non-voluminous Prefix

Hi
I've finally got around to fitting my prefix(after 2 months of ownership-waiting for hicap and cartridge) now fed by a 100hr old (supposedly) expert stylus Troika.(bought from a naim dealer)
First off-- after 3 days burn(prefix is preused but just serviced )--is disappointment.
I suspect this is the Troika--it sounds just so laid back in the mid range(might post it to expert stylus for a check up)
But more of a concern is that the output to the preamp is so low.
My old AT OC9+ s boards without prefix was listened to at about the 12 o'clock vol control position
The troika + prefix needs the 3'oclock position for pretty comfortable levels in my small room.--not much extra for a blast---at max its no where near distorted--but I have neighbours just a wall away.I plan to move later this year(and rid my hifi of its 12th floor power supply--?40 fridges between me and the ground) ?won't be loud enough for a bigger room.

The natural hiss at this vol is very audible between the tracks and during quieter bits.
I did run very briefly the troika through old(42.5) k boards on my 72 and remember listening at 1 o'clock-I think.Cdi runs at 9-10 o'clock.
I've read somewhere on the forum that others found the prefix improved output vol--as logically you would thing it would.Unfortunatly swappimg back to th oc9 to test the prefix is tricky as I've soldered male pins(troika) to the arm leads.
Any thoughts?

The prefix is a K--and is powered by a snaps2
rest of system--lp12/aro/geddon 72/hi/naxo2-4/hi/160/250 active SBL's some Mana
Does anyone use the prefix with the older 72 with 2x 2 BNC inputs.--what lead setup do you have from the prefix *cap/snaps to the preamp?

Thanks in anticipation
Richard

PS the only major beneficiary to this upgrade is my cdi that sound better thro' a 72 with the phono board pulled from thro 72.
PPs will any non Linn cartridges work with K prefix ?lyra(i almost bought a lydian) ?Dynavector
that are a bit more upfront than my recon. troika