GUSTARD DAC-R26 Balanced Decoder R2R+1Bit Dual Native Decoding Music Bridge

[Jake2]

Just got my LHY OCK-2 connected to the U18. I notice the R26 now lets me select an external clock without erroring. Does this mean both the R26 and U18 are using the external clock connected to the U18?

And does anything know if I should be using the sine wave, or square wave output on the OCK-2?

Thanks


Edit: The R26 does seem to throw the "EXT ERR" most of the times when trying to set to use the external of the U18

Re sine vs square try both and see which you prefer. The R26 can take both. I've found sine works best with both the OCK-1 and OCK-2 with the R26. One reason for this may be that sine is less sensitive to impedance mismatches, even small ones, that can arise at multiple points in the signal chain from the clock oscillator through the two sets of BNC plugs and sockets to the clock receiver on the DAC board. Whereas for sine quality shielding is more important. Another is that the quality of the sine-square wave convertor included in a clock can vary, though plots I've seen on the OCK-2's square (and sine) plots look pretty clean.

In terms of the clock synchronisation errors on the R26 not exactly sure what you're describing here, but FWIW:

• Assumption is you have EXT Clock set to ON on the R26
• If you've got errors from just connecting the OCK-2 to the R26 10mhz BNC input then that is unusual, may be related to the quality or type of the BNC plug/socket connection or stress on the cable. I found with heavy LMR400 cables mean I sometimes got an error and had to slightly jiggle the cable to get it to connect properly, and the ERR message go away. I can't think why connecting the OCK-2 to both the R26 and U18 would reduce the incidence of such synchronisation errors.
• The U18's 'WCLK' BNC output is a Wordclock output (i.e. timing info directly related to the stream of digital audio) not a masterclock (10mhz timing pulse only) output. You can't connect the WCLK to the R26's masterclock input - if this is what you've tried I'd expect to get an error on the R26.
• If you're using I2S, s/pdif or AES to connect the U18 to the R26 then the U18 will pass the wordclock to the R26 via that connection which the R26 will use (i.e. not reclock) and, depending on how you read Gustard's email clarification they provided to @mmwwmm (see below), seems to mean that the R26 only gets an improvement from an external clock only when oversampling is turned ON i.e. PCM NOS & DSD Direct OFF. That said I've found clear audible benefits from an external clock connected to the R26 (toggling EXT Clock ON/OFF) when it is fed I2S from the U18 when the R26 is set to DSD Direct and/or PCM NOS ON. Probably TMI but hope some of this helps...

This is an answer from Gustard regarding the use of a 10Mhz external clock with the R26 and when its clock signal is used to reference the internal K2 synthesizer and when is not used.


When playing PCM

1. PCM NOS: OFF
The improvement provided by the external clock applies to all R26 inputs.

2. PCM NOS: On
The improvement provided by external clock applies to USB and LAN inputs, IIS AES coaxial optical Bluetooth does not apply.

When playing DSD

1.DSD DIRECT: OFF
The improvement provided by the external clock applies to all R26 inputs.

2.DSD DIRECT: ON
The improvements provided by the external clock apply to USB and LAN inputs, IIS AES coaxial optical Bluetooth does not apply.

 

[Aeonyx]

Re sine vs square try both and see which you prefer. The R26 can take both. I've found sine works best with both the OCK-1 and OCK-2 with the R26. One reason for this may be that sine is less sensitive to impedance mismatches, even small ones, that can arise at multiple points in the signal chain from the clock oscillator through the two sets of BNC plugs and sockets to the clock receiver on the DAC board. Whereas for sine quality shielding is more important. Another is that the quality of the sine-square wave convertor included in a clock can vary, though plots I've seen on the OCK-2's square (and sine) plots look pretty clean.

In terms of the clock synchronisation errors on the R26 not exactly sure what you're describing here, but FWIW:

• Assumption is you have EXT Clock set to ON on the R26
• If you've got errors from just connecting the OCK-2 to the R26 10mhz BNC input then that is unusual, may be related to the quality or type of the BNC plug/socket connection or stress on the cable. I found with heavy LMR400 cables mean I sometimes got an error and had to slightly jiggle the cable to get it to connect properly, and the ERR message go away. I can't think why connecting the OCK-2 to both the R26 and U18 would reduce the incidence of such synchronisation errors.
• The U18's 'WCLK' BNC output is a Wordclock output (i.e. timing info directly related to the stream of digital audio) not a masterclock (10mhz timing pulse only) output. You can't connect the WCLK to the R26's masterclock input - if this is what you've tried I'd expect to get an error on the R26.
• If you're using I2S, s/pdif or AES to connect the U18 to the R26 then the U18 will pass the wordclock to the R26 via that connection which the R26 will use (i.e. not reclock) and, depending on how you read Gustard's email clarification they provided to @mmwwmm (see below), seems to mean that the R26 only gets an improvement from an external clock only when oversampling is turned ON i.e. PCM NOS & DSD Direct OFF. That said I've found clear audible benefits from an external clock connected to the R26 (toggling EXT Clock ON/OFF) when it is fed I2S from the U18 when the R26 is set to DSD Direct and/or PCM NOS ON. Probably TMI but hope some of this helps...

Thanks for the info!

I have the BNC cable connected to the sine wave output on the OCK-2, and to the WCLK input on the U18. When I try to enable the external clock setting on the R26, it throws an error. I'm guessing since it's connected to the U18 already via I2S, the R26 is getting the benefits of the clock from there without having to change any settings?

 

[Jake2]

Thanks for the info!

I have the BNC cable connected to the sine wave output on the OCK-2, and to the WCLK input on the U18. When I try to enable the external clock setting on the R26, it throws an error. I'm guessing since it's connected to the U18 already via I2S, the R26 is getting the benefits of the clock from there without having to change any settings?

Please confirm you've connected the OCK-2 to the 10mhz input on the U18, not the U18 WCLK BNC which is output only.

And the answer to your question is yes, once the U18 is synchronised to an external clock it will use that to generate the word clock signal it passes via i2S to the R26, nothing more you need to do.

 

[DivinesGaming]

Ehem...

If anyone's selling a Black R26/U18 - Send me a PM.

Carry on!

 

[Aeonyx]

Please confirm you've connected the OCK-2 to the 10mhz input on the U18, not the U18 WCLK BNC which is output only.

And the answer to your question is yes, once the U18 is synchronised to an external clock it will use that to generate the word clock signal it passes via i2S to the R26, nothing more you need to do.

Yep, just checked. 10M CLK connected. Really appreciate your help here!

So I don't need to enable external clock on the R26 since I'm connected via I2S?

I also only have a $50 makeshift eBay special connecting it currently lol. I'm sure that's not ideal. I have a Gustard C2 arriving tomorrow, pretty excited to try that.

Edit: One final question. So since R26 won't use the external clock when connected via I2S or USB with NOS on, does it even matter since it's technically the U18 using the clock? I wish Gustard would've been a bit more clear here lol

 

[Jake2]

Yep, just checked. 10M CLK connected. Really appreciate your help here!

So I don't need to enable external clock on the R26 since I'm connected via I2S?

I also only have a $50 makeshift eBay special connecting it currently lol. I'm sure that's not ideal. I have a Gustard C2 arriving tomorrow, pretty excited to try that.

Edit: One final question. So since R26 won't use the external clock when connected via I2S or USB with NOS on, does it even matter since it's technically the U18 using the clock? I wish Gustard would've been a bit more clear here lol

You don't need to do anything more to use the word clock from the U18, but as I said, despite Gustard's emailed guidance I and others find an audible improvement of also having an external clock connected to the R26 and selected via EXT Clock On even on I2S with PCM NOS or DSD Direct on. I would recommend you do this too to maximize the sound.

 

[Aeonyx]

You don't need to do anything more to use the word clock from the U18, but as I said, despite Gustard's emailed guidance I and others find an audible improvement of also having an external clock connected to the R26 and selected via EXT Clock On even on I2S with PCM NOS or DSD Direct on. I would recommend you do this too to maximize the sound.

Would it be fine to connect the same OCK-2 to both, or should I get a second clock?

 

[camrector]

Would it be fine to connect the same OCK-2 to both, or should I get a second clock?

OCK2 is the master clock for up to 3 devices.
Connect the OCK2 to both the R26 and U18 Sine or Square.
Select external clock on the R26

 

[Jake2]

Would it be fine to connect the same OCK-2 to both, or should I get a second clock?

As per @camrector ’s advice above. Definitely preferable to use a single master clock like the OCK-2 to ‘slave’ multiple components where possible, will ensure they’re all beating to the same drum. Particularly important when using a synchronous source like I2S, arguably less so where an asynchronous source like Ethernet is used.

 

[camrector]

FYI
Seems like the Denafrips crowd is losing their minds over how to do their new firmware upgrades lol.
I will say at least we have a screen to look at for confirmation. They just have a series of flashing lights.

 

[m-i-c-k-e-y]

... a series of flashing lights.

Morse Code...

 

[camrector]

Morse Code...

• • • — — — • • •

 

[welldonehd]

For my case, I have connected both U18 and R26 to OCK2, which makes the SQ better than using only one connection of U18 to OCK2. It is audible!

 

[Jake2]

For my case, I have connected both U18 and R26 to OCK2, which makes the SQ better than using only one connection of U18 to OCK2. It is audible!

Cool! With PCM NOS / DSD Direct ON?

 

[welldonehd]

Cool! With PCM NOS / DSD Direct ON?

Yes, that's right. Cuz i've been using Gustard P26 as preamp, without turning on PCM NOS/DSD Direct, I cannot maximize the volume out to P26.