Vintage DAC

[OnTheBlitz]

Another proof that newer isn't necessarily better.

You have to wonder if that F/W update was part of their "planned obsolescence". Most people would have just thrown it in the trash and bought the latest Apple product to replace it.

Good on the OP for getting it straightened out.

 

[foobarz]

Yamaha Natural Sound Field Processor DSP-3000, from 1987, probably counts as vintage. I'm still using mine as digital preamp (DAC + control amp to an M-65). It auto-senses and switches between 32k/44.1k/48k sample rates, 16-bit audio from my PC sound card. Input is coaxial S/PDIF only (has no optical). The DSP-3000 is also used as a simple control/pre-amplifier. It can also input an analog source (3-button inputs selector on front), and has a tape monitor. I don't use the sound field effects, and I have disabled them by pulling out the Dolby Surround circuit board and then bypassing the main audio to only the main output lines. So, the 4- or 6-channel mode select switch on the back does nothing. I did not want anything corrupting the sound of the mains. The LCD does not light up anymore. I would like to service/restore it, but I cannot find the DSP-3000 service manual. Like other old preamps that are good, it gets very warm and it has no ventilation openings! The electrolytic capacitors in it almost certainly need replacement.

 

[SterlingOne]

Well, I finally solved the problem and what a saga it was! I tested everything to rule things out and it all came back to the Airport Express (not the DAC, audio files, MacBook, cables, etc). What really tipped me off to the issue was that I got the identical crackling noise out of the analog output on the Airport as I did from the optical port. Long story short, the upgrade to firmware v7.8 is the source of the problem, and downgrading back down to 7.6.9 is the solution. The audio sounds crystal clear now, and I feel comfortable considering the Airport Express to be a quality "vintage DAC" in its own right. I hope this info helps someone! Links:

Firmware upgrade is the issue:
https://forums.macrumors.com/threads/airport-express-firmware-update-terrible.2134953/

How to roll back the firmware:
https://www.macobserver.com/tips/quick-tip/macos-roll-back-airport-basestation-firmware/

I have 3 means to music stored on my laptop, 1 wireless and the others wired: 1. Airport Express to prepro via S/PDIF, 2. Creative Sound Blaster X-FI HD up sampling all usb input to 24/96 and sending it to prepro via optical S/PDIF, and 3. OPPO-205 DAC up sampling all usb input to 24/192 and sending analog to prepro via RCA. All means sound awesome from iTunes set to Windows Audio Session and 24/192 output. Wireless does sometimes have a dropout or two when I am using the computer for multiple tasks or when I am streaming rather than listening to a download. In most cases 256k sounds spectacular but I sense that the OPPO interface yields the best results. At any rate, no jitter that I can discern. One more thing the ADC/ DAC in my circa 1992 Sony PCM-7010F DAT Recorder delivers the best sound of all, but I have not figured a way for it to be used as a stand alone DAC.