I have an Arcam A38 that has an input trim facility. This clearly makes each source selected louder if adjusted but is it also 'changing' the sound quality and if so to what degree and should I use them at all? Paul
Use it if you find you're not generating the volume level you require, from the chosen source. I had this problem during opera music with my A28 when it was paired with Spendor S3/5R (an insensitive 82dB). At one point I got up to 65 (out of 72) and the soprano was barely screaming loud enough at me. :nup: I then activated the A28's trim to 8 and could then get decent level for that 65 mark. This was a rare incident where the Spens sapped nearly all the volts from the A28 for an admittedly average quality opera recording, but I remember the ridiculousness of the situation.
And no, to my ears when I maxed the trim function the sound from the source didn't seem to change i.e. get brighter or bassier. Still, for purist sake, I prefered to keep the trim to 0.
I just encountered the same issue on Sunday when I hooked up my Playstation3's analogue line out to my fresh A38. Compared to the connected rDAC (which was loud enough at -40dB), I had to crank the PS3's up to -25dB to match the rDAC levels. :shock: I surmised this softness is due to the A38's rather low input impedance which is probbaly cruel for the PS3's line out. The PS3 is usually connected to my Icon pre and its level is quite matched with the M-DAC when I switch between them.
Racking up the A38's trim to +12 improved matters for the PS3. There then at -35dB, the PS3's level was about on par with the rDAC's at -40dB. Again no, the trim didn't change the sound quality of the PS3 imo.