Thread: Volume controls verses taps

Here's a question for you:

How come rotary volume controls on audio amplifiers etc turn the opposite way than a water tap/faucet to increase the output? I mean I guess the tap/faucet came first, so why did the first electronics engineer design the rotary volume potentiometer to operate in the opposite sense?

I've often wondered this.

OB

Originally Posted by One beer

Here's a question for you:

How come rotary volume controls on audio amplifiers etc turn the opposite way than a water tap/faucet to increase the output? I mean I guess the tap/faucet came first, so why did the first electronics engineer design the rotary volume potentiometer to operate in the opposite sense?

I've often wondered this.

OB

Fun question! My best guess is that the answer lies in the mapping between indicators (meters) and controls. It seems natural to arrange for the motion of controls to move meter needles in the "same" direction. This mapping, which was established in the earliest days of electrical power generation, established a precedent that carried over to the audio amplifier era.

I've encountered many hotel taps that increase flow when turned clockwise, btw. I've also seen lots of setups where cold and hot taps must be turned in opposite ways. There seems to be less uniformity there than in the case of audio amplifiers (I have never seen one in which the knob must be turned counterclockwise to increase loudness).

Perhaps the designer was right handed. In that case, with thumb and forefinger operating the control, the thumb would move upward, which is an easier movement than downward.

Psychology?
The "default state" of a water tap is off.
The "default" use of a volume control is to produce/ increase volume.
It doesn't matter if a volume control is on or off - with a tap it does.

Righty tighty, lefty loosey.
Same as machine screw threads.

(Note that there are important exceptions to this pattern.)

If you've ever used power amps and sound systems, I think you get used to always turning the sound source volume down to zero before switching them on - and this is certainly a reflex I have from working in broadcasting! You only blow tweeters once (and have to replace them) before this becomes automatic!

So far, I think tk421 has probably nailed it - the rotary volume control increases the signal level in the same sense as the traditional moving coil type of meter would show it increasing, ie, clockwise.

So I suppose my question really boils down to: Why are (most) taps/faucets "backwards"? And the answer to that is that they usually use right-handed screw threads, which results in the tap closing as it is screwed down clockwise.

Any thoughts?

OB

Originally Posted by One beer

So I suppose my question really boils down to: Why are (most) taps/faucets "backwards"? And the answer to that is that they usually use right-handed screw threads, which results in the tap closing as it is screwed down clockwise.

Any thoughts?

OB

It makes sense to me -- I buy that explanation.

electrical controls , in most cases are clockwise to increase, heat controls, clockwise for hotter, cold controls clockwise for colder (spent many hour's explaining that to laymen. saving our ship by closing the valve. that is spewing water from a broken pipe however needs to be reflexive....righty tighty, lefty loosey

When serving onboard ships, the valves we dealt with had hand wheels 2 feet in diameter closing gates on piping of substantial size. Opening is something usually done with care, closing in a hurry required the strength of the right hand pulling. Most electrical controls need no strength to manipulate, so less can be counter clockwise (which is "normal")

Originally Posted by keeseguy

When serving onboard ships, the valves we dealt with had hand wheels 2 feet in diameter closing gates on piping of substantial size. Opening is something usually done with care, closing in a hurry required the strength of the right hand pulling. Most electrical controls need no strength to manipulate, so less can be counter clockwise (which is "normal")

Yeah I can understand that. What is the proportion of right handed people in the general population - about 65%?

So making right handed screw threads would have made 'sense' to more people probably?

OB