Coma
Well-known member
Maybe a stupid question, but how to these cables work? I understand that they combine the output of two connectors to one end point, but how does one double the voltage and the other the current?
Voltage and current doubler cables
- Thread starter Coma
- Start date
Chistopher
malapterurus electricus tonewood instigator
Don't use the current doubler cable. It puts voltage sources in parallel, which is never good to do long term
Chistopher
malapterurus electricus tonewood instigator
Also what problem do these propose solve
Coma
Well-known member
Let's say you have a power supply (the good multi-output kind, not a wall wart). Each output is rated for 300 ma at 9v.
You also have two pedals. Pedal A runs on 9v, but requires 500 ma of current to run. Pedal B only needs 100 ma, but runs on 18v.
Those cables allow you to connect two outputs to one input. So from your somewhat limited PSU, you can still send a total of 300 ma to pedal A, and a total of 18v to pedal B.
Bill Dennis
Active member
If I am not mistake, one runs the ports in parallel (doubles amps) and the other in series (doubles voltage)
Chistopher
malapterurus electricus tonewood instigator
I can understand wanting a quick and dirty way to convert 9v to 18v. But let's assume that you have one side 9.05v and the other side has 8.95v.
At that point you have 0.1v that's trying to flow from the high side to the low side, even if neither chord is plugged in. With batteries this isn't too major an issue because they will settle to a middle voltage if there's not too big a difference in voltages. With an isolated power supply they will constantly be fighting eachother.
Also that 0.1v may not seem like much, but it's 0.1v of near open circuit, so the higher power supply will be giving its full output when nothing is plugged into it. Might have heat issues too.
I don't know how big an issue this is and who knows, the engineers probably accounted for it. But if I have to use an iffy connection to make a pedal work with my powersupply on my board, either I'm not using the pedal or I'm upgrading my power supply. Or, the 3rd option, I'm using the high amp power supply that probably came with the pedal
Coma
Well-known member
To each their own. I've used both type of cables when needed and they worked flawlessly.
ehdwuld
A Ficus
That just seems like it will damage your power supply
My cheap power supplies have a bunch of isolated 9v , a 12v, and an 18v
Shorting two 9v together would just damage the power supply, don't you think?
Bill Dennis
Active member
I am not sure I followed the post you were questioning, but no, if you use them properly you are not shorting anything. They work fine and will not damage anything,. Its how it was done before supplies with higher voltage and amp capabilities came to the market. I still use them on a couple of my boards. Pedal power and others make them for just this purpose
2 outputs on the supply combine to either double amps or double the voltage. You need to keep in mind there are trade offs. Doubling the voltage also halves the amp. Two 9v 200ma outputs in series becomes 18v 100ma for example
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ehdwuld
A Ficus
Chistopher
malapterurus electricus tonewood instigator
It would be 18v 200mA because current is conserved in series.
