Would increasing the gain in the amp give more weight to the sound? Any negatives?

The phono stage is AcousTech and the amp is Redgum RGi120, both SS.

well musical fidelity has inexpensive unity gain buffer device that also inverts the phase. one can be placed between the source and amp, but active preamp will work much more efficient than even mentioned inverting transformer. I struggled when I had Creek 5350 SE integrated amp till I purchased active preamp Classe 30. This preamp turned polite and shy Brittish amp into substantially better version...

Hi inna,
Your Redgum is a very low 10kohm input impedance, which could trouble some sources that have high’ish output impedances (eg >1kohm) this could be your problem if you phono stage is >1kohm.

I can’t find what the output impedance is of your Phono stage is, but I did find out just one of the few AcousTech phono stages, was designed by Ron Sutherland .

I just found this if it's your model.
"AcousTech Electronics PH-1 phono preamplifier "
" Recommended load: 10k ohms or greater"

You are right on the min, with the 10kohm of the Redgum if this is your Phono stage.

Cheers George

George, thank you very much. Yes, this is my phono stage. You see, the sound is not exactly lean, it is just not full enough.
So, I understand that increasing the amp's gain is a questionable idea that may do more harm than good. It's either putting active preamp between phono and Redgum or living with it as it is.

Inna, have you tried the two different cartridge loading options, as I remember back to the Supex SD900 days it preferred 10ohm loading to 100ohms as the 100ohms made it sound a bit too rounded.
You have plenty of output with the PH1 as it can give out 8v!!!, more than enough to clip any power amp, so you definitely don't need more gain with an active preamp.

Quote Stereophile on the PH1:" Input impedance: 100 ohms in parallel with 0.01µF (MC), or 47k ohms in parallel with 200pF (MM).

Cheers George