I’m using one. It’s a Pro-ject phono box e, probably one of the most common pre amps out there.It's a standard RCA input, probably somewhere from 800mV to 2V. You can get a phono stage to connect a turntable to it
Well, the input sensitivity is a design choice, I guess that in this case the WiiM Amp has a higher one and this leads to a lower max volume. I think it would be nice to have the official information, it is an important value that determines the way to match this amp with sources.Yes musig, same here.
It’s a shame we can’t get high volume from a phono pre amp that has a standard 500mV output through the line input. Does this mean the sensitivity of the line input is too low though?
If it is the "same box only for MC" then ... well ... it's not the same box, right?... it seems like the same box only for MC carts, so it should be ok.
First of all thank you for this investigation, it gives us precious information that can explain effects that we notice while using the WiiM Amp. Besides, I think that this is a specification that WiiM should provide because it makes a lot of difference knowing it in advance. In a use case like @Petevid 's one I would have made a different choice because phono preamps often have much lower output voltage.According to @WiiM Support the Amp uses the Texas Instruments PC1861 ADC. According to its spec sheet this ADC needs 2.1 V input voltage for digital full scale single-ended (or 4,2 V for a balanced input). The RCA input is single-ended by nature and I wouldn't expect WiiM to have added an additional gain stage before the ADC (maybe a buffer or just some protection circuitry).
If these assumptions are correct, then the input voltage would in fact be 2.1 V. Anything lower than that could not drive the WiiM Amp to full power.
I would further assume that some digital gain could be added and be made adjustable through the WiiM Home App. This would reduce the SNR available from the ADC, but it might still be worth it for people trying to match a typical phono stage with the amp, given that LP records are an inherently much more noisy source anyway.