Should I use input trim?

[paulsue38]

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

 

[bandit pilot]

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

They are already physically in the signal path, so no, they shouldn't change SQ. The ability to level match all your inputs sounds like a good idea to me. I can tell you from my own system, which has no such feature, that I don't suddenly feel the need to go out and get it.

 

[RobHolt]

I guess the easy answer to this question is that if you need to ask others 'are the trimmers changing the sound', they aren't

Agree with Rick, they're a good idea.

 

[paulsue38]

Thanks for the replies. I have no idea how inputs work but in addition to making inputs louder they also seem to 'wake up' the music making it 'livelier' and perhaps 'brighter'? Are they actually acting like tone controls colouring the music?

Best wishes

Paul

 

[baltika_no_9]

Thanks for the replies. I have no idea how inputs work but in addition to making inputs louder they also seem to 'wake up' the music making it 'livelier' and perhaps 'brighter'? Are they actually acting like tone controls colouring the music? Best wishes

Paul

I had an A38 and used the trims so that when switching from phono to CD to AV etc, the sound levels were about the same so there was no sudden shock when moving from a quiet source to a louder one. I didn't notice any effect on SQ although switching from one source to another at different levels will change the way the sound is perceived that's why level matching is important when doing comparisons. For me input trims were a convenience. They're not intended to be tone controls, they're level controls.

 

[SergeAuckland]

I had an A38 and used the trims so that when switching from phono to CD to AV etc, the sound levels were about the same so there was no sudden shock when moving from a quiet source to a louder one. I didn't notice any effect on SQ although switching from one source to another at different levels will change the way the sound is perceived that's why level matching is important when doing comparisons. For me input trims were a convenience. They're not intended to be tone controls, they're level controls.

Spot on. A change in level will be perceived as a change in quality, for all sorts of reasons, not least Fletcher-Munson. A volume-trim unless heroically badly designed will change level only, so won't change any other parameter.

S

 

[SSM]

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.

cheerSS