Phono Stage Amp

I have the SLP 05 with two Primaluna Dialogue 7 monoblocks. I use speakers with powered bass, GoldenEar Triton Reference. No power problem. You could get more amps and biwire your speakers.

     From the OP:

"... with volume halfway up on the SLP-05 using an Audia Flight CD* player the volume is very high and no distortion."

     From the previously cited M1** review:

"I just want to add that, while the gain for the MM stage is 40 dB, the classic one, for the MC is below 60 dB. This will require a deep attention to the level of the cartridge output and, chiefly, to the input sensitivity of the other components of the audio chain, which has to be progressive, otherwise the risk is that the system will not perform correctly, also with very expensive components. This is a universal rule. Keep it always in mind when you assemble your hi-fi system."

                                   *2V max output           **300mV max output

@cinqcepages -

     Probably: the least expensive experiment, in order to narrow down your issue, would be to purchase/mount the cheapest MM cart available and see if it results in a satisfying SPL.

                ie:

https://www.turntablelab.com/collections/best-turntable-cartridges-by-price-ttl-levels

      Alternately: an SUT (easier to install/more expensive, probably), but: may increase noise/hum.

      Personally: I'd be looking for a phono stage, capable of outputting between 1 and 2V, with greater gain than 60dB in the MC stage. 

Would not call or consider a music hall 11.1 low end...it's not exactly cheap....

Could the issue be an ultrasonic peak of the Mc cartridge causing clipping at higher volumes? Think about cartridge loading. MC carts typically have increasing output as frequency increases, well into the ultrasonic range. Load resistors tamp this down. 

If your phono stage does not have a way of adding load, you can load your cart output at the turntable output with a little bit of gerryrigging.