Why no sound from iPad Air->Topping E30->Denon AVC-X4700h->Marantz MM7025?

[Brambo67]

Dear ASR forum members, I could do with some of your knowledge. I run a setup at home which is build around a Denon AVC-X4700h receiver. The speaker setup is 7.1.4. A Marantz MM7025 is driving the large front speakers. Everything works fine but I wanted to be able to listen to lossless sound via Apple Music. So I bought a Topping E30 which is connected via RCA to the analog CD input on the Denon. My iPad Air with USB-C is connected to the Topping via a USB-C - USB-B cable to the Topping. This is how it is (not) running:

1. Apple Music om iPad, Topping shows bitrate on display but no sound, Denon on CD as source and in ‘Direct’ or ‘Stereo’ mode; NO SOUND VIA SPEAKERS
2. Same but laptop with YouTube Music as source; NO SOUND,Topping shows bitrate however
3. Laptop with YouTube Music as source, Topping in Pre-Amp mode, Marantz MM7025 direct connected via RCA to Topping, PERFECT SOUND
4. Same but with iPad as Source; NO SOUND

Initially I thought there was now output but I proofed myself wrong with the above tests. Also multimeter proofed ’juice’ on the RCA cables. Which makes sense otherwise the #3 setup wouldn’t have worked.

So who can tell me what I’m missing or doing wrong.

 

[RickSanchez]

Have you tried this test?

1. (remove the Topping E30 from the signal chain)
2. Apple Music on iPad >> Denon X4700H (via Airplay2) >> Marantz MM7025

Just trying to narrow down the source of the problem.

 

[Zek]

iPad Air with USB-C is connected to the Topping via a USB-C - USB-B cable to the Topping.

4. Same but with iPad as Source; NO SOUND

Your USB-C to USB-B cable may not be suitable.

 

[Brambo67]

Ahum...... I have to admit I was the weak link... Turned out I hadn't assigned my CD-input to an analog output. Therefor no signal passed trough. Now it does flawlessly.