cable in my system may sound bad in yours.
Some people think having asynchronous DAC which buffers/reclocks the incoming digital signal will solve all the Jitter problem… however that’s just naive. In most cases the buffer reduces one jitter and adds another, in the end you have a different sound but not necessarily better sound.
With more and more audiophiles switching to streamer/server instead of a CD transport, many believe streamer/server sound better than spinning a silver disk. This is true only because a precision spinning mechanism is very expensive to build. But in a state-of-the-art system, all the digital sources, no matter you use streamer or server or transport, will benefit from a high-end master clock (Horae) in the input, and a high-end regenerator (Helen) in the output.
In an ideal setup, you’ll have:
Horae –> Transport/Server/Streamer –> Helen –> FPGA DAC
- Horae will minimize Jitter #1.
- A high-end Transport/Server/Streamer will minimize Jitter #2.
- Helen will minimize Jitter #3, especially via its I2S/SMA connection.
- FPGA DAC will minimize Jitter #4.
Thank you for reading this far, it does get complicated, doesn’t it? but there’s no way around if you want a SOTA digital system, which Titans Audio Lab is planning to provide.
Titans Audio Lab currently have two unique products, Helen and Horae available to audiophiles via its North America distributor Highlander Music & Entertainment Inc., in the future we plan to launch a full range of digital products including digital audio player, USB interface, and DAC.
We address the most fundamental technical problems in the digital audio playback chain, and provide the very best solution for the future. Our technical sources range from the cutting-edge silicon valley technology to the uber-precision Switzerland manufacturing, no cost has been spared in R&D and we don’t believe in snake oil. We are serious about digital audio, are you?