Question regarding "loudness" switch

The loudness switch is for listening to music at lower volumes.

If you look at the classic Fletcher Munson equal loudness curves, you'll see that our hearing is "flatter" at higher levels and not so flat at lower levels.

At lower levels, we're less sensitive to lower frequencies and higher frequencies compared to midrange frequencies.

The loudness switch adds a bit of bass and treble boost in order to help compensate for this.

So don't use the loudness switch when listening at normal levels.

se

It shouldn't do anything more than give a bit of bass and treble boost. If it's behaving like you're describing, it may well have a problem.

se

what exactly is inaudible to you? lot of people are so use to loud sound pressure levels of over 90db nowadays that even little touch on the knob is considered quiet. if the woofer is still causing a nice excursion with the loudness switch on then the volume is not low enough. it shouldn't be doing that. it only boosts the bass and treble at below human hearing sensitivity,nothing else. some amps too slowly cuts off the loudness switch when higher the volume knob is raised. having the loudness switch on at moderate to high volumes can greatly stress out the amplifier and possibly kill the speakers.

Quote:

Originally Posted by Ckaz 

Is it then possible that my loudness switch is really, really broken? Because even when I'm playing at nearly inaudible levels,

Based on a distant memory, when most of my amps had a loudness switch, I think that some models overcompensate the frequency contours and some actually boost the total volume. 

That was not the original purpose of a loudness switch (which was as se posted), so I assume some deliberately exaggerate the feature just to make sure the listener hears a difference.

a good loudness switch, and tone controls, should tail off as the volume is increased so as to not nuke your ears or overwork the amplifier (all the intense low freqs require more ooomph), both Yamaha and NAD do this i think (don't quote me :P).  Good tone controls are an absolute blessing that seems to be scorned for some reason, even as far as to call their omission a 'feature'.

from what you describe it sounds broken, perhaps the caps in your amp need replacing or something, i just recently redid (caps, resistors, Qcurrent and offset, random other stuff) an nad C300 amp i bought off ebay and the over-the-top speaker movements have stopped :D

Aren't you over driving the amp a bit with 6ohm speakers, when the amp is rated at 8ohm , it should be ok unless you really push it but maybe thats why the loudness switch cause disortion.

The amp probably has good output below 8 ohms, shouldn't be a problem. Sometimes, on lesser receivers and amplifiers the loudness function was more of a gimmick. Just leave it off, ignore it. 

Maybe just a dirty pot. Turn the amp off and run the pot clockwise/counterclockwise several times and see if that doesn't help. If not, you'll probably need some Caig: http://store.caig.com/Quote:

Originally Posted by Ckaz 

Well I'm also having a problem that when I turn up the volume there is crackle out of the right channel. It only happens when I move the volume knob though.

It makes me think that there are a few things wrong with the amp, and I've been meaning to learn how to do this kind of DIY, so what better time then now.

 

Any suggestions?

take the volume knobs off and blast them with some electronic cleaner from radioshack or deoxit you find at a local music store or retail store with electronics. the volume knobs should just pull off fine. with switches just blast them and keep pressing the switch on and off allowing the cleaner to soak in. also can blast the pcb boards as well inside connectors. give it the works and she be running at full spec in no time. that's if it's just cleaning to be done. lot people don't mention this enough but you probably might need your current bias re-tuned also. one of the output speaker channels can be outputting far more current then the other causing the speakers to distort and will end up burning the voic coil of your speakers if slammed with high amounts of current through them.

well it's next to the tuning flywheel (big silver round thing on the far right)  might be behind a circuit board, i can't tell...