Twisted Pear Audio Support
»
Product Support
»
Digital
»
Buffalo DAC
»
proper feeding of dual mono buffalo IIIse with spdif
Rank: Member
Groups: Member
Joined: 1/19/2013(UTC) Posts: 7  Location: Madison Wisconsin
|
Hi
Built a stereo buffalo IIIse and love it but having been bitten by the diy bug I couldn't resist going for the dual mono setup. My question is in regard to the proper way to supply the spdif signal via coax to the two DAC boards: I know that others have asked the same thing but I am still confused.
one piece of background that might be relevant: I have a waveIO board that I plan to run from the NVE IL715 isolator chip to the I2C inputs of the DAC(s).
I have read recommendations to (1) to connect the commercial level spdif signal coax to one board and run a wire from D1gnd to the second DAC D1/gnd ( from Leon's build guide 1.0.5 but may only apply for the buffalo II), (2) use a Y cable off of the SPDIF input jack and (3) daisy chain the spdif inputs of the two dacs together.
Problems: if option (1) is still valid, how do I connect both the waveIO and spdif to the I2C D1 input? This doesn't seem possible
With options (2) or (3) wouldn't the input impedance be affected (ie it would no longer be 75ohm)? I need to only run about 20cm of coax between the input jack and the DAC boards. Will the drop in impedance negatively affect the DAC SQ?
Is there a termination resistor on the spdif input? If so, would it make sense to remove the termination resistor on the spdif input from the first DAC in the daisy chain thus the impedance for the input signal path to both DACs would be still 75ohm as a result of the remaining termination resistor on the second DAC? Other options? What about a video signal splitter or another twisted pear input module?
What have others done to solve this for their dual mono setups? Your "input" would be greatly appreciated
sebastian
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/6/2012(UTC)
Posts: 305
Location: Plainfield, IL
Thanks: 11 times
Was thanked: 26 time(s) in 21 post(s)
|
Greetings neighbor to the north. We get up your way a time or two per year used music shopping. When I went dual mono with my BIII I felt it wasn't twice as good but the improvement was worth the investment.
I think when splitting coax you would terminate twice which does affect the impedance. I think splitting also halves current to each DAC board.
I wanted multiple inputs on my dual mono build with I2S/DSD input so I use a TP 4 channel SPDIF input board attached to a TP Sidecar. The signal is split at the Sidecar and feeds each DAC. I wonder if the TP Single S/PDIF (or AES-EBU) Level Converter Kit is the way to go and split that signal to each DAC?
I’m sure Russ, Brian or Leon will chime in here.
|
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/19/2013(UTC) Posts: 7 Location: Madison Wisconsin
|
Hi SCompRacer
I been following you build exploits for the last couple of months. I must say that your dual mono looks beautiful. I bet it sounds as good as it looks. Let me know when you are coming to Madison next and if you are interested in meeting to talk about music and buffalos.
I was initially planning on only running spdif and usb into the dual mono I am building but I included room for the input board and jacks for additional inputs in the chassis (being machined by the wonderful modu folks at the moment) in the event that I needed them in the future.
So, the combination of spdif-4 input board (or single spdif level converter) and sidecar works for a dual mono buffalo III . I haven't been able to figure out if it will work for a dual mono buffalo III se setup. Thoughts? (other than you should have gone with the buffalo III for starters)
Are there other TP accessory board configurations that would be better and potentially less expensive: For example the otto-II which if I am reading correctly will take both spdif and the waveIO I2S signals? Will it distribute them correctly to the two buffalo IIIse boards?
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/6/2012(UTC)
Posts: 305
Location: Plainfield, IL
Thanks: 11 times
Was thanked: 26 time(s) in 21 post(s)
|
Thank for the kind words. Without coding help from Corpius I would have been stuck with manual control. My bad, I kind of blanked out about you having the BIIIse. It is like having a built-in Sidecar and Single S/PDIF Level Converter per the manual. Not sure about the best way to accomplish what you want with dual se boards. The manual says you can use a 4 channel input board with dual se boards, on page 43. The OTTO II is a two to one switch so only one output. Not sure if you could connect OTTO's shared output to all the appropriate DAC inputs without a problem. I have a ribbon cable that connects the Sidecar to both DAC boards. It is pretty close to equal length. I didn't need the full width ribbon as I am powering it with a separate power supply.  Edited by user Thursday, May 9, 2013 3:54:53 AM(UTC)
| Reason: Not specified |
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/19/2013(UTC) Posts: 7 Location: Madison Wisconsin
|
thanks for pointing out that the manual indicates that the Spdif-4 input board can be connected to the Buffalo IIIse.
Russ and/or Brian.....Your thoughts on the best way to run both spdif coax signal and PCM output from a WaveIO into a dual mono Buffalo IIIse setup? Is it possible to use the Spdif-4 input board and Sidecar as is done for the buffalo III?
|
|
|
|
|
|
Rank: Administration
Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 3,979
Location: Nashville, TN
Thanks: 25 times
Was thanked: 89 time(s) in 83 post(s)
|
My first inclination would be to not use SPDIF directly. But to use a SPDIF receiver as an I2S source. We have a 4:1 SPDIF MUX which works very well at this. This way you could use an OTTO-II and switch between the two I2S sources (one of which is from SPDIF). Alternatively you could likely just wire the SPDIF inputs in parallel from a consumer source. The termination will be half impedance - but in practice that should not matter much to most sources. The SPDIF level will be somewhat lower, but not enough to effect the comparator. One other option would be to create a simple repeater using our single SPDIF level converter and a voltage divider. Something like 221R/221R ( preceded by an AC coupling cap - say 100nf ) would work fine. Then wire that to both SPDIF inputs (in parallel) as usual. Cheers! Russ Edited by user Thursday, May 9, 2013 2:06:40 PM(UTC)
| Reason: Not specified
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 5/23/2010(UTC)
Posts: 708
Location: Netherlands
Thanks: 2 times
Was thanked: 48 time(s) in 45 post(s)
|
Originally Posted by: sybednar  thanks for pointing out that the manual indicates that the Spdif-4 input board can be connected to the Buffalo IIIse.
Sorry, but that is an error in the documentation. The BIIISE does not have it's inputs exposed as the original BIII, and as such it can NOT handle the 4 inputs of the SPDIF-4 board. If you want 4 SPDIF inputs, use the Mux as Russ suggested along with an OTTO-II to switch between the I2S sources (Mux and WaveIO).
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/19/2013(UTC) Posts: 7 Location: Madison Wisconsin
|
Russ and Leon
Thanks for the suggestions and correction that the spdif-4 board is not compatible with the III se.
Last questions: powering the spdif-Mux and otto
according my quick reading of the manual/description of the two boards, the spdif-Mux needs 5-12VDc supplying at least 60mA whereas the otto requires 4-5.5V (current requirements?).
I have one dedicated placid HDs per buffalo DAC IIIse board in my dual mono setup (ie two placid HDs)
thoughts on running the spdif-Mux off of one placid Hd and the otto of of the other? Or would it be better to have a completely separate supply for each accessory board?
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/19/2013(UTC) Posts: 7 Location: Madison Wisconsin
|
Ooops....
forgot to ask the other last question:
Just to be sure, the output of the otto II is sufficient to be fed into my two buffalo III se DAC boards?
Thanks again for all your help
|
|
|
|
|
|
Rank: Administration
Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 2,868
Location: Massachusetts, USA
Thanks: 2 times
Was thanked: 141 time(s) in 134 post(s)
|
Originally Posted by: sybednar
Last questions: powering the spdif-Mux and otto
according my quick reading of the manual/description of the two boards, the spdif-Mux needs 5-12VDc supplying at least 60mA whereas the otto requires 4-5.5V (current requirements?).
I have one dedicated placid HDs per buffalo DAC IIIse board in my dual mono setup (ie two placid HDs)
thoughts on running the spdif-Mux off of one placid Hd and the otto of of the other? Or would it be better to have a completely separate supply for each accessory board?
You could easily power both modules from one of the Placid HDs, just bump up the output current a bit.
|
|
|
|
|
|
Rank: Administration
Groups: Administration, Customer
Joined: 10/24/2006(UTC)
Posts: 2,868
Location: Massachusetts, USA
Thanks: 2 times
Was thanked: 141 time(s) in 134 post(s)
|
Originally Posted by: sybednar
the output of the otto II is sufficient to be fed into my two buffalo III se DAC boards?
Yes. Use the terminal block and run separate lines to each DAC (do not daisy chain).
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/19/2013(UTC) Posts: 7 Location: Madison Wisconsin
|
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/6/2012(UTC)
Posts: 305
Location: Plainfield, IL
Thanks: 11 times
Was thanked: 26 time(s) in 21 post(s)
|
Kewl! You have some great input now.
What chassis did you get from HiFi 2000/modushop? Are you dealing with Andrea? |
|
|
|
|
|
|
Rank: Member
Groups: Member
Joined: 1/19/2013(UTC) Posts: 7 Location: Madison Wisconsin
|
I just keep going further and further down the "rabbit hole" with this build. Every upgrade leads to another.
Andrea and Gianaluca at modushop have been great. He machined a front panel for me last year for another project and did such a good job that I didn't hesitate (even though it isn't cheap) to have them make the panels for the DAC project. Beside, I couldn't find a US vendor that does post-machining oxidation
cheers
|
|
|
|
|
|
Twisted Pear Audio Support
»
Product Support
»
Digital
»
Buffalo DAC
»
proper feeding of dual mono buffalo IIIse with spdif
Forum Jump
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.
