Best used amp for around 500

Ehart gives good advice. Is why I suggested a tube pre amp but that's my prejudice. He is right that the pre is important.

I remain,

I'll second David99 on the Dynaco ST-70.

Nothing touches it (even close) at the price and then some. Helps to have a little tube know-how but there are great dynaco web sites for help if you need it. A true entry level hi-fi unit. It will let you know how far the industry hasn't come in 40 years. Short on hype and gloss, long on sound. Get series I if you like warm and II if you like faster more SS sound.

Sincerely, I remain

Add on to above post. Sorry. You will need a pre with the Dynaco (I suggest Bottlehead Foreplay kit) and if you are fussy at all about music for pete sake go with a two channel!!!!!! Forget 5 channels on that budget if you like music.
I run an old ST70 with a PAS3 pre-amp (cheap dynaco) in my basement and it blows the pants off 85% of the systems at the local high-end joint.

I remain

Sean. A classic combo you've got in your basement if I do say so myself.

I run speakers I made myself. Based on Northcreek Rhythm Revelator basically (Northcreek.com).
Both of mine are moded too - really just replacing stuff though. Mine is very musical and I am sure yours is too. It is always good to listen to it because it brings me back down to earth. I don't think I have $1100 in the system, not including the source, which changes fairly often, and it does hold it's own.

Go for the classic tubes Dklap. Years from now it will be your second system because you will not be able to part with it. Good education too! (little more work now though)

Sincerely, I remain

Stratos: Heard it and I like it if you go for the SS sound. Good prices on used. Get the 120,000uF cap upgrade.

I remain,