Please recommend a receiver/integated/seaprates for JBL studio 530.

Yamaha makes some nice integrated amps in your price range. I had one driving my older IMF's that I was happy with. Gave it to my son when I got classic Marantz separates.

Crown power amplifier and Semoic Audio 6j1 tube preamplifier. 
Depending on which Crown you get, you can easily stay under $500, especially on Amazon.

I’ve got their 145 RMS WPC version and paid $249 for it used. They still have a couple more in stock. 

The preamp only costs $14.64

If you need an FM tuner, there’s a fabulous bargain in the Minlia HDTV FC0012 USB RTL 2832U SDR Tuner dongle stick DBB-T + DAB + FM + TV receiver. $16.89 plus tax on Amazon. See my post in the “diminishing returns” forum thread for why I like it. 

There is a used Denon DRA-355 on ebay this morning for $55. FYI

Lots to consider here, guys, except for the $14 tube pre-amp bob suggested.  that's just plain scary!!!!!   

I agree with blainer55 on Yamaha. There have been quite a few mergers in the home theater integrated amp market, including Denon with Marantz who were subsequently purchased by Sound United LLC and Pioneer bought by Onkyo. Sometimes (but not always) with the mergers, the new owners use cheaper components because all they were really after was the name. Yamaha has remained independent and has the highest reliability ratings of any home theater integrated amp manufacturer. I've read about quite a few problems with Denon HDMI connectors and other issues with the other manufacturers. I rarely if ever read about problems with Yamaha. My suggestion would be to look for a previous year's model that has everything you want but has been heavily discounted.