Hello all!\n\nFirst of all, I have frequented this site for a while, just reading questions similar to mine and finding info I needed - it’s been a great help. Finally joined up!\n\nI’m currently running:\n\nSony Str-dh770\nPolk Rti-10 towers (bi-amp)\nB&W CC6 center\nPolk fx\/i3 surrounds\nPolk PSW505 (Amp just went out)\n\nI’m looking for advice on the next bang for buck. Currently shopping for a sub and receiver upgrade.There’s a Marantz SR5013 locally priced at $425 on Facebook - very interested. I’ve been without my sub for a month or so and the Rti10’s have pretty good base, so it’s been alright without the sub. The psw505 was maybe a bit much for my lvg rm. there is also a Martin Logan dynamo 700w thatI’m looking at picking up nearby. Also a good price - $300. I can probably talk her down, she’s asking for an offer... but I’m not sure if I’d rather have clearer better sound from the Marantz receiver (and better 4K \/ HDR capabilities, as well as airplay and other features), or if I should get the sub.\n\nAnything I buy at this point I’d like to keep for years to come. I wouldn’t mind swapping out my surrounds and center to match and have a full Martin Logan setup in the future. (Not sure if I’d replace my rti10’s ever, I absolutely love them.\n\nAny suggestions would be great! Thanks!