The Best DAC is no DAC

[Markw4]

No. Maybe normal to have 44kHz at LRCK for PCM.

 

[merlin el mago]

It’s with nothing connected to Amanero

 

[Markw4]

If no USB cable and no power connected, then there shouldn't be anything coming out.

 

[merlin el mago]

Power connected for Amanero

 

[merlin el mago]

It’s possible channels swapped by firmware?

 

[Markw4]

Firmware should not swap channels that way, at least I haven't seen it before. Therefore I would suggest to check some other things.

How are you measuring? With what instrument? On what pins? What do you measure if you send the Amanero some PCM audio? What if you send DSD audio?

 

[merlin el mago]

I'm mesuring with DVM Brymen BM869s http://www.brymen.com/PD02BM860s_869s.html

Red probe to Amanero pin 4 BCLK & black probe to Amanero pin 14 GND, DVM set AC displaying VAC RMS & Hz.

Tomorrow I will measure sending PCM & DSD, thanks Mark.

 

[Markw4]

The Brymen DVM can only measure and display frequencies up to 200kHz. That's not high enough to measure BCLK.

 

[merlin el mago]

Is enough my old Hameg HM 412-5 bandwith 20MHz?

 

[merlin el mago]

With the Amanero not powered I injected with the SG a sinus wave of 44kHz to the 2nd order LPF set to aprox. 20KHz and DVM not measured the 44KHz.

With Amanero powered I also injected the 44KHz signal to the LPF and DVM measured 22KHz....

 

[Markw4]

Is enough my old Hameg HM 412-5 bandwith 20MHz?

Depends what sample rate the Amanero is putting out. BCLK might only be a few MHz, so your scope might work.

 

[merlin el mago]

Thanks Mark, I will measure and tell you.

 

[merlin el mago]

Only Amanero powered USB disconnected, scope set 2V/cm 20us

 

[merlin el mago]

Same scope settings 1KHz DSD64

 

[merlin el mago]

1KHz DSD64 scope set 2V/cm 2us

 

[merlin el mago]

Music PCM 16/44 scope 2V/cm 20us

 

[Markw4]

Looks like your scope probe is badly out of calibration. Is it set to x10?

Is the time scale 20us or .2s? The pic doesn't show the switch setting clearly.

Anyway, take the period of one full cycle and divide it into 1 (take 1/x). That should give the approximate frequency.

 

[merlin el mago]

Probe is x1 and well calibrated.

About the time scale it depends the pic, tell me wich one?

 

[Markw4]

Square wave looks better, thank you.

Sweep rate knob is out of focus. If you say its 20us/division, then let's use that number. So, maybe one cycle is about three and a half horizontal divisions. So that's about 70us for one cycle.

Taking 1/p where p is the time period for one cycle in units of seconds, gives somewhere roughly around 14kHz.

 

[merlin el mago]

Probe is x1 and well calibrated.

About the time scale it depends the pic, tell me wich one?

The pic it's the calibration so you see it's the probe calibrated.