My Ultra tests
- Thread starter onlyoneme
- Start date
The PL-8C and CN-1800S are great products.
Continuation of the main post - headphones output.
Dynamic Range, 118.7 dB:
IMD SMPTE:
Rather poor.
NID multitone:
Highly saturated.
THD / sinad vs digital level:
IMD SMPTE vs level:
THD / sinad vs frequency for 0 dBFS sine signal, without the LPF:
Dynamic Range, 118.7 dB:
IMD SMPTE:
Rather poor.
NID multitone:
Highly saturated.
THD / sinad vs digital level:
IMD SMPTE vs level:
THD / sinad vs frequency for 0 dBFS sine signal, without the LPF:
Last edited:
Subwoofer output
Idle noise first:
Seems to be less affected by the PSU noise spikes. Maybe it's because of another DAC being used? This time I will not use the LPF.
Sine 100 Hz full scale, crossover at 200 Hz, one channel driven:
and both, L and R channels:
Output level was 1.89 Vrms when both channels driven.
Crossover slope, 24 db/oct:
Idle noise first:
Seems to be less affected by the PSU noise spikes. Maybe it's because of another DAC being used? This time I will not use the LPF.
Sine 100 Hz full scale, crossover at 200 Hz, one channel driven:
and both, L and R channels:
Output level was 1.89 Vrms when both channels driven.
Crossover slope, 24 db/oct:
Last edited:
To be fair - better result than most integrated amplifier using a resistor i series directly from the power amp ?
My wild guess is that WiiM ultras headphone chip is maybe directly coupled to the regulated smps for the whole unit, and dont use any extra regulator before the headphone amp chip ?
Can you measure the output impedance from both the earphone amplifier and the analog output from the WiiM ultra ?
This is very important to know for preamp use through rca and use of the headphone amplifier .
Last edited:
This headphone amplifier chip has a PSRR of only -75 dB. Very good performance otherwise .
This means one should have a dedicated regulator after the main SMPS for this tpa 6120 chip .
Maybe this is already done.
Last edited:
40 ohm if the formula here
Measuring input impedance and calculating output impedance calculation calculate audio amplifier op-amp how to measure impedance voltage gain total loudspeaker speaker microphone resistance resistor bridging matching test load loudspeaker source resi
Calculate input impedance and measure output impedance calculation total audio amplifierr op-amp how to measure impedance voltage gain total loudspeaker speaker microphone resistance resistor bridging matching test load source resistance - Eberhard Sengpiel sengpielaudio
Thats a very high impedance for a headphone amplifier , makes it less good to drive low impedance 32 Ohm headphones.40 ohm if the formula here
is correct.Measuring input impedance and calculating output impedance calculation calculate audio amplifier op-amp how to measure impedance voltage gain total loudspeaker speaker microphone resistance resistor bridging matching test load loudspeaker source resi
Calculate input impedance and measure output impedance calculation total audio amplifierr op-amp how to measure impedance voltage gain total loudspeaker speaker microphone resistance resistor bridging matching test load source resistance - Eberhard Sengpiel sengpielaudiosengpielaudio.com
What is the output impedance of the analog rca out ? Is it 100 Ohm or higher ?
I will tell you tomorrow.
Im curious - Have you measured the impedance from rca out ?
I remember when brantome call me that. To me @onlyoneme and @Brantome are truly legend of this forum. Thanks you guys!Be more patient young Padawan
I thought you with the golden ears were C-3PO.
Ok Obi-wanBe more patient young Padawan
11 ohm.
