AudioSector-chip amp kits, dacs, chassis

[jleaman]

Originally posted by Thomas B
Hi Karma, you're saying A but not B. Please elaborate. You got me really curious.

Hi Dave, right, software is wide open. But I am mostly talking about physical components. Mobo, cpu, storage, casework. Mac Mini is wide shut. You have to break it open with a knife. Make no mistake, I own Quicksilver Mac, Cinema Display, PowerBook. iBook, iPod, iShuffle, etc, I love Macs. But for computer audio I think the PC camp is leading the way right now. People who's been comparing Mac to PC's agree, PC's are holding an edge in terms of sound quality. That can rapidly change, of course. Mac software still need to be more adapted to high end audio applications though.

/Thomas B

Running windows and keeping it up todate and doing drivers is a pain in the A$$ a mac mini out of the box is already done and works. Plus it is more silent than a pc smaller than a pc and NICER LOOKING than a pc.. Me being daves side kick doing all the mac work ( well helping ) im a mac / pc tech if i were to switch to pc audio witch i wont id go for a mac mini.

[hayenc]

If this thread is in Vendor's Bazaar for Peter Daniel's work, why is there a Mac discussion going on?

[karma]

lol im not using winblows or mac os so im not taking sides

[planet10]

Originally posted by hayenc
If this thread is in Vendor's Bazaar for Peter Daniel's work, why is there a Mac discussion going on?

USB DACs... a FireWire DAC would be even better. Computer's have HUGE potential as transports becasue the ripping process doesn't have to happen in real-time, the computer can take as long as it needs to get every bit off the disk. Then it is streamed thru a RAM buffer on output.

My current USB DAC is just adequate to get music to my amp so i have been following the USB DAC thing closely. Brent has been working on one, but a PD unit would be a no-brainer. I'm not likely to afford the one i've been salivating over -- even the budget one. PDs being a kit should be no problem adding a cathode follower output stage to it so as to guild the lily.

Peter, have you seen the Stereophile article on the Brick?

dave

[Peter Daniel]

Yes, I've seen it and it was actually my other motivation to try USB interface

[karma]

hmm that was a good read, i see how usb is better than digital out.

peter is this going to be somthing that can be added to the dacs
we have or would it be a new one alltogether?

[rjkdivin]

Originally posted by Peter Daniel


The DAC phase can be corrected (to non reversing). You simply need to reverse the connection of two traces from input buffer chip to the receiver. The next board version will have it corrected, I'm also working on optional USB interface.

Peter,

Would there be a problem with using a simple DPDT switch to be able to select between reversing and non-reversing?

Robert

[metalman]

Peter,

I am curios about your choice of the PCM2707. Everyone else building usb dacs has been focusing on either the 2702 ar 2902. You aren't one to make casual decisions, so I'd be interested to here your rationale.

One thing to note though, the reading I have been doing lately has been very contrary to Gordon Rankin's claims, specifically a usb interface can easily produce a jitter contaminated signal. There are very good reasons why the Burr-Brown boys spent so much time developing their line of usb-dac chips. While his usb-dac products by all accounts perform exceptionally well, Rankin is throwing around some seriously misleading marketing hype. The accurate statement would be that the usb interface is free from source related jitter, but poor dac design can still add its own jitter contribution.

Lastly Peter, what do I have to do to cajole you into adding a balanced-out option to one of your dac. Please, pretty please

Cheers, Terry

[Peter Daniel]

Originally posted by karma
is this going to be somthing that can be added to the dacs
we have or would it be a new one alltogether?

I'm still not sure, I will see how it'll work out, but add on board would probably be more practical.

Originally posted by rjkdivin
Would there be a problem with using a simple DPDT switch to be able to select between reversing and non-reversing?

It should work, but I'm not sure how well. This is a sensitive area of the circuit and any switching of that sort should be rather avoided, but if you need that feature, why not give it a try.

Originally posted by metalman
I am curios about your choice of the PCM2707. Everyone else building usb dacs has been focusing on either the 2702 ar 2902. You aren't one to make casual decisions, so I'd be interested to here your rationale.

One thing to note though, the reading I have been doing lately has been very contrary to Gordon Rankin's claims, specifically a usb interface can easily produce a jitter contaminated signal. There are very good reasons why the Burr-Brown boys spent so much time developing their line of usb-dac chips. While his usb-dac products by all accounts perform exceptionally well, Rankin is throwing around some seriously misleading marketing hype. The accurate statement would be that the usb interface is free from source related jitter, but poor dac design can still add its own jitter contribution.

Lastly Peter, what do I have to do to cajole you into adding a balanced-out option to one of your dac. Please, pretty please

PCM2707 was not my choice. I got evaluation board (and some other items) from Brent, so it was his choice. He did a lot research in that area and I will just see initially how well it works. I'm still waiting for a laptop I bought for that purpose.

Jitter is surely important, but it's not the only issue of a good sounding DAC.

Lastly, implementing a balanced version of a DAC is very easy. You will need two boards, and on one of them instead of receiver install a chip that reverses data signal and feed it to the other DAC chip. If I'm not mistaken, stefanobilliani is using TDA1543 in that way and he gets pretty good results. I just didn't have time yet to try it. Besides, Elso mentioned he didn't like the DAC in a balanced setup

[Brent Welke]

The reason for using the PCM2706/7 over the PCM2702/4 is to remove SPDIF from the DAC. The PCM2706/7 has a I2S output that directly connects to the TDA1543 DAC chip. Otherwise the two chips are the same.

Kiss SPDIF good bye!

Another thing to consider is that with the current SPDIF dac you need an expensive transport to get the most out of it. Not the case with USB. Any computer that has USB 1.1 port will do. Old laptops become very useful.

I don't have any fancy transport here. I am waiting for Peter to compare the USB-->IS2 adapter to his fancy transports. I hope Peter will make a USB version if all goes well.

A USB adapter boards can be made for existing SPDIF dacs. My prototype adapter has a 8 pin socket. You pull the TDA1543 chip out the socket on the DAC, pop it into this socket then place this socket on top of the socket on the DAC. So it becomes a bit of a socket tower. But there you go, no soldering. Once that is working you can get better sound by suppling the adapter board with the 5 volts that would otherwise be powering the receiver chip.

Also see this tread for details of the PCM2706/7:
http://www.diyhifi.org/forums/viewtopic.php?p=7069#7069