I have a 20+ year old Audiolab 8000A amp linked to Monitor audio Silver RX1 and Marantz CD6004, I think its time for a new Amp. Would I be better off with a marantz PM6004 as a match for the CD player or possibly just upgrading the 8000A as I have seen variuos upgrades advertised on a certain trading site. Or I am open to other suggestions.