Muse Model 2

[rknize]

Someone gave me one of these. He gave up on it after having it repaired multiple times. It keeps blowing-up the input receiver chip. Not sure if it's a power supply issue or some problem with his setup.

I know it's pretty old school (CS8412/DF1700/PCM63K). Is it worth fixing? I have a couple of CS8412 chips, so that is not an issue. I wouldn't want to put it into service without figuring out the source of the problem first, though.

[Ken Newton]

The CS8412 performs at about as well as the current generation Cirrus DIR chip, the CS8416. The main differences are support for high-res. sample rates and multiple input sources. The DF1700 is probably no better or worse than most other half-band brickwall oversampling interpolation filters. The PCM63 DAC is extremely well regarded, with many audiophiles feeling it to subjectively be the pinnacle of audio DAC chip development. So, I say, yes, that Muse DAC is worth repairing.

Of course, you need to quickly get to the bottom of what is destroying the DIR chip.

[rknize]

Thanks for that. I'll put the power supplies on a scope to see if they misbehave at power up/down or something. I can't imagine what else it could be other than that or ESD from the inputs. The layout of the unit is very neat and tidy and the chassis is quite hefty. He's not tech savvy, so he didn't have much in the way of details. He did have a bag with a few dead CS8412 in it from the repair shop.

DACs are not exactly my forte. The unit only has single-ended AES inputs and I don't have any devices that put out straight AES. It sounds like it may work fine with S/PDIF and a suitable matching transformer, depending how picky the receiver is about the subtle protocol differences between the two. Is this the case?

[Ken Newton]

A single-ended (via RCA connector) AES input should be fully compatible with the S/PDIF output of any CD player, and without an interveneing transformer. If I correctly recall, the AES essentially adopted S/PDIF as a standard and call it AES3. I have to believe that the Muse DAC is intended to accept S/PDIF signal levels via it's single-ended input.

[rknize]

The inputs are BNC and are marked "AES/EBU". I think the main difference is in the voltage. S/PDIF is something like 0.5vpp and AES is 2-7Vpp.

[wwenze]

Computer sound cards particularly onboard ones like to output 5Vpp or 3.3Vpp for its SPDIF.

[rknize]

I'll see what mine do. Thanks.

[abraxalito]

Originally Posted by Ken Newton

The PCM63 DAC is extremely well regarded, with many audiophiles feeling it to subjectively be the pinnacle of audio DAC chip development.

I concur - if you were to read the datasheets carefully, and convert from dB to % where necessary you'd find that the rather aged PCM63-K bests the PCM1704-K in THD at -20dBFS.

[rknize]

Originally Posted by wwenze

Computer sound cards particularly onboard ones like to output 5Vpp or 3.3Vpp for its SPDIF.

You were right. The DAC was able to lock onto output from the sound card just fine. My SqueezeBox just doesn't put out enough amplitude, I guess.