Upgrade from Pio Elite A 35 R intergrated and Pio Elite SC05

I have collected some of the cans that have been recommended from this forum, I would like to say thanks to all the folks who have

contributed to this forum that make my journey of HPs learning process much easier.

Now I am ready to be enlightened with your knowledge of HP amps. Bias or unbias alike, I would like to hear from you . Currenlty, Im use the Pio Elite SC05 jack for movies or soundtracks and I am okay with the set up.

As far as2 channel audio, I use the Pio Elite A35R jack for 2 channel audio. My sources are the Pio BDP 51F with Wofsondacs and the Sony Viao laptop. My cables are the Kimber PBJ and the Silverstreaks,

I know there are much better dedicated HP amps on the market if budget is no object but being an old man with fix income, I would  like to have a dedicated HP amp either tubes bases or SS and my budget will stay under $500.00 ,

I like fast, attack sound signature of Krell amps.No HF roll-off , please.I do not like bloated midrange or heavy bass. Is there a headphone amp within my budget that will improve the SQ of my Pio Elite A 35 R. 

Thank you.