Difference in SPL among amps

[killdozzer]

If all else is the same, only thing being changed is my amp and all of a sudden I have to go to "2 o'clock" to get the same SPL as oppose to 10 or 11 o'clock position on a former amp, what is my usual suspect? Where should I look first?

Amps in question are NAD and Marantz, they're both good, respectable, reliable and as I said nothing else changed; same source, same speakers, same set up all together, but with Marantz the speakers are very quiet. If you want to get some loudness you have to turn the knob to almost twice the amount; 1/3 on a NAD and you're thinking will the neighbors come knocking, with Marantz 2/3 and you're thinking meeeh, probably not.

What makes up for this difference?

TIA

 

[ryanosaur]

Are the gains and input sensitivities the same?

 

[Verdinut]

If all else is the same, only thing being changed is my amp and all of a sudden I have to go to "2 o'clock" to get the same SPL as oppose to 10 or 11 o'clock position on a former amp, what is my usual suspect? Where should I look first?

Amps in question are NAD and Marantz, they're both good, respectable, reliable and as I said nothing else changed; same source, same speakers, same set up all together, but with Marantz the speakers are very quiet. If you want to get some loudness you have to turn the knob to almost twice the amount; 1/3 on a NAD and you're thinking will the neighbors come knocking, with Marantz 2/3 and you're thinking meeeh, probably not.

What makes up for this difference?

TIA

The difference has to do with the different sensitivity for full rated of each amplifier. Assuming that both amplifiers have the same power rating, it takes a higher voltage output from the preamplifier for the Marantz to reach about same output as that of the NAD. There's nothing you can do about it, unless the Marantz is defective.

We should search for the full specs of each one to confirm my assumption. Supply me with the model number of each product, and I will be pleased to look for those specs.

 

[lovinthehd]

Why would the volume controls be the same?

 

[killdozzer]

Thank you all.

@Verdinut Thank you. The NAD is older, I'll have to look for the specs, but will do.

@lovinthehd Not that they should be the same, but the described situation makes you think Marantz lacks power and you start thinking why? Also, it makes you wonder what would you need to do to go to reference levels or would it ever get there?

 

[slipperybidness]

If all else is the same, only thing being changed is my amp and all of a sudden I have to go to "2 o'clock" to get the same SPL as oppose to 10 or 11 o'clock position on a former amp, what is my usual suspect? Where should I look first?

Amps in question are NAD and Marantz, they're both good, respectable, reliable and as I said nothing else changed; same source, same speakers, same set up all together, but with Marantz the speakers are very quiet. If you want to get some loudness you have to turn the knob to almost twice the amount; 1/3 on a NAD and you're thinking will the neighbors come knocking, with Marantz 2/3 and you're thinking meeeh, probably not.

What makes up for this difference?

TIA

Just different gain and different gain structures. This is normal.

As long as you can get to the desired volume without distortion, there is no problem here. The volume knob position is absolutely arbitrary.

The volume knob is better described as a "signal attenuator", if you take it in that context and review gain/gain structure, it should all make sense.

 

[killdozzer]

Just different gain and different gain structures. This is normal.

As long as you can get to the desired volume without distortion, there is no problem here. The volume knob position is absolutely arbitrary.

The volume knob is better described as a "signal attenuator", if you take it in that context and review gain/gain structure, it should all make sense.

Thanks man. I'm officially done with worrying. It made me think that Marantz is somehow inadequate, struggling or something along those lines.

 

[killdozzer]

@Verdinut here goes:

 

[PENG]

@Verdinut here goes:

To explain the difference, we need to know the NAD's model number as well. As mentioned by others already, the input sensitivity and gain of the amps are likely quite different.

Also, if the Marantz is a more recent model, it's volume control is likely of the log scale type, whereas the NAD, if a much model, will likely linear, to you don't need to turn it up as high. My little NAD amp gets quite loud at 10 O'Clock, and would probably explode if I crank it up pass 2 O'clock. You can't compare the power output capability of amps by the volume position to get to a certain spl only, Either you take proper measurements, or at least take the difference in input sensitivity and gain into consideration and do some math.

 

[Verdinut]

According to the specs, the Marantz PM5005 has a high input sensitivity of 200 mv/20kOhms. Is it possible that it is defective, due to the fact that it doesn't seem to produce much output compared to the NAD, which I presume wouldn't have a higher sensitivity?

 

[PENG]

According to the specs, the Marantz PM5005 has a high input sensitivity of 200 mv/20kOhms. Is it possible that it is defective, due to the fact that it doesn't seem to produce much output compared to the NAD, which I presume wouldn't have a higher sensitivity?

As I said, perhaps the Marantz has a log scale volume pot. If not, then I would agree there is something else going on.

 

[Verdinut]

As I said, perhaps the Marantz has a log scale volume pot. If not, then I would agree there is something else going on.

I haven't used that many amplifiers, but I don't remember having noticed large difference in the ones I had been using.

Is that common for integrated amps to use a log scale volume pot? From your experience what would be a probable percentage for each configuration?

 

[M Code]

I haven't used that many amplifiers, but I don't remember having noticed large difference in the ones I had been using.

Is that common for integrated amps to use a log scale volume pot? From your experience what would be a probable percentage for each configuration?

IMHO... Most amplifiers that use a potentiometer and/or AVR/processor that uses an audio/DSP chip the amount gain vs. % rotation is not linear..
Since U want fine volume adjustment for the 1st 60% of rotation is typically is done in small increments to provide a wide range of adjustment..

Just my $0.02...

 

[<eargiant]

According to the specs, the Marantz PM5005 has a high input sensitivity of 200 mv/20kOhms. Is it possible that it is defective, due to the fact that it doesn't seem to produce much output compared to the NAD, which I presume wouldn't have a higher sensitivity?

200mV is not high, it's a Goldilocks sensitivity. All things being equal, my guess is that his NAD has a higher input sensitivity of ~150mV which was common with those units.

200mV is a lower sensitivity than 150mV.

 

[mtrycrafts]

You can also do an experiment to satisfy your curiosity, if you have a good voltmeter.
Play a test tone CD say at 60 Hz, measure voltage at the speakers, record voltage and volume setting.
Repeat with the 2nd receiver.
You can also check at a 1 kHz and do the same.

 

[Verdinut]

You can also do an experiment to satisfy your curiosity, if you have a good voltmeter.
Play a test tone CD say at 60 Hz, measure voltage at the speakers, record voltage and volume setting.
Repeat with the 2nd receiver.
You can also check at a 1 kHz and do the same.

This would measure the different results of the two amplifiers, but not really explain reason for the difference in perceived volume.

 

[killdozzer]

Thank you all.

To explain the difference, we need to know the NAD's model number as well. As mentioned by others already, the input sensitivity and gain of the amps are likely quite different.

Also, if the Marantz is a more recent model, it's volume control is likely of the log scale type, whereas the NAD, if a much model, will likely linear, to you don't need to turn it up as high. My little NAD amp gets quite loud at 10 O'Clock, and would probably explode if I crank it up pass 2 O'clock. You can't compare the power output capability of amps by the volume position to get to a certain spl only, Either you take proper measurements, or at least take the difference in input sensitivity and gain into consideration and do some math.

I know, it's just that I wanted to upload the doc from hifiengine, but it's to big. The model number is 314 for the NAD. Since the file is too large, could you please read it on hifiengine? I don't want to be demanding, but I couldn't upload it.

 

[PENG]

I haven't used that many amplifiers, but I don't remember having noticed large difference in the ones I had been using.

Is that common for integrated amps to use a log scale volume pot? From your experience what would be a probable percentage for each configuration?

I Googled and could not find anyone talking anything about "%" split. In my experience, "many" older generations (say at least 15 years old just to be conservative) preamps and integrated amps probably have some form of linear taper pots, or at least leaning towards linear. I would really want to say "all", or "most" older generations....but I don't feel I have listened to enough preamps and integrated amps to say it.

Attached is a photo of my Marantz preamp's volume position when I listen to music, paired with the matching power amp. My much less powerful NAD integrated amp vol position would be just a little higher even though I sit much closer, but still only at 10 O'clock most of the time. If I use the much newer oppo devices and the Cambridge Audio preamp, the MV position (digital), would be much higher as they obviously adopted some form of logarithmic taper.

The linked article explained the various curves nicely if you are interested.

http://www.geofex.com/article_folders/potsecrets/potscret.htm

 

[killdozzer]

If I use the much newer oppo devices and the Cambridge Audio preamp, the MV position (digital), would be much higher as they obviously adopted some form of logarithmic taper.

This is my experience as well; newer are almost always the ones you need to turn up much further to get it loud (I know how imprecise all of this is).

OTOH when I was a kid I remember always wondering why do amps even have the possibility to go beyond 12 o'clock if it's always too loud there.

 

[<eargiant]

This is my experience as well; newer are almost always the ones you need to turn up much further to get it loud (I know how imprecise all of this is).

OTOH when I was a kid I remember always wondering why do amps even have the possibility to go beyond 12 o'clock if it's always too loud there.

The input sensitivity on the NAD 314 is even higher than I expected in post #14. It is 0.97mV which is VERY high. It was probably done to compensate for the units low power rating of 35 WPC. The higher sensitivity will make it seem more powerful.

This confirms what you are experiencing.

Lower sensitivity is better. I would take a 200mV sensitivity over a 0.97mV sensitivity any day of the week.

EDIT: The line level input is rated at 170mV so I was close. This is still higher than the 200mV of the Marantz so it confirms what you are hearing.