US amps power output

[ToyTundra 10+ year member]

I was reading This PDF about the USA-50 and 50x amps. This is what i found and it confused me:

...

Rated Amplifier Output @ 4 Ohms per Channel:

USA-50: 50 Watts

50x: 100 Watts

...

SPECIFICATIONS:.........USA-50........................ 50x

Watts/channel

4 ohms:.......................25 Watts..................50 Watts

2 ohms:.......................50 Watts..................80 Watts

1 ohm:.........................80 Watts..................N/A

Bridged Output: 160 Watts 160 Watts

THD:
S/N Ratio: >100db >100db

So my question is whats going on? Do they use the lower power rating to keep that crazy low THD? Are they underrated by half, but they also tell actual rating(top quote)?

I've always wanted to try US amps' gear, but i dunno which rating to believe

http://www.usamps.com/old_site/technical/documentation.htm

Click to read more...

 

[squeak9798 5,000+ posts]

The first quote tells *total* amplifier power @ 4ohm per channel.

(25*2 = 50, 50*2 = 100)

The 2nd quote tells power per channel output at a given impedance.

 

[ToyTundra 10+ year member]

Oh. The first way is retarded.

 

[guy022077 10+ year member]

wayyyyy underrated...i had the us 100 and us150 and ran 4 comp sets and 4 10's they get SUPER hot the 150 shut down every once and awhile but i had no cooling.

 

[chinny 5,000+ posts]

the USA-50 and the USA-50X are diff amps, the 50x has more power than the 50 but they are both way under rated anyways

 

[ToyTundra 10+ year member]

How underrated are they 10%, 20%, 40%, more?

Once i measure my current draw i'll decide if i should run a ~40-50 W (tweet) amp or a 100-130w (mids) amp.

 

[MrWizzard 10+ year member]

wayyyyy underrated...i had the us 100 and us150 and ran 4 comp sets and 4 10's they get SUPER hot the 150 shut down every once and awhile but i had no cooling.

Probably cause you're running them at lower impedance than they can handle.... 4 comp sets? on one amp? hehe.

 

[ToyTundra 10+ year member]

How underrated are they 10%, 20%, 40%, more?

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