Russ,
If I were to wire up I2S and DSD with no switch to the DAC and soldered some leads to remote mount a switch for the dips on the module, would it work?
Or one better ... Could you not use an OTTO for the I2S and DSD data lines and have the relay switch with the front panel mounted dipswitch replacement?
If I were to wire up I2S and DSD with no switch to the DAC and soldered some leads to remote mount a switch for the dips on the module, would it work?
Or one better ... Could you not use an OTTO for the I2S and DSD data lines and have the relay switch with the front panel mounted dipswitch replacement?
khundude said:
1) Not if there is a signal on both at the same time. or if something tries to pull a line low while not in use. In short, I don't know, but I would tend to want to switch them if I used them both. I would not try it.
2)Using an OTTO to switch between DSD and PCM would work just fine.
in fact this will allow you to terminate the PCM/DSD lines differently. So you can terminate SDIF2 for the DSD at 75 ohms at one of the OTTO inputs. As for the the DIP switches, they are pretty much "set and forget" but if you wanted to run them to a panel you could.Cheers!
Russ
Russ White said:
1) Not if there is a signal on both at the same time. or if something tries to pull a line low while not in use. In short, I don't know, but I would tend to want to switch them if I used them both. I would not try it.
2)Using an OTTO to switch between DSD and PCM would work just fine.
Cheers!
Russ
Sounds fine to me... Once the dips are set I don't need to switch anymore between DSD and PCM? This is the part I am not sure of. Could you post the wiring scheme?
khundude said:
The schematic is on our site, and so too will be a manual here in a while.
On the Buffalo with the standard controller DSD and PCM are handled in the same mode. So no, you will not need to reset any DIPs to switch between the two. If you switch while the DAC is powered up there may be a small audio glitch as the DAC auto detects and switches modes, nothing too bad.
So if the little glitch bothers you then you can either mute the DAC (if you use your own controller and firmware) or only switch the inputs while the DAC is powered off. Cheers!
Russ
This sounds wonderful Russ! I had thought that the dips would have to be switched every time I moved from DSD to PCm and so on. I was thinking to myself that this was a serious oversight in design. Thanks for clearing that up for me.
Another question... Is it possible to get voltage output from the DAC single ended without using an outboard I/V to convert balanced to SE? I am not concerned about the drop in signal to noise as long as the dynamic range is not hurt too much. Should it not sound more natural with just a hint more noise, or does the IVY kick the hell out of the ESS in voltage out? If the sound is the same, what should be the input impedance of the preamp to use it in voltage out?
Another question... Is it possible to get voltage output from the DAC single ended without using an outboard I/V to convert balanced to SE? I am not concerned about the drop in signal to noise as long as the dynamic range is not hurt too much. Should it not sound more natural with just a hint more noise, or does the IVY kick the hell out of the ESS in voltage out? If the sound is the same, what should be the input impedance of the preamp to use it in voltage out?
khundude said:
The only time you have to tocuh the DIP switches (and a jumper) is if you change between SPDIF and PCM/DSD.
You can use it SE voltage out no problem, but DNR and THD will both suffer. How much so I am not sure.
What I can say with conviction is that the DAC does sounds far better (to me) with an active I/V stage as opposed to voltage out.
Cheers!
Russ
I think I have got it figured! Tell me if you think this would work Russ or anyone. I take the I2S wires from the Julia soundcard to the OTTO as well as the DSD lines from the player, and somehow wire the OTTO to switch when I turn on the SACD player. If that will not work, could I wire a switch for the OTTO to select DSD and maybe another OTTO that would switch on the SACD player. This way the signal would be sitched before the SACD player could fire up. Would this eliminate the noise? I would like to use a micro controller that would mute the DAC, hmmm, when do you think you will have the Uber Controller ready? I know you are busy, but have you made any progress on the Uber?
Uber is coming along well. It will be ordered with the next batch of boards but it still needs to be tested etc.
The little audio glitch comes from the DAC itself changing states and re-locking its DPLL. So there is no way to avoid it unless you mute the DACs one way or the other. I actually don't think you will find it worth worrying much about eliminating it.
There are lots of ways you could choose to switch the OTTO. You could trigger it when the SACD player comes on, that should work fine.
Here is a practical example:
On the Denon DVD-1920 mod I will be doing I will use both PCM and DSD. There is an LED that lights when the player is playing an SACD I will tap that line to trigger an OTTO. So when the LED is lit the OTTO is sending DSD to the buffalo, when it is not lit it is sending PCM. All of this fits nicesly in the DVD-1920 case when you remove the analog module (very easy).
Cheers!
Russ
The little audio glitch comes from the DAC itself changing states and re-locking its DPLL. So there is no way to avoid it unless you mute the DACs one way or the other. I actually don't think you will find it worth worrying much about eliminating it.
There are lots of ways you could choose to switch the OTTO. You could trigger it when the SACD player comes on, that should work fine.
Here is a practical example:
On the Denon DVD-1920 mod I will be doing I will use both PCM and DSD. There is an LED that lights when the player is playing an SACD I will tap that line to trigger an OTTO. So when the LED is lit the OTTO is sending DSD to the buffalo, when it is not lit it is sending PCM.
All of this fits nicesly in the DVD-1920 case when you remove the analog module (very easy).Cheers!
Russ
I2S from Juli@ caveat
I want to add a caveat to the Juli@ I2S outputs. I use this and I'm driving 15 foot lengths of RG-174U ( 50ohm ) coax, since my PC and DAC are a ways a part. I still have the Analog board connected. So what, right?
There is a lot of high frequency noise on the signals (0.4V riding on VDD and VSS signals). I have not spent much time trying to troubleshoot this.
My Audio Alchemy DTI Pro32 will not lock onto this I2S. I think the input is some TTL input buffer.
I have a Perpetual Technologies P-3A and it does lock onto 44.1k, 88.2k and 96k signals perfectly. However the P-3A uses a DS26C32AT receiver chip, according to Peter Madnick. This chip is an RS422 quad receiver with 200 mV input sensitivity.
I also want to try the Buffalo with the Juli@, but it may require cleaning up the I2S outputs. I was planning to try 1) remove the analog board 2) perhaps add an output buffer to drive the cables 3) perhaps switch to CAT5 cables instead of coax.
I want to add a caveat to the Juli@ I2S outputs. I use this and I'm driving 15 foot lengths of RG-174U ( 50ohm ) coax, since my PC and DAC are a ways a part. I still have the Analog board connected. So what, right?
There is a lot of high frequency noise on the signals (0.4V riding on VDD and VSS signals). I have not spent much time trying to troubleshoot this.
My Audio Alchemy DTI Pro32 will not lock onto this I2S. I think the input is some TTL input buffer.
I have a Perpetual Technologies P-3A and it does lock onto 44.1k, 88.2k and 96k signals perfectly. However the P-3A uses a DS26C32AT receiver chip, according to Peter Madnick. This chip is an RS422 quad receiver with 200 mV input sensitivity.
I also want to try the Buffalo with the Juli@, but it may require cleaning up the I2S outputs. I was planning to try 1) remove the analog board 2) perhaps add an output buffer to drive the cables 3) perhaps switch to CAT5 cables instead of coax.
15ft of I2S???
wackyterbacky,
if the Sabre is as tolerant of jitter as it seems to be, you might try s/pdif out. You may not be able to tell the difference. (again, assuming the sabre is as good as it claims at rejecting jitter) Might be a better way to go 15ft... (maybe a quality optical cable?)
as for I2S, if you expect it to travel that far, you will need a buffer. 15ft of even the best coax will prove to large of a load for most any chip not specifically designed for driving long transmission lines. (I'm surprised it works at all, the signal at the receiver must look pretty bad ;-) some termination, or a 75ohm coax could even help, hard to know what the output impedance of the I2S driver is. (probably not a perfect 50/60ohm)
-CK
wackyterbacky,
if the Sabre is as tolerant of jitter as it seems to be, you might try s/pdif out. You may not be able to tell the difference. (again, assuming the sabre is as good as it claims at rejecting jitter) Might be a better way to go 15ft... (maybe a quality optical cable?)
as for I2S, if you expect it to travel that far, you will need a buffer. 15ft of even the best coax will prove to large of a load for most any chip not specifically designed for driving long transmission lines. (I'm surprised it works at all, the signal at the receiver must look pretty bad ;-) some termination, or a 75ohm coax could even help, hard to know what the output impedance of the I2S driver is. (probably not a perfect 50/60ohm)
-CK
Russ White said:On the Denon DVD-1920 mod I will be doing I will use both PCM and DSD. There is an LED that lights when the player is playing an SACD I will tap that line to trigger an OTTO. So when the LED is lit the OTTO is sending DSD to the buffalo, when it is not lit it is sending PCM.
Thats a great idea, I will try that as well. What kind of cable will you be running from the player to the buffalo? Im thinking that a shielded CAT6 cable would do the trick, but Im not sure how long I could run it. Might only need 20cm or so between the boxes.
Russ White said:
I will probably just use small coax or CAT5. I may even try it with bare wire at first. The wire run should be pretty short.
While I know it was not great, I was amazed how well the DSD did even with about 3ft of ugly wire.
Cheers!
Russ
This is so cool, I cant wait to try it. I have to get my hands on a Denon 1920 first and of course the Buffalo DAC
Thanks Russ for all the great info and the good work.
I've been following this thread since early on, and am very excited to try out the buffalo. I'm interested to see how well it handles jitter (no I2S here - just spdif ;-) and how well it compares overall to my Lavry DA10.
In the process I've discovered a few other items of use on the twisted pear site (darwin, OTTO, & the JT attenuator) I'm saving my pennies and making a shopping list.
Any solid plans yet on when the JT & the buffalo will be back in stock?
Thanks!
-CK
I've been following this thread since early on, and am very excited to try out the buffalo. I'm interested to see how well it handles jitter (no I2S here - just spdif ;-) and how well it compares overall to my Lavry DA10.
In the process I've discovered a few other items of use on the twisted pear site (darwin, OTTO, & the JT attenuator) I'm saving my pennies and making a shopping list.
Any solid plans yet on when the JT & the buffalo will be back in stock?
Thanks!
-CK
Re: 15ft of I2S???
wackyterbacky et. al.,
Please keep us apprised of your progress in hot-rodding the ESI Juli@!
I'll be watching with interest because I have an older ESI board to which I HOPE I can add some 'Buffalo sauce'. It is the external "Wami-Rack 192X" that uses the AKM 4355. [The board was an e-bay special - I've kept it because I like the software even though the DAC isn't pristine.] Considering a mod, I would need six balanced channels (with I/V) so it's not a good project for experimentation. 
Moreover, I have been unable to confirm with the manufacturer's tech support that the DAC is being fed I2S data. ... so if anybody happens to know...
I would add that the stock interface cable for this older rack-mount DAC was 15 feet. When I replaced that cable with one that was 2.5 feet the sound improvement was not subtle.
Good luck and again, your results & insights will be appreciated.
Frank in Mpls.
wackyterbacky et. al.,
wackyterbacky said:
Please keep us apprised of your progress in hot-rodding the ESI Juli@!
I'll be watching with interest because I have an older ESI board to which I HOPE I can add some 'Buffalo sauce'.
It is the external "Wami-Rack 192X" that uses the AKM 4355. [The board was an e-bay special - I've kept it because I like the software even though the DAC isn't pristine.] Considering a mod, I would need six balanced channels (with I/V) so it's not a good project for experimentation. Moreover, I have been unable to confirm with the manufacturer's tech support that the DAC is being fed I2S data. ... so if anybody happens to know... I would add that the stock interface cable for this older rack-mount DAC was 15 feet. When I replaced that cable with one that was 2.5 feet the sound improvement was not subtle.
Good luck and again, your results & insights will be appreciated.
Frank in Mpls.
Russ, that is a great idea with the LED to switch the OTTO! Do you have any suggestions on other pure DSD players to mod, the cheaper the better. I often see the likes of old Pioneer DV-563A's and other Denons on Ebay or locally. After finding out that Oppo converts the DSD to PCM first, I began to look for another option. I don't need a DVD player either, it can be a Sony SACD player or such. Suggestions anyone?
One or two more things about transformers for the power supplies. Are the ones you sell able to be wired for 230v operation as I will be back in Asia in four months? Same with the Denon player, will it be easy to convert to 230v or do I buy one with 230v?
One or two more things about transformers for the power supplies. Are the ones you sell able to be wired for 230v operation as I will be back in Asia in four months? Same with the Denon player, will it be easy to convert to 230v or do I buy one with 230v?
