There's a "near mint" Audio Research Sp-9 Mk III (heavily upgraded) for sale on this site for about $1650.00
https://www.audiogon.com/listings/lis9bijd-audio-research-sp-9-mkiii-near-mint-preamp-tube
https://www.audiogon.com/listings/lis9bijd-audio-research-sp-9-mkiii-near-mint-preamp-tube