Its a cheap consumer amp. But it's hard-wired in its place and it has integrated features that we use. Tuners etc.
Even if it would be cheap to buy a new amp, the job to replace the existing amp would be more expensive than its worth.
There are no input level options on the amp, everything is configured correctly. I think it's just a combination of a weak amp, insensitive speakers, and sensitive hearing.
The amp is working fine for us to play music normally, but it has trouble hitting 83dB so that Loudness can work correctly.
I don't think there is any way to add gain without clipping.
I think you misunderstand how Loudness works. This reference value is used to determine when Loudness is turned off. Loudness applied, using a variable amount based on the value of the volume slider. When the volume slider reaches the value you put into "reference", it stops applying Loudness compensation.
I think you misunderstand. The reference is fixed at 83dB in JRiver. You don't get to pick the reference, and that's the problem.
The "reference level" setting is telling JRiver what digital volume level plays 83dB out of your speakers.
Because the highest the "reference level" can be is 100, it means that the lowest volume your amp can be set to is 83dB.
JRiver internal volume is normally in the 15-30% range when everything is calibrated to 83dB.
If the reference level could be reduced from 83dB to something lower it would give me better volume control and more SNR.
I tried a few things that were suggested.
It seems that adding 20dB of gain with the PEQ doesn't affect loudness, only the volume control does.
This let me set the amp to 63dB at 100% volume, which eliminated the hiss.
But it means that the volume range in JRiver now has to be 0-10% instead of 15-30% which now has hiss from the DAC and volume jumps in big steps with every %.
So its just swapping the source of the SNR problems around instead of fixing things.
If I could set the "reference level" to 140, or change the reference from 83dB to 63dB it would get me 20dB of SNR and let me keep volume in a higher range.