AMB Laboratories DIY Audio Forums

[amb]

Different use of ο1 will require different cable lengths, depending on the distance of the ο1 mounting location and where the clock is needed. But yes, I agree that the cable should be kept as short as possible. The simple one-screw mounting makes it more likely that such a location could be found in the unit. This is certainly true in the DCX2496.

As for the output series resistor, 10Ω-47Ω can be used. The DCX2496's stock clock circuit used 22Ω. You could use 22Ω or 33Ω if you wish.

[LV26]

I can recommend to use 2$ clock buffer for next revision (like CDCLVC1102)
http://www.digikey.com/product-detail/e ... ND/2342852
This allow isolate Crystek from transmission (RF cable) reflection and increase cable length .

[amb]

I had considered a clock buffer but left it out to keep things simpler, and because the clock output was intended to drive only one load. I'll revisit this idea if/when I do a new version.

[Pieterh]

Dear Ti,

Can I ask, would this fit and be a good upgrade for a Asrock Q1900-ITX Motherboard clock ? I use this motherboard in an audiostreamer on daphile and has sigma 11 LPS's and a paul pang v2 usb card.

Thanks, Pieter

[amb]

I don't know about the specifics of the motherboard you mention, but in general it makes no sense to use an ultra low jitter clock on the main CPU or other digital ancillaries on the motherboard. If you are using the motherboard's onboard audio and it has its own master clock, then maybe that clock could be upgraded. But on almost all motherboards, the onboard audio is so poor in quality that it's not worth a master clock upgrade. You're much better off using a good external USB DAC.

[Pieterh]

i use my mobo with audiostreamer software (daphile) and i send the pcm data to an external dac via a ppa v2 usb card. i dont use onboard audio. you have any clue why a recent and expensive audiostreamer by sound galleries music server (SGM) uses a high grade clock upgrade on their mobo (asus z170m-plus). they use their streamer also to upsample to e.g. dsd 512 with HQPlayer.

[amb]

you have any clue why a recent and expensive audiostreamer by sound galleries music server (SGM) uses a high grade clock upgrade on their mobo (asus z170m-plus). they use their streamer also to upsample to e.g. dsd 512 with HQPlayer.

Just because someone makes such a device and use it as a selling point doesn't necessarily make real sense. There are plenty of products out there that are designed based on flawed reasoning and hyped up to make you spend more money.

You will be running a multi-tasking operating system that schedules processes/threads in and out, read and write to memory and I/O devices, and handles interrupts which will cause any playing digital audio stream to be stopped and started continuously. A low jitter clock for the CPU won't do anything to help this. Only hardware buffering would alleviate data overrun and underrun conditions. This is the nature of things, and is why an external asynchronous USB DAC is superior than an adaptive USB DAC. The former controls the flow of data from the host to reduce jitter. Of course, having a low-jitter clock for the DAC itself is important.

[LV26]

SGM audiophile grade custom hardware
5 ppb stability OCXO with low noise power supply replacing the motherboard system clock
Low noise dual choke power supply for computer motherboard and CPU
Low noise, high frequency power supply for SSD
Mundorf Mlytic capacitors with 660,000 microfarads storage capacity
Steel potted power supply transformer with internal copper foil shielding
High performance RAM with custom aluminum heat sinks
Heatpipe cooling system for CPU connected to copper billet CNC milled heatsinks allowing fanless high load operation with CPU overclocking
Optimized BIOS settings for CPU and RAM

from http://soundgalleries.com/product/sgm-2015/

Really they do nothing except enclosure and some simplest electronics.

[Pieterh]

ok thanks for your reflections / arguments. i understand most of it. It brings me to another question, not sure this the right thread / place for that. how would the optimal pc-based audiostreamer look like based on your knowledge? mobo type, processor, memory, hdd, psu, special usb cards like sotm, jplay or paul pang? software?

thanks.

[LV26]

Using well and smart designed DAC (with ASRC/Reclocking) like γ3 you will have amazing result with simple notebook.