Phono pre amp

A Phono Stage search on Aliexpress will show a vast range of designs in both SS and Valve/Hybrid and Valve Input / Output. 

Monies asked are very very fair, there can be a wait of a few weeks for a delivery.    

I've had both Rega and Schiit. Rega sounds better to my ears at comparable prices to Schiit. Rega Fono Mini is $195.00 brand new.Rega Fono MM is 445.00 brand new and Rega Fono MC is 555.00 brand new. I'm sure used prices will be around your budget.

I eventually upgraded to the Rega Aura.

Schiit Mani 2 -  $160. Michael Fremer of The Tracking Angle likes it!

An alternative to the Schiit models (which I happen like as well), you might want to look at the Parasound Zphono's, which you can pick up used for <$200.

Presumably your INT has a built in PS?

What is your amp and phono rig? 

I ask because for $650 + $150 shipping you could get a killer tube phono that will very likely beat anything built in.

Although the delivery timeline may be a non-starter. They only make a finite qty each month.

Softone Model 4 (made in Japan)