Moderate Priced Integrated Amp

I live in a retirement community and a musician neighbor/friend has requested my assistance in putting together a high value, high performance stereo system to accommodate his tastes in classical (primarily) and jazz music. I am seeking advice since for the past 45 years I have lived in the high-end world. The centerpiece of this system would be a moderately priced solid-state integrated amplifier (or possibly a receiver) at a cost of under $1,000 (and preferably under $700). Purchasing used from a reliable seller is no problem. The listening room is small (as befits a retirement community) and the speakers we select will probably be in the 89db efficiency range. Neutrality, absence of coloration and tonal accuracy are definite requirements, as is reliability. My preliminary research has uncovered such brands as Outlaw Audio, many Cambridge products, Rega, Arcam and Music Hall among others. Further suggestions and bits of wisdom would be most welcome. Thank you for your time and patience.