PS1 100X Audio mod, lacking bass

I listen to a lot of CDs and was thrilled when I realized that I had a 1004 PS1 in the basement which is suitable for the audiophile CD-player mod. I did the mod a long time ago and it sounds amazingly good. Unfortunately I feel that the bass is lacking, a lot.

On this site there's the information I followed to do this mod, but at the bottom it says:

The problem probably is that he's using an amplifier with a 22kΩ impedance, and my AVR has a 47kΩ impedance. I'm guessing I have to change the 22kΩ resistors between the signal pin on the RCA socket and GND to another value. However I find it all a little confusing and can't figure out what the correct value would be for my AVR.

I'm hoping someone will help me out, as the answer is probably quite simple

 

Trust me, if you want listen quality music buy a real hi fi stereo\ cd player. Stay away from that tutorial, you only destroy a very good model psx.
There are better equipment out there.

 

I already did the mod according to the site. The sound quality is much better than my Denon DCD-920. It's just that the bass sounds flat :/

 

Hook it up to some Logitech speakers.

What do you mean the bass sounds flat though, are you comparing to your Denon? Maybe the bass is over emphasized on the Denon?

 

Hooking it up to Logitech speakers would be a huge step down in quality.

Nope the Denon doesn't exaggerate the bass. It's pretty much the same if I play my CDs on a PS3 or Sega Saturn. In my first post I quote a bit where he says that bass cutoffs (flat bass) can occur if you use the wrong sized ground resistors. Which is probably what I'm experiencing here.

So what should I replace the 22K resistors with, considering my AVR has a 47K input impedance?