Does anyone know where I can get one to limit the volume on a stereo without having to sit there with a stick?
Don’t really understand your question. What are you doing with your stick? Are you wanting a stereo that will turn itself down for the loud bits on your album and turn itself back up again for the quiet bits?
Is this what your looking for?
Costs $149.00
If it is, you might search google for “automatic sound leveler” and find one cheaper.
OOPS!
Sorry, the price should have read $249.00, plus you also might need the 24v power adapter.
Wow. That’s a ripoff.
What you are probably looking for is called a “limiter”. Strangely enough. Price ranges run the gammut, but you can get fairly cheap ones on e-bay. Like this one.
Limiters are usually used by people who record, or musicians, they’re not really home audio equipment, though I see no reason why you couldn’t use one with your stereo.
A compressor/limiter is what you’re looking for. But, it’s a line level device so you’d have to place it between the CD player and the amp (or the tape deck and the amp). You couldn’t place it say, between the amp and the speakers.
Also, I wouldn’t put down the stick so fast. What would you do in case of rabid badger attack?
Better explanation: How can I stop people from turning the output up to “11” on a stereo - no matter how much they play with the volume knob - without having to sit there with a stick?
A fuse on the speaker wires would do the trick but the tolerance on a standard fuse is horrible. If you can find fuses with a decent tolerance they’ll blow at about the same level each time.
Um… Get a lower powered amp?
Would this be a situation that arises at, say, parties, barbies etc? Where every second person passing the amp turns it up a tad?
First of all do* not * use a less powerful amp - a wimpy amp driven into clipping not only sounds God-awful but can shred your speakers.
The fix I came up with was to put resistors in series with the volume pot - (one resistor per channel) cost about 4 of the Queen’s own pennies.
The best thing to do - if you can find a friendly geek who knows which end of a soldering iron to hold and can be bribed with beer - is fit variable resistors (“pots”) inside the amp, same value as the original volume pot should work if they’re connected in the same way (one end signal, other to earth). The wiper of the “trim-pots” would now feed the original volume pot (at its signal end) and you can set the max level you want.
If you’re only using one input of the amp you could put the pots on the input - and have them external so you don’t have to open your amp.
Confused? It’s the best I can do without resorting to ASCII-art I’m afraid, but if you can find someone who knows a little about basic electronics they’d get the idea quick, don’t give them the beer before they start hacking into your amp though.
As mentioned above you want a limiter. Often used in clubs and arenas when sound guys touring with the bands can’t be trusted anymore than your party guests. Example. (this is not a recommendation - just an example, I’ve never used the linked product)
Ye-e-e-e-s-s-s. It’s actually for a gym where the instructors keep going for 11. I want something to set a maximum decibel level no matter how many knobs they twist.
Yes, confused. I didn’t understand a word of that. Could you make a box that plugs into the amp output and send it to me?
Opengrave All that goes straight over my head like an F111. Whoosh! And I thought I liked technobabble!
Stop inviting Spinal Tap to your place:).
A technobabble explanation of limiters here. Go to the section titled Reign Over Your Volume near the bottom. Others share your problem.
NP: Opeth - Deliverance
I think B. Phart’s suggestion is the best so far, although it requires technical expertise. If I understand correctly his suggestion is basically this: put a volume knob inside the amp so no one can get to it, and set it to what you think the maximum level should be. Now when the perpetrator turns the volume knob on the outside of the amp all the way up, the maximum volume will be what the inside knob is set to, not the full volume that the amp is capable of.
I don’t know if the stereo in question is an all in one unit or components. If it’s all in one, then a compressor/limiter can’t be used.
Sorry about my earlier flip answer. However, I was quite serious in wondering why you have an amp and speakers that are much loder than you want. Smaller amps and speakers do not automatically lead to clipping. Clipping occurs when the amp is poorly designed to allow you to ‘turn it up’ beyond the range it can handle well. Almost all amps do this on the principle that different audio inputs will clip at different levels, depending on factors like spectral composition. However, most go up to the point where there any sound will clip, which is foolish.
In short: why is there even an ‘11’ on the dial, if the amp can only handle 10? Marketing.
However to clarify the advice given above, you can modify the ‘volume knob’ yourself quite cheaply and reversibly, if you know a few basic principles. First off, you should understand that the volume knob or slider is almost always a variable resistor called a ‘potentiometer’ or 'pot ’ which is rated by its maximum resistance (in ohms) and can be set to any value from zero to that maximum
The commonest kind of potentiometer consists of a fixed resistor and a movable slider or wiper that taps the resistor somewhere along its length (i.e. it’s in the middle). It has 3 terminals, one for each end of the fixed resistor (call them A&B), and one for the slider. Sometimes you’ll see two or more of these pots [or maybe a rotary switch] stacked up so that turning one knob turns all of them simultaneously. This doesn’t affect the basic principles.
The wiper (middle terminal) is the interesting one - the one with the changing resistance. Most circuits only use A or B, and clip the other fixed terminal. Why? Because if you use A and B, you’re just using the pot as a fixed resistor, which is boring and pointless.
Captain Phart was saying that you can easily change the potentiometer’s range. Bear with me. This is easier than it sounds
There are two ways of hooking up two resistors. You can hook them up side by side (“in parallel”) or ine after the other (“in series”). If you hook them up side by side, it’s like opening up a second checkout lane at the grocery store, and total resistance goes down. If you put them end to end, it’s like hitting two traffic lights on the way to work, instead of one, and resistance goes up.
More precisely, series resistances add directly: R1 + R2 = Rt
While the inverse of parallel resistances add: 1/R1 + 1/R2 = 1/Rt
(I won’t explain why. There are plenty of sites for that, if you care)
This means:
A) if I want to keep the resistance of the volume knob from going all the way to zero, I can solder a resistor between the wiper terminal and the wire that ordinarily connects with it. It’s very basic, really: by putting, say 1000Ω after the potentiometer, I’ll never have less that 1000Ω on that wire. No matter how low your guests twiddle the knob, they can’t twiddle the fixed resistor you put in.
B) If I want to limit the maximum value of the potentiometer, I can put a resistor in parallel to the potentiometer, by soldering it to both the fixed terminal and the wiper terminal. No matter how high your guests turn the knob, they can never turn the resistance higher than the resistance you put in. Thing of it this way: you can put the wackiest most erratic trainee at a cash register in parallel to an experienced clerk, but the two registers together will never be slower than the experienced clerk at the first register. [Okay, in real life, idiot clerks slow down the other clerks with questions, but let’s say the manager is riding herd on her]
Putting a resistor in parallel with the volume control limits the maximum total resistance. Putting a resistor in series with the volume control limits the minimum total resistance.The volume control will still vary the volume smoothly over its new range, and since “resistance is resistance” regardless of its cause, the rest of your amplifier circuit won’t even know you changed anything. It’ll obey the resistance it sees, believing it’s just the usual volume knob
The other thing Captain Phart mentioned was “trim pots”. A trim pot is just a small cheap potentiometer without a nice knob. They are used to make adjustments that are rarely changed. Often circuits use trimpots that are adjusted once at the factory and never again.
One final detail, which shouldn’t matter much on a volume control is the wattage rating of the resistor or pot you add. A 1/8 W resistor the size of a grain of rice may not be able to handle the job (but frankly, it may). a 1/2 or 1W resistor is probably overkill, but its cheap and pretty small, so rather than discuss the math, that’s what I’ll suggest. There are various types of resistors - carbon, wire wound, etc. and different precisions. Ignore them a good quality carbon resistor (the cheapest kind) should work just fine,
So now you know, in principle, how to modify your volume knob so that it has a maximum or minimum volume, regardless of how much anyone twiddles the knob.
I like the stick idea better myself. Or perhaps a very stern sign. 
KP: I’m fine with a screwdriver but a soldering iron is too much like a light-sabre so I would prefer something I can plug in at the back of the amp.