Mr White's "Opus", designing a simple balanced DAC

[voodooless]

Any comments about my earlier suggestion:

Speaking about that: the USB board also has a SPDIF output. Would it be smart to link that to the new Wolfson SPDIF receiver, let it decently reclock there, and then let the data go to the DAC from there, in stead of directly linking the USB receiver to the DAC? My guess is that jitter might be reduced even further (the PCM2707 doesn't really say a lot about that though).

An added bonus might be that switching the SPDIF signal might be a lot easier that switching I2S.

 

[DarrenWadsworth]

What would you recc. for high quality (type of wire and gauge) to use as wiring between the:

cd-player and receiver
receiver and DAC
DAC and Balanced Output Sockets
power supply (yours) and components

Thank you
Darren

 

[BrianDonegan]

Here's what I use...

cd-player and receiver
Generic RCA cable that came with a receiver (rca to rca), then a small single pair from CAT5 cable (just cause I have a bunch)

receiver and DAC
some 24ga PVC wire I picked up (stranded)

DAC and Balanced Output Sockets
pairs from CAT5, re-wound into three wire sets instead of pairs (see reason above)
can be see here used with an embedded BETA Opus

power supply (yours) and components
some 24ga PVC wire I picked up (stranded)

 

[DarrenWadsworth]

I am building a Cd player from scratch, but am new to this.
I wanted to know where you think I should install the power switch.

Should I have it switch the HV before the transformers?
Have it Switch after the Transformers but before the PS?
Have it switch after the ps (before the DAC)?

Thank you
Darren

 

[Variac]

Before the transformers
Good Luck

 

[fierce_freak]

I've finally gotten around to doing some comparisons with the Opus. Against my Zhaolu D2.5a with a Zapfilter installed, I prefer the Opus in most cases, with the most common edge to the Zapfiltered Zhaolu being bass volume (not necesarrily quality). The Zhaolu might also do sax a little bit better, as well.

I don't have any buffer installed in my Opus at the moment...would adding something like the Zapfilter make the bass more present? My guess is that it would, but I'm relatively new to this

 

[BrianDonegan]

Are you using it with single-ended outputs?

 

[fierce_freak]

Balanced outs. The bass is there and is pretty good...I'm just a bit of a basshead

 

[jleaman]

I've finally gotten around to doing some comparisons with the Opus. Against my Zhaolu D2.5a with a Zapfilter installed, I prefer the Opus in most cases, with the most common edge to the Zapfiltered Zhaolu being bass volume (not necesarrily quality). The Zhaolu might also do sax a little bit better, as well.

I don't have any buffer installed in my Opus at the moment...would adding something like the Zapfilter make the bass more present? My guess is that it would, but I'm relatively new to this

Non secure webserver ?

 

[fierce_freak]

Huh?

Does anyone know where to source TORX? I need to add an optical input to my DAC but can't seem to find one of these anywhere. Also, can a simple DPDT switch be used to switch back and forth between coax and optical, or will I need a more complex circuit. Thanks, guys

 

[jleaman]

Huh?

pm me.

Jase

 

[BrianDonegan]

DigiKey stocks TORX connectors.


A switch would probably work fine. Might want to add a couple resistors to keep it clean.

 

[fierce_freak]

Ha, no wonder I missed it. I think I was searching for TORX179 Thanks, Brian.

 

[thomaseliot]

Working

Hi,

my two Opus arrived yesterday. Tonight I connected them to the two USB->I2S converters from DDAC (PCM2707 based), then to PC: both Opus are playing music now together with Foobar. Tomorrow I'll compare the Opus with my Wolfson 8740 evaluation board.

Interesting is that the two Opus can play together with Foobar (tried it in XP and Vista). The system detects both PCM2707 as "USB Audio Dac" and installs the drivers automatically. But you can't use two USB Audio Dac with Foobar directly.

First you must use ASIO4ALL asio driver. ASIO4ALL detects the two Dac and assigns two ASIO channels for each one for a total of four channels. When done, Foobar detects 4 independent outputs.

Bad news is that I'm not able to make work the Foobar DSP crossover plugin (http://xover.sourceforge.net/.)

Does it exist another DSP software or somebody can take a look to the Foobar plugin?


P.S.
The DDAC USB boards will go to my PC at work, so I'm still waiting for USB boards to be released by Twisted Pear to order together with a couple of Ballsie

 

[fierce_freak]

Is there any place I can get the schematic for the old receiver board? Thanks

 

[BrianDonegan]

http://www.twistedpearaudio.com/images/opus/receiver_sch.pdf

 

[DarrenWadsworth]

Wire gauge between IEC socket and Transformer?

I am planning on using a terminal block to connect the 2 transformers for my diy cd-player to the single IEC input socket. What gauge wire should I use between the 110v power input socket and the terminal strip?

Thank you
Darren

 

[Russ White]

Re: Wire gauge between IEC socket and Transformer?

I am planning on using a terminal block to connect the 2 transformers for my diy cd-player to the single IEC input socket. What gauge wire should I use between the 110v power input socket and the terminal strip?

Thank you
Darren

18-20ga should be just fine. At the currents the CDP or DAC will see anything more is overkill.

 

[Dougie085]

Is the Opus no longer available as a kit? Your site only shows assembled parts. I was suggesting it to a friend as a little first project but then I noticed no mention of a kit. Kind of sucks....

 

[BrianDonegan]

We no longer offer it as a kit. The reason is that we were pre-mounting the SMD parts (TSOP, very very small), but could not test them unless the rest of the board was built up.

The consensus from feedback (which we were surprised by) was that people preferred pre-assembled modules.

The new boards will be almost all surface mount parts, which would not make a very good first project.

FWIW: The power supplies will still be kits, and good for beginner builders.