non-inverted tone control?

[otaku]

Hi, diy community people,
I have an old crown preamp based on 70's op-amps and looking at its schematic, noticed one thing strange.
schematic

It uses one single channel op-amp for each channel in non-inverted configuration, and it has tone control feature. As far as my limited experience tells me, I've never seen tone control circuit in this configuration, which amazes me a bit. All circuits I saw had inverted tone control then another inverted unity gain for phase correction..

Perhaps the engineer of this unit wanted to minimize the number of op-amps by non-inverted tone control followed by no 2nd stage. Is it considered a good technique, I wonder?

I'm also feeling this preamp sounds very dry. Basically it has no gain throughout the circuit which makes it sound dull, I suppose? There's a switch I can select 0db and -10db. At 0db, I could hear noticeable noise. Replacing with OPA627 didn't help.

Any suggestion for possible mod and opinions on the circuit design will be truly grateful. Thanks,