Author Topic: Watts vs Current  (Read 317 times)

Offline dflee

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Watts vs Current
« on: July 09, 2019, 07:01:19 AM »
I'm a complete novice when it comes to anything electric so am asking.
What makes a low wattage amp high current? And is a high wattage amp
high current in order to be high wattage or can you have a high wattage amp
with low current?
Just trying to figure something out. I've been told that a high current amp is good.

Don
ps: If this has been discussed before, please point me in that direction

Offline Barry (NJ)

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Re: Watts vs Current
« Reply #1 on: July 09, 2019, 12:13:30 PM »
Watts = Volts x Amps(Current)

Offline steve

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Re: Watts vs Current
« Reply #2 on: July 14, 2019, 08:21:27 PM »
I'm a complete novice when it comes to anything electric so am asking.
What makes a low wattage amp high current? And is a high wattage amp
high current in order to be high wattage or can you have a high wattage amp
with low current?
Just trying to figure something out. I've been told that a high current amp is good.

Don
ps: If this has been discussed before, please point me in that direction

Hi Don,

I believe many prefer higher current as linearity improves at lower current levels.
I say this because for just about any speaker, the limiting factor for current is the
signal voltage divided by the voice coil dc resistance, any inductor dc resistance, plus
speaker wire resistance and amplifier output resistance. Of course, there is inductance
with all resistances I just mentioned, so the current will be lower still.

What makes a low wattage amp high current is a combination of amplifier supply voltage,
power supply capacitance, and current that the output devices are safely capable of passing.

It is pretty difficult to have a high power amplifier with a low current rating, but it depends upon
what you mean by "low current" rating. I know that sounds like a cop out, but there are so  many
variables to deal with. As the speaker impedance rises (say 16 ohms), the current requirement
lowers, yet with higher voltage amplifiers, high power can be obtained.

I hope this helps Don.
steve

Steve Sammet (retired, owner, EE, SAS Audio Labs)
"V" Very Low Capacitance ICs
SAS Audio Labs Test Phono Stage
SAS Audio 11A Tube Reference Preamplifier
SAS Audio Labs 25 W Triode Reference Monoblocks
2 way test Spkrs, 28 - 20khz  -3db (28hz)