Inline attenuator detrimental to sound quality?

[Doobrey]

Any DAC that I have tried for my NAD C316BEE amplifier is too hot, volume can't be moved past 8-9 o'clock so for my current DAC Modi 3E I purchased the Rothwell RCA attenuators (-20db) and that lets me play with the volume up to about 12-1 on the dial. The problem is I think it has a degrading effect on the sound, there's like a congestion in the midrange so the instruments are blending and smearing together.

They are apparently "transparent matched resistors" so is that scientifically true and what I may be hearing i'm imagining? Would it be better to turn up the amplifier pot all the way up and get a dac with volume control instead?

 

[LTig]

This is strange. Even two standard 1% tolerance metal film resistors cannot add audible distortion of any kind to an audio signal at line level.

 

[sam_adams]

Did you purchase the 'for source' option attenuators or the input attenuators? Either way they would be unnecessary as the limiting factor in your signal chain would be the NAD with its ≈80 dB SINAD. You could drop the output signal level on the Schiit ≈30 dB and still be good.

 

[KMO]

-20dB seems like a huge attenuation.

A bit of searching leads me to believe the Modi 3E outputs 2Vrms for 0dBFS, which is pretty standard. -20dB drops that all the way to peaking at only 200mV, which is an unusually weak signal.

The manual of the amp says "Input sensitivity (ref. rated power) 200mV" and "Maximum input signal 7V".

It does seem it's an unusually high-gain amplifier - "Voltage gain 39dB". (And I thought the 29dB in AVRs was high!)

That all tallies: 200mV + 39dB = 19V = 40W into 8 ohm.

So it makes sense that without the attenuator, you wouldn't have to turn it up much. Whereas with -20dB in, you would now have to turn it all the way to the right and be receiving a very loud signal to be able to hit the rated 40W output.

None of that explains why you would be hearing issues - just wanted to dig into WHY you might want the attenuator.

Is the attenuator at the amplifier end of the cable?

Some discussion here might help: https://www.audiosciencereview.com/forum/index.php?threads/line-level-attenuator.24815/

I'd just settle for using only a small portion of the volume control range, personally, rather than add extra components.

 

[Blumlein 88]

Are you using a long cable after the attenuation? That might roll off the treble.

 

[Doobrey]

Did you purchase the 'for source' option attenuators or the input attenuators? Either way they would be unnecessary as the limiting factor in your signal chain would be the NAD with its ≈80 dB SINAD. You could drop the output signal level on the Schiit ≈30 dB and still be good.

No not the source option, these are directly input to the amplifier.

 

[Doobrey]

Are you using a long cable after the attenuation? That might roll off the treble.

1 meter amazon basics RCA

 

[Doobrey]

-20dB seems like a huge attenuation.

A bit of searching leads me to believe the Modi 3E outputs 2Vrms for 0dBFS, which is pretty standard. -20dB drops that all the way to peaking at only 200mV, which is an unusually weak signal.

The manual of the amp says "Input sensitivity (ref. rated power) 200mV" and "Maximum input signal 7V".

It does seem it's an unusually high-gain amplifier - "Voltage gain 39dB". (And I thought the 29dB in AVRs was high!)

That all tallies: 200mV + 39dB = 19V = 40W into 8 ohm.

So it makes sense that without the attenuator, you wouldn't have to turn it up much. Whereas with -20dB in, you would now have to turn it all the way to the right and be receiving a very loud signal to be able to hit the rated 40W output.

None of that explains why you would be hearing issues - just wanted to dig into WHY you might want the attenuator.

Is the attenuator at the amplifier end of the cable?

Some discussion here might help: https://www.audiosciencereview.com/forum/index.php?threads/line-level-attenuator.24815/

I'd just settle for using only a small portion of the volume control range, personally, rather than add extra components.

The problem is without attenuation the volume range is only between about 8 and 9 because 6-7 has right channel imbalance, there barely and movement between quiet and loud and can't use the remote because of it. with 20db attenuators inline I can move al the way up to 1 o'clock before it gets too loud.

The only other thing that maybe the issue is my speakers are too sensitive but it doesn't seem like it at 88db

There's a video here showing the same amp and speakers I have and there's no way id be able to go that volume he's using without the attenuators id be deaf in 10 minutes.

 

[KMO]

No, I'd say everything in your system aside from the amp is fairly standard. Your speaker sensitivity is quite typical, as is the DAC output.

It's the NAD that seems to have a bizarrely high gain to me.

-10dB attentuation would get you into "normal" range - 29dB overall, like a typical AVR.

-20dB seems acceptable - you can still reach the 200mV sensitivity for 40W - but it's right at the limit.

Can't offer any useful suggestions on why the attenuator would upset anything. Can you limit volume upstream of the DAC instead?

 

[Doobrey]

If im listening through optical out of my Sony TV I have the option limit the output which is currently set to max but can be adjusted from 100-0

any source i've tried though has the same problem with high gain.

 

[Ken Tajalli]

See my reply on the other thread you asked a similar question.
I wonder if you have plugged the DACs into an incompatible input port.