Sound level difference between XLR and RCA

[orbano]

Hi all,

I made a change in my config and there is a result I didn’t expect and which I don’t understand. Maybe you have some ideas…

Previous config was a Wiim Ultra feeding a Musical Fidelity pre-amp (m6s) via RCA, then feeding a Boxem Audio Arthur via XLR for a pair of speakers in my living room and in parallel feeding a Atoll AM100 via RCA for a pair of speakers in my kitchen. The living room and the kitchen are located at both sides of one large room.

I wanted to simplify a bit the config and use the Wiim Ultra as pre-amp and get rid of the Musical Fidelity. But as I need to feed two amp, I bought a Topping E70 which has both XLR and RCA output. So now its Wiim Ultra -> Topping E70 -> Boxem and Atoll in //.

But the level of sound in not the same anymore… Sound in the kitchen part of the room is much lower than before, in regards to the living room side. I can barely hear the sound coming out of the speakers in the kitchen, I mainly hear the sound of the speakers from the living room side. While before it was well balanced.

And I don’t understand why I have this difference now. Based on the spec of the Topping and the Musical Fidelity, there is the same ratio of output (XLR is supposed to output two time more V than RCA), even if numbers are not the same. I was expecting to keep the same balance.

Any idea of why I have this difference? I didn’t try to measure things with a voltmeter, not sure I have the right tool to do it. Possibly the real ratio between XLR and RCA in the Musical Fidelity or the Topping is not 2...

And next question is what can I do? I could change the config of the Boxem, to set the gain setting to low (currently it’s middle, as it’s the recommended option for 4 V). Or change the Atoll for a more powerful amp. Or get back to the previous config with the Musical Fidelity…

Thanks for comments.

 

[staticV3]

The M6s has 12.7dB gain, so at full volume it can amplify the WiiM's 2.0Vrms RCA out to 8.6Vrms.

In contrast, the E70 will output 5.0Vrms via XLR and 2.5Vrms via RCA.

I'd highly recommend that you use a basic $10 multimeter and the 60Hz test tone attached below to measure the output voltage of your E70 and to confirm that you're getting the voltages that you're supposed to.

If you have room correction enabled on the WiiM, please disable it for this test.

Here's how to probe RCA:


XLR output voltage is measured between Pin 2&3:

 

[orbano]

Hi @staticV3, thx for the explanaitions. I tried with my basic multimeter, but didn't succeed having a stable measure. I'll try again later.

 

[orbano]

So... I had to buy a new multimeter, more precise. Result, with wiim at max volume, 1.43 V for RCA and 2.86 for XLR. Ratio is as expected.
Now need to measure the musical fidelity... but first plug it again...

 

[staticV3]

Result, with wiim at max volume, 1.43 V for RCA and 2.86 for XLR.

About 5dB short of what you should see. In other words, 70% of the theoretical maximum volume.

Is the E70 set to 5Vrms and Max volume? Did you turn off the WiiM's EQ before measuring?

 

[orbano]

I've measured the output of Musical Fidelity and same voltage for XLR and RCA.
I have the answer to my initial question: with E70 the RCA is divided by two, which explains the difference.

Is the E70 set to 5Vrms and Max volume? Did you turn off the WiiM's EQ before measuring?

E70 is in DAC mode, but with 4V as default output. No EQ at Wiim.