glowing review:
http://www.witchdoctor.co.nz/index.php/2013/06/line-magnetic-lm-502ca-vacuum-tube-dac-review/
“Shindo of China” lol
some thoughts from Thorsten Loesch (he of AMR fame,
http://www.amr-audio.co.uk/html/product_list.html on JoeNet
http://mailman.soundlist.org/mailman/listinfo/sound< Had a look.
> 1 , using the U.S. ESS 9016 DAC chip
The ESS Chip's CAN be quite good, but they are not easy to implement right.
The problem is that DAC inside switches at an extremely high rate and
has no internal analogue filtering to slow things down, so the output
switches state at the external clock, usually 80MHz - 125MHz. There
are few options for analogue stages that stand the slightest chance to
deal with such a signal without getting out of shape.
The best implementation I know uses low value I/V conversion
resistors, followed by a high ratio stepup transformer also used as
lowpass filter, followed by some tube buffers. This is not a
commercial product BTW.
> 10 , transistor output op amp circuit using advanced ceramics NE5532, tube output circuit uses two 12AU7
The 5532 is really not an op-amp to deal with high rate unfiltered signals.
Maybe their tube section is better, unless of course it is just a
cathode follower.
Seeing the SNR they get from the ES9016 indicates a serious design problem.
It is easily possibly to exceed 120dB SNR using this DAC, only getting
98dB on the Op-Amp based output is poor. Possibly it is down to
ultrasonic noise and RFI from the DAC chip folding back into the audio
range.
Now how much does this say about what it will sound like to you? Not much.
But given what is there objectively I would strongly advise to listen
for oneself and not to buy blind, at least not without a solid 30 day
"no quibble" return policy. >
regards