Pathetic. AKM knows their stuff and although I tested a number of other output topologies, their recommended design performed by far the best with this particular DAC. However, Transporter is by no means a "verbatim" copy of the eval board. The power supplies (jung regs), passive components (metal film resistors, polyethylene caps), and clock circuitry are quite different which is why Transporter outperforms the AKM eval design by quite a wide margin.
Yes, the eval design is supposed to be cost effective but that dos not mean you can just make it better by swapping a part here or there. In fact, randomly swapping out caps and op-amps is very dangerous. People think higher bandwidth opamps are good but they quite often just add more hash into the noise floor for zero improvement in the audible band. JRC's 5534s have extremely good noise rejection and you would be hard pressed to find an op amp that performs better in this ciruit. Also, active coupling circuits, or other types of coupling caps, were found in my testing to only increase harmonic distortion in the low end and/or impair SNR at the high end. I would challenge any of these modders to try some simple side-by-side measurements against the original product so we can all see what is actually happening. Or if someone really does improve the product with simple component swapping, then I would be happy to eat my hat and consider incorporating those changes in the product. I don't have a problem with modding for fun and educational value, but to claim that the original design sucks because op-amps aren't expensive enough is just ignorant. We design these products for real performance that you can hear, not the "gee whiz lookee all those big caps" factor. -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=41065 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
