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In Reply to: RE: It's not the watts, it's current.... posted by Tre' on August 05, 2020 at 19:01:51
I understand the math and in a perfect world, yes, an amp should double the power or watts in going from an 8 ohm to a 4 ohm load and double again into 2 ohms.
For example, the specs for a Yamaha A-S801 reads like this:
Watts RMS per Channel (8-ohms) 100
Watts RMS per Channel (6-ohms) 120
Watts RMS per Channel (4-ohms) Not given
So, how do you explain the fact that many amps can not handle lower impedance loads?
many amps were not designed to double the power at a load as low as 4 (or again at 2) in reference to a stated distortion level.
The doubling of power is a cost consideration as the power supply etc for doubling adds extra $$$.
"Bass is the place..the rest is filigree and lace" Doug Sax
I have used my 3.6 with a 2x45 W (4 Ohm) receiver. Room is 21 m2. It is a surprise how little power that goes inte them with todays loudnessraced music. Very good recordings with good dynamics is a different story. So far, I have never clipped the 4x180 W (4 Ohm) power amps I use today. Active drive increases the effiency by about 1.5 dB for the basses.
You're not addressing Tre's point.
You said "it's not the watts......"
Yet, in your real-world example, you're clearly showing it IS the watts (de-rating.)
If power amplifier current capability de-rates at lower impedance loads then, by definition, so does the wattage capability.
Yes, and that was my point entirely. All 100 watt amps are not equal. Having to de-rate their amp points toward a lesser power supply that can't handle difficult loads.
"All 100 watt amps are not equal."
You can say that again, and in many different ways.
A lot of SS amplifiers have lower distortion at 2 watts vs. .2 watts. The problem with that is, with most speakers, we listen to .2 watts a lot more of the time vs. 2 watts.
To your point, an amplifier that can not double it's output watts each time the load impedance is halved is showing a lack of current delivery ability.
I would have said it like this, 'It's not the rated watts into 8 ohms that matters so much when we are talking about driving speakers that have an impedance curve that dips well below 8 ohms, it's the wattage rating of the amplifier when driving those lower impedances vs. the wattage rating into 8 ohms'
That says what you were trying to say without making it sound like 'watts and current' can be separated.
Have Fun and Enjoy the Music
"Still Working the Problem"
I tend to over simplify.
What would you call an amp that can double down to 2 ohms, a high current amp?
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