Raspberry Pi I2S to SPDIF Hat

haha

There are plenty of CPU's, micro controllers, chips in CD spinners, running slower then (pi) and at times in the same bandwidth as the digital audio signals, so still plenty to deal with there, like we are now in regards to power & filtering.

The Teac is a $4000 transport, they probably built the CD mechanism, and they paid attention to the digital out implementation.

I really don't want to lug around a 90's spinner, do you? They ain't that special.

So yeah, the problem may come down to the pi & it's i2s, and the os--- we shall see... will be fun to play with the D2 prototype!

 

cool, we need piCorePlayer going also... it's pretty slick how it completely runs from ram, and you can basically reduce it down to a single process, that practically simply moves PCM to the GPIO pins (i2s)...

 

Why would a Gungnir Multibit be useful?

If by usb power you mean using the usb port, there is no need to send the 5V to the gpio. You could just put the jumper and feed the speed2 that will pass it to the Pi bypassing the fuse from usb. But you'll lose speed2\Pi isolation. Or can you suggest a different way?

 

Guess I meant... interesting. Haven't listened to one yet but from discussion about it (and multibit in general) they are really detailed... also you did not seem to like it. So to try this new front end on it would be cool.

I mean keep the jumper off, and power it thru gpio with the additional LPS.

 

I have a Yggdrasil I'll be testing with the SPD2 (both AES and BNC), and will be testing with separate power supplies for each section

 

Awesome, are you def on the list for a prototype? Didn't see you on @Michael Kelly's list posted awhile ago.

Do you have anything that can turn on it's VCXO/VCO warning light -- such as a stock digi+ perhaps?

 

done

 

BNC is the original spec, it maintains a perfect 75Ohm thru the connection, and in general it's a really precise connection, that's why it's used in measurement gear like oscilloscopes.

RCA is just used as convenience and simplicity, it's always been compromised slightly.

Even XLR was added later for long PRO runs, where you actually need it, it hangs around because it's assumed "high-end" 'cause it "looks" like balanced connections on amps/pre-amps. So not better then BNC necessarily.

All you need is this however, if you do not have a BNC digital cable:

 

The Gun/Yggdrasil has BNC.

Why PSAudio doesn't use it is beyond me, however ethernet or i2s seems ideal for their Dac. But even they are dicking around with USB, i.e. that LANRover .

My cullenIV PSAudio Dac has BNC w/an isolation transformer.

 

All good points about BNC and I wish more gear had it. But what I was getting at is that you can't actually use BNC unless your DAC has BNC. Or is it just as good to use a BNC to RCA adapter? So what category of gear does have BNC? Only high end DACs? Pro gear?

 

Jason at Schiit said very few things activate the VCO light. One is satellite receivers and the other is the Apple Airport.

Although I would like to know if the Gungnir Multibit/Yggdrasil minimizes the differences in sound that @Vastx observed between his CD player and the Pi2design card. The reclocking in those DACs should clean up the signal quite a bit.

 

I'm so sorry... that marketing and real life are so different things
I didn't have the pi2design card at the time I had the Gungnir Multibit home but don't make mistake, a good transport made the difference with Gungnir Multibit as much as with other dacs.

 

Yep, too bad it's not standard. I'm testing the Moby now & have to use RCA on the Dac side, no big deal-- it is what it is. All the in/outs, sender/reciever problems can add up.

The BlackCat cable I'm using here came with bnc/rca adapters which is nice.

 

Yup, I'm on the second round list for a prototype board.

I have an old HD-DVD player that may activate the VCO light, but I haven't tested it in that manner yet.

 

cool, do you like the Yggdrasil? I have about 20 tabs open researching it

please try the old player... curious about it, if it is on try listening to it!

 

I like it very much! Extremely detailed, yet very smooth sounding.

I'll give the old player a try in comparison to the SPD2 later down the road when I have everything set up and am doing comparisons.

 

nice!

Ok, sounds like a plan... kinda thinking no SPD2's for us... have to wait for the final product.

 

Guys - apologies for the silent treatment! We are in the middle of moving the company and I have been unable to get the SPD2 batch on the bench for test. I do plan to wrap it up as I moved my office and lab setup last week. Give me another week to sort my brain out.

Vastx - Have you tried the patch to allow clock switching? This eliminates the PLL as a source of jitter. Maybe that closes the Teac/Pi+SPD2 gap a bit more? Other than the clocks, there is nothing functionally that can be done. If there is still a difference it may simply be due to the small amount of jitter that remains and whatever residual PSU noise there is. I will admit that this design was done based on my experience and best practices from that. Not from a pure audio perspective.

Cheers,
Michael

 

Hi Micheal,
I used the provided volumio image and I followed the instructions. I assume I already used the clock switching. As for the psu residual noise, I used a 2 rail 5v lpsu with LT3042... so I guess the PSU noise should be very low.

@Scott Kramer I tried AES\EBU and indeed it feels a litlle better than coax. But the difference is still marginal compared to the gap versus the teac cd spinner.

 

Yes, the Volumio we sent has the clock switching. For some reason I thought you had picore player.

Cheers,
Michael