Volume control comparison

Having seen numerous references to various ‘o-clock’ positions when users describe volume levels from various preamps, I’m interested in understanding how these equate to the digital 1-100 settings of the 272’s volume control.

I suspect they don’t equate as logically as one might assume? Does ‘quarter past’ = 25, ‘half past’ = 50 etc? I have a suspicion that the traditional controls may be linear, whereas the digital control of the 272 is more exponential, but I know next to nothing about electronics, hence my question!

The prompt for my question is that last night I experienced my first ever thermal ‘trip’ from my 250DR. It came after about 2 hours of much louder than normal music (home alone!), a volume setting of 60 on the 272, into my 4ohm ProAc K6 speakers. This was, to my ears, ‘head bangingly’ loud, and the maximum to which I would ever want to go - I would probably equate it to very loud party level requiring lip reading ability, were I ever to use my system thus (unlikely, as our social events at home tend to be of a more sedate nature!).

After about 20 minutes the case had cooled and normal service was resumed (at normal 35-40 levels).

They don’t equate in any way. Nearly all of the volume seems to be on the left hand side of the traditional volume pot, with a massive increase between 8 and 10 o’clock. The 272, in the other hand, increases smoothly. I occasionally run mine at 60 and it is really, really loud using my 300 in my 18m2 room. It’s fun for a short while.

If you assume the volume control on something with a conventional pot is going to be symmetrical about 12pm, so that 12pm is half way up, then that equates to 50 on a 0-100 scale and I would say 50 on a 272 is indeed quite loud. I normally run my 272 at 40. (Although all this assumes the same level source input.)

Best

David

I suggest you get a sound pressure level meter and get an idea of what pressure level corresponds to a given number

The digital volume control on my UnitiQute2 seems pretty linear. I don’t think that the analog control on my 252 is close to linear.

I’ve got the usual dB meter apps on my iPhone, but they don’t help me compare with, say, a 252 or 282 paired with the 250DR. Perhaps were an owner of one of those were to take a number of measurements at a number of positions using DecibelX or similar I could use those to give me an approximate comparison. I was hoping someone might know of a slightly more scientific comparison.

It’s all meaningless unless you have the same level of input signal. I’m not sure what you are hoping to achieve?

Best

David

Perhaps it might be simpler to ignore the sound levels, which I didn’t actually mention in the first place! I thought this was a very simple question, as outlined in my first sentences of my original post. How, if at all, do the varying positions on the traditional volume knob of traditional preamps equate to the digital volume indicators of the Uniti range and the 272? If the answer is ‘they don’t’ then that’s fine! I am just curious as to whether or not a reading of 50 on my display is equivalent to the 180° position on other preamps.

Then, you are fine! The usable range of the volume pot on a separate preamp is more limited. This can become more of a problem using the remote or, worse, the app to control volume. I find it a PITA, especially with easily driven speakers.

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Ok! I think my earlier answer applies then. Half rotation on a physical volume control is going to be about 50 on an electronic one.

Best

David

I don’t agree with that. 12o’clock with say a 282/250 would be deafening whereas with a 272/250 it wouldn’t be. I’d suggest sticking with the ‘no relationship’ answer.

This is interesting because the perception of loudness is not a linear but logarithmic relationship. Hence the need to use a sound pressure meter.

Both are log (or pseudo-log) law relationships.

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The Naim preamp (mechanical) volume controls use the 15A curve in the top right graph

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Lost me there, Xanthe! Once more in plain ol’ layman’s language if you please

Already done - see the post with the graphs (15A is a pseudo-log relationship).

I’m beginning to feel this is a question that should have been left unasked!

A log law response is one where, as the pot is turned, the rate of increase gets progressively more (in linear terms), such that the increase in decibels is roughly constant as you turn up the volume (i.e. the sound energy increases logarithmically)

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Got that! Now, how does the volume knob of the 272 perform in comparison?

You’ll need to ask Naim - they designed it.

Form my experiments it seems to be about 1.3dB per click, almost constant.

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