Scope analysis of Dudu 7, Nakamichi 5510, Onkyo X-QD1300 and whatever else comes my way

[alitayyab]

First off kudos to @devils_smile for his assistance many many times . He introduced me to what's good and what's available locally. I am pretty much tone deaf, so without his assistance I would be nowhere.

Also thanks to sound valley, Rawalpindi. I have bought tons of stuff on @devils_smile recommendation. I got the Onkyo from him, as well tons of sound deadening stuff among other things

The premise.

I got a relatively economical scope, hantek 2000 series.

I some videos, read up on how to use scope to measure pre out signals, set gains and clipping among other things. I have had it for a day so bear with me while I learn it's intricacies. If I am doing something wrong please do let me know

Anyways, starting off with pre out signals, here are universal settings I am using/ will use.

1.1 khz 0db tone. Link: https://www.mediacollege.com/audio/tone/download/

1. All dsp effects off, eq flat

2. volume setting set to max. Some android units have a speaker power setting like Onkyo and dudu. Those were set to max

3. Volume raised till either the signal clips or max volume reached

4. Videos will be jittery; Fasting and tired. Also doing this for fun not science!

1. Dudu 7

Vpeak at full volume, full power < 4V. No visible clipping on Pre-outs
Vmax = 4.08; Vpp = 8.08; Vrms = 2.85
Vmax approaches 4 volts at really high volumes (31 on the volume setting with full speaker power at 490). The fan kicks in at about 30 volume setting). There is a sudden spike from ~2.8 to 3.5 to 4 volts at volumes > 25

2. Nakamichi 5510
Coming up

3. Onkyo xqd 1300
Coming up later.

[ali199]

Interesting post, for DUDU7 I did measure preout voltage with DMM and it turns out 4.3v rms at max volume. Oscilloscope is also ordered, will see how it pans out.

Planning to buy a branded unit but not easy to ditch tons of features this android unit provides.

[pwuser162411347231]

Honestly Android Auto and android os as a whole is garbage for audio. Android auto has a habit of cutting off above 17khz and android os has src resampling which can be bypassed by UAPP but only if you have Tidal or Quboz if you are using any other streaming service like Apple Music you are cooked with no option on Android. Waiting for the day big brands give optical or coax out on their head units. Carplay and iOS is far better they offer bit perfect audio.

[pwuser162411347231]

Quick tip changing android auto codec to prefer PCM clears up audio a bit

[ali199]

Bid brands offer optical out at 5x the price of a quality android unit. When feeding a DSP using optical out, the difference should be negligible in branded vs some quality units.

[pwuser162411347231]

Which big brand is offering optical out? As far as I know only Alpine is offering optical out and that too isn't a standard headunit more of player.

[ali199]

Some Stinger units as well but those are not good units either. Only option at this moment is Androids with optical and coax out. I will test that when I get a DSP for my system.

[pwuser162411347231]

Stinger is garbage with the same SRC issue so optical is of no use. The only option is to get a DAP or if you using Apple and Helix dsp get a HEC USB card and connect the iphone to the dsp via usb. For Android an external dac.