So when will the Chameleon be available? Or is it now?
post #811 of 1144
4/26/10 at 1:08am
Hi jkeny, welcome aboard, Ive got 24/96 out of the adum4160 which is plenty enough for the Chameleon nos dac. Most of us are 99.9% 16/44.1.
|The Adum4160, diyparadise Ultravox now replaces my Musiland usd 01, its simply does a better job at jitter reduction, and then some. So partnered to your modded Hiface could be something else, and higher rates are simply not a bottleneck here.
see pm for schematic. Michael at Teradak is very responsive to input from users, in fact thats why this dac exists at all, so who knows where this might go?
|The picture is of mid price nos dac, Chameleon, which has enormous potential. Very creative input on this thread, has produced a great dac, but more can be done on the data input side, yet its tricky to do that in a price range that comesurate with the dac. So thats where your modded hiface fits so nicely.|
|Bill would have to fill you in on Steve's input, as it is at present a strictly bespoke job. But I could see a modded hiface installed inside the Chameleon itself, if it can be figured out.|
|The difficulty is that the mod to add the I2S interface to the Chamelion is non-trivial. The board has very poor transmission-line characteristics as-is. This is evidently why the designer "scabbed-on" several ad-hoc terminators at various points in the net. An obvious lack of understanding of transmission-lines and termination techniques. As a result, quite a few traces are cut and 12 "blue-wires" are added to do the mod, as well as removing lots of terminations and changing one group. Even with these mods, the I2S driver at the source device, in this case the Pace-Car USB, must have serious drive strength in order to drive a parallel termination. If you have a PMC270X or something similar that you want to drive it with, it will not have enough drive, nor will it be 5V logic levels.
Also, I discovered that it craps-out after 96. You dont get 176 or 192.
Another thing that all of you must understand is that I2S done properly is not simply a matter of connecting the three signals and returns to the circuit. This configuration ignores the need for muting. This means that if you unplug the USB or I2S cables on your device or lose power to the device or the DAC, that a really loud pop can propagate to the speakers, causing potential amp and speaker damage.
This means that if you have this configuration, you must be very careful about connecting the I2S cable before powering anything on and then power-on the DAC last. Then power-down the DAC first.
If a reworker is interested in doing this I2S mod so that it is compatible with Off-Ramp or Pace-Car USB with 5V I2S output option, I can give this information freely. Just contact me.
If the OEM M2Tech I2S card could be modded for 5 volt output I have no doubt this would offer the "lowest cost" option for eliminating interface jitter on the Chameleon or Valab. But remember with just a USB input now we're talkin' computer audio only. Of coarse if you have the cash the Pace Car USB would still be the superior choice.
I sent the information about the OEM M2Tech board to Michael in the past but once again its a demand vs price point thing. However given the superiority of direct I2S input and looking at the simplicity in the pictures above ... there is a strong argument for a M2Tech I2S/USB input only version of the Chameleon.
jkeny, did you try your adum from 'circuits and home', yet on your modded hiface? I am very curious to see what this combination can do, isolation from pc and clean power to the clocks.
|My Blackgated Ultravox, running of a 12v SLA battery, has blown away the jittery hash and its not even async, just a psu.|
|Yes there is no doubt that your suggested option will bring a lot of improvement.
Even more would be garnered from a redesign of the input board on this dac, if a practical implemention of the modded hiface is via spidf and not I2S.