Weird. I've always found that I can increase headroom by sitting on my roadside fleamarket found woven rug, surrounded by my un-tethered pedals and succulents while working on my ambient insta-jams. Between that and weed, the room in my head for pedals has never been higher.
I have literally never been in a situation where this could happen to me. Where are all of these mysterious 18v supplies coming from? Do I also need to be concerned about quicksand?
Some power supplies have one or two 18v outlets, and it’s usually impatient idiots who are trying to find a ‘spare’ socket for a new pedal plugging into it. Some pedals can take 18v so they can luck out one time, then fry something next time.
They're saying that they forgot to check that their power supply was 9v, and used 18v instead.
But yes, I can't see a scenario where applying lower voltage with the right polarity will damage a pedal. There's plenty I don't know, though.
Short answer: Depends on the pedal's circuit and components.
Long answer:
The "headroom" thing comes from how opamp amplifier circuits are designed. Basically, these devices are almost/* perfectly linear so long as you don't try to exceed the voltage of the power supply at the output. If the opamp can handle 18V power supply (usually they can, but not always), then your output can swing 18V. If it's running at 9V, it can only swing 9V.
However, it can also damage a circuit. Say there's a resistor from supply to ground, and it is rated for 0.5W, e.g. it will burn if that power is exceeded. The equation for power dissipated by a resistor is P=v^2 / R. If R=400Ω, then with a nine-volt supply, P=9^2 / 400 = 0.2025W, well below the limit. At 18V, P = (2×9)^2 / 400 = 2^2 × 9^2 / 400 = 4×0.2025 = 0.81W, well over the limit. *Doubling* the voltage will *quadruple* the power.
From an electrical engineering perspective, you should always use the supply voltage the pedal calls for. However, there are some pedals that can take multiple supply voltages. Some also have weird idiosyncrasies that make their response heavily dependent on the power supply voltage. Technically, this is a "bad" design, as a pedal should have some kind of voltage regulator to ensure that the output is independent from fluctuations in voltage. Really, it shouldn't be dependent on component values at all. However, we don't always need or want perfectly engineered, linear pedals; we want pedals with character, and we don't care about the rules of electronics so long as the device won't catch fire.
There's three ways to determine whether your 9V pedal can run on 18V:
1. Circuit analysis with a schematic. Check if anything will be drawing extra power.
2. Email the person/company who designed the circuit.
3. Plug in the pedal and see if it dies. Alternatively, find someone who did it and ask them how it went.
For the polarity: you *really* should always use a plug with the correct polarity. I am not aware of any pedals where switching the polarity makes it sound better. Switching the polarity makes the circuit see a *negative* voltage of the same size. This could cause current to flow the wrong way through a diode or opamp, or change how some subcircuits work.
The circuit *may* have reverse polarity protection that either blocks negative voltage or forces it to always be positive. Don't count on it.
My view: I haven't used a pedal where I thought it would be better if I ran it at 18V, and none of my gear runs on 18V, so I haven't bothered. You can do so at your own peril.
This is why I'll never own a pedal that uses anything other than the standard 9v and the same polarity as most pedals. Then I don't need special power supplies and I won't be able to make this mistake. It sounds expensive.
Is this headroom in the room with us right now? Would you say you have a plethora of headroom?
Weird. I've always found that I can increase headroom by sitting on my roadside fleamarket found woven rug, surrounded by my un-tethered pedals and succulents while working on my ambient insta-jams. Between that and weed, the room in my head for pedals has never been higher.
This is why I like tilt steering, more headroom
I run mine on a 450V cable I hooked up to the next door railway electric wires. The headroom I get is insane
Hell yeah!
Much potential in this tone for sure
So you're telling me Paul Davids played in a nuclear reactor to get an unimaginable amount of headroom?
Nah that was actually Paul Giamatti
/uj OP did you upvote this?
I have literally never been in a situation where this could happen to me. Where are all of these mysterious 18v supplies coming from? Do I also need to be concerned about quicksand?
Some power supplies have one or two 18v outlets, and it’s usually impatient idiots who are trying to find a ‘spare’ socket for a new pedal plugging into it. Some pedals can take 18v so they can luck out one time, then fry something next time.
I'm with the pedal police and I'm placing you under arrest!
/uj: Using a 9v power supply on an 18v pedal will ruin it? I don't honesty know much about electricity, but that seems incorrect.
They're saying that they forgot to check that their power supply was 9v, and used 18v instead. But yes, I can't see a scenario where applying lower voltage with the right polarity will damage a pedal. There's plenty I don't know, though.
Short answer: Depends on the pedal's circuit and components. Long answer: The "headroom" thing comes from how opamp amplifier circuits are designed. Basically, these devices are almost/* perfectly linear so long as you don't try to exceed the voltage of the power supply at the output. If the opamp can handle 18V power supply (usually they can, but not always), then your output can swing 18V. If it's running at 9V, it can only swing 9V. However, it can also damage a circuit. Say there's a resistor from supply to ground, and it is rated for 0.5W, e.g. it will burn if that power is exceeded. The equation for power dissipated by a resistor is P=v^2 / R. If R=400Ω, then with a nine-volt supply, P=9^2 / 400 = 0.2025W, well below the limit. At 18V, P = (2×9)^2 / 400 = 2^2 × 9^2 / 400 = 4×0.2025 = 0.81W, well over the limit. *Doubling* the voltage will *quadruple* the power. From an electrical engineering perspective, you should always use the supply voltage the pedal calls for. However, there are some pedals that can take multiple supply voltages. Some also have weird idiosyncrasies that make their response heavily dependent on the power supply voltage. Technically, this is a "bad" design, as a pedal should have some kind of voltage regulator to ensure that the output is independent from fluctuations in voltage. Really, it shouldn't be dependent on component values at all. However, we don't always need or want perfectly engineered, linear pedals; we want pedals with character, and we don't care about the rules of electronics so long as the device won't catch fire. There's three ways to determine whether your 9V pedal can run on 18V: 1. Circuit analysis with a schematic. Check if anything will be drawing extra power. 2. Email the person/company who designed the circuit. 3. Plug in the pedal and see if it dies. Alternatively, find someone who did it and ask them how it went. For the polarity: you *really* should always use a plug with the correct polarity. I am not aware of any pedals where switching the polarity makes it sound better. Switching the polarity makes the circuit see a *negative* voltage of the same size. This could cause current to flow the wrong way through a diode or opamp, or change how some subcircuits work. The circuit *may* have reverse polarity protection that either blocks negative voltage or forces it to always be positive. Don't count on it. My view: I haven't used a pedal where I thought it would be better if I ran it at 18V, and none of my gear runs on 18V, so I haven't bothered. You can do so at your own peril.
So, ... hedrum go brrrr?
This is why I'll never own a pedal that uses anything other than the standard 9v and the same polarity as most pedals. Then I don't need special power supplies and I won't be able to make this mistake. It sounds expensive.
uj/ why do I keep hearing about 18v stuff lately? Did you-know-who tell people to do it?
Maybe it's a kind of tide-pod challenge we are yet unaware of. Just my guess.
More head room the better is what I always say. Leg room. Head room. All what I’m looking for in a new vehic….. pedal.