Mu-so phono stage AT-LP5x

Hi all. I connected my AT-LP5x turntable (with built-in pre-amp) to my mu-so 2nd gen via RCA cables to 3.5mm jack. The sound is … ok. Lacks gain and is generally underwhelming. I got a Pro-ject phono box E and connected it to the turntable via rca, and to the mu-so via toslink optical cable. But it buzzed terribly! I added a grounding cable between the pro-ject box and the turntable, but it made zero difference -still a persistent low buzz.

Any advice on a better pre-amp solution to boost gain without buzz?

In the input settings of the app you can indicate, for analogue input, 3 input level options. Default is 2V IIRC, maybe try to set to 1V and see if with your first option that sounds better?

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Odd that you would get a buzz with an optical connection. May be a ground issue that needs a ground connection to the muso. Have you tried it with an analog connection to the muso?

That was a great tip, @Igro. The setting is not quite how you described it (see attached screenshot), but the result is the same: gain boost!

Agree that the buzz with optical cable is weird. I went straight analog first — rca fromTT to 3.5mm jack to Mu-So — and there was no buzz, just low volume.

How would I ground the Mu-So? There isn’t a grounding point on it.

The Mu-So floats the earth. Getting a buzz from using the optical input makes no sense to me unless it’s an earth issue within the AT-LP5x that’s then being converted to digital along with the music signal.

Did you switch of the internal phono amp before connecting the PBox?

Yes, something to do with the AT and the Project grounding.