Author Options:

Looking for a gainclone design that's lower powered than most. What is the equivalent wattage at 16 or 4 ohms? Answered

Most of the gainclone designs i can find are between 25 and 50 watts. I have a pair of 20 watt maximum @ 8 Ohms which I'd like to build a small amp for (possibly portable, but gainclones don't seem to have much of that).
The downside: I understand making the Ohms match the minimum required of my amplifier, but I've never had to worry about the max wattage before. I know that if I attach them in series I get 16 Ohms and 4 if parallelled, but trying to figure out what the wattage becomes seems difficult. I know its logarithmic, but I can't find a calculator for it. Plus I think it depends on the amp's output ability.

(Yes I did mention these in another question.)



8 years ago

Connecting two speakers, either serial (16 ohms total) or parallel (4 ohms total), will double the wattage rating of one speaker. So the maximum wattage of the speakers together is 40, either way.

Generally speaking, If the amp can output 20 watts @ 8 ohms, a 4 ohm load will double the output wattage to 40 watts. And a 16 ohm load will halve the wattage to 10.

But it's dependent on the amp itself--there's usually an optimal load for power output. It's not unusual that an amp will dissipate more power with a bigger load, but only a percentage of that increase is output power. So it's best to look at the manuf specs for the amplifier.

Volume is logarithmic, not power. Doubling the power does NOT make the amp twice as loud.

Stay within the load ratings and you'll be OK.

Usually, it's best to mix and match speakers to obtain the optimum load, rather than adjust the output power.


Answer 8 years ago

I appreciate the notes and explanation of ohms versus watts but this doesn't help me find a gainclone that can match these. I guess I could find a mono <40 watt and tie the stereo together instead.


8 years ago

If you stick them 8 ohm 20 watt maximums in series, you get 16 ohms resistance 40 watt maximum, if you stick them in parallel you get 4 ohms resistance 20 watt maximum.