Unity-gain "amp" for high-efficiency speakers

Thanks all. I built an amp with OPA548 at unity (i.e., connecting output to inverting input), and although the sound was good, it was not loud enough for classical solo music (i.e., no loudness war there). My room is about 18' by 26' and 10', and the speakers a bout 15' away from me. I think I may need 2x to 5x voltage gain.
 
Thanks all. I built an amp with OPA548 at unity (i.e., connecting output to inverting input), and although the sound was good, it was not loud enough for classical solo music (i.e., no loudness war there). My room is about 18' by 26' and 10', and the speakers a bout 15' away from me. I think I may need 2x to 5x voltage gain.

Since you are looking for some gain, and given all the Class A suggestions by other folks, you should look at Diegomj’a DLH amp. Really a superb sounding amp. I actually built it based on his schematic before he even tested it. It has about 12w and a superb harmonic distortion profile that’s adjustable for relative H2/H3.

Really simple and few parts too.

There are Gerbers and iron on transfer PDFs available.

Here was my home etched version using a Sharpie for acid resist:
633542d1504516574-dlh-amplifier-trilogy-plh-jlh-amps-dlh-build-02-jpg


The Sharpie etch worked so well I had to do a proper iron on transfer etch:
634478d1504940825-dlh-amplifier-trilogy-plh-jlh-amps-dlh-pcb-xrk-01-jpg


But look at the measurement at 2.83v:
633970d1504677045-dlh-amplifier-trilogy-plh-jlh-amps-dlh-0-cw-baseline-fft-png