Your simulation shows fairly low distortion and a peak voltage of 20V into 8 ohms. It also shows 50W peak which is not a sinewave but instead is a short duration narrow pulse.
Then the output RMS voltage is 20V x 0.707= 14.14V and the output power is calculated as 25 continuous RMS W.

Audio is AC so the output power is RMS, never peak.
The datasheet shows the LM1875 is heating with about 20W, not 52W.

 

Post your schematic.

If you using a single supply voltage, are you coupling the output with a large capacitor (e.g. about a 1,000µF) to block the DC?
If not, that's where the large load power is coming from.

 

The amplifier power supply in this thread is not a single +24V VCC. Instead it is a single +50V VCC.

 

The amplifier power supply in this thread is not a single +24V VCC. Instead it is a single +50V VCC.

Yes sorry, that’s what I had it at earlier. With the 50V supply here is what the sim showed,
as you can see the amp puts out peak 25W and the load puts out peak 52W, which would cause the circuit to destroy itself

 

as you can see the amp puts out peak 25W and the load puts out peak 52W, which would cause the circuit to destroy itself

No idea what you are trying to say here. Loads do not “put out” anything.

It’s like you are saying “I poured one liter of water into the bottle and then I took out 2 liters.”

I think you misunderstand what a speaker power rating means. If a speaker is rated at 25W, it means you can drive it with any amount of power up to 25W. Anything above that will cause severe distortion and eventually damage. But driving it with 10W is perfectly OK, it just will not be quite as loud.

 

Most people play an electric guitar at a very high output producing severe distortion.

Not true. The distortion is created in the preamp, not in the output stage. You can play a low volume with a lot of distortion or at a high volume with no distortion.

Guitar amps have two level controls, the gain control (preamp) controls the distortion and the volume control controls the output level.

 

The rock music show is lighted by the clipping indicators on the power amps.
A squarewave from the preamp sounds as bad as severely clipping from the power amp.

 

The rock music show is lighted by the clipping indicators on the power amps.
A squarewave from the preamp sounds as bad as severely clipping from the power amp.

That’s only when you turn it up to 11. When used as intended, the power amp should mot be clipping.

 

No idea what you are trying to say here. Loads do not “put out” anything.

It’s like you are saying “I poured one liter of water into the bottle and then I took out 2 liters.”

I think you misunderstand what a speaker power rating means. If a speaker is rated at 25W, it means you can drive it with any amount of power up to 25W. Anything above that will cause severe distortion and eventually damage. But driving it with 10W is perfectly OK, it just will not be quite as loud.

Yes I meant the speaker. 52W would blow it, which is why I was looking for help on how to solve this

 

My Radio Shack Minimus 7 speakers each have a label: 40W MAX. I fed them each 15W or less RMS maximum of audio with no DC.
A few years later, one woofer burned out and it and the identical replacement were marked: 5W KOREA.

Your LM1875 amplifier feeds up to 25W continuously into your 25W speaker but occasionally feeds 50W peak momentary pulses.
It takes a fair amount of continuous loud playing (heating) to blow out a speaker.
An amplifier clipping badly all the time produces double its low distortion output power because half of its output power is producing distortion.

 

If your 25W amp does not sound terribly distorted, it will not harm your 50W speaker. Stop worrying, and just don’t turn it up so loud it distorts.

 

52-Watts RMS, ( basically meaning "Average" Power ), "may" burn-up your Speaker's Voice-Coil.
But it might take an hour at this RMS-Power-Level to actually smoke the Speaker.
Random-"peaks" of ~100-Watts will probably not do any damage, even in the long term.

The Quality of the Speaker, and the reputation of the manufacturer,
will determine whether or not You can actually believe the stated Power-Rating.
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If your 25W amp does not sound terribly distorted, it will not harm your 50W speaker. Stop worrying, and just don’t turn it up so loud it distorts.

It’s a 25W speaker not a 50W, but either way, we will not be using at full volume so I should be good there. I did want to know a good way to dissipate heat on the amp chip itself? It’s extremely, extremely hot even when idle.

 

I did want to know a good way to dissipate heat on the amp chip itself? It’s extremely, extremely hot even when idle.

The datasheet for the LM1875 shows a typical idle current of only 70mA and with a 50V supply heats with only 3.5W.
Heatsinks are rated at a certain power at a safe temperature. Your IC heats to 20W when playing a 25W continuous RMS output.
Get and mount a 20W heatsink. The heatsink must not be enclosed.

 

Here's a stout Cast-Aluminum-Box that will make a fine Heat-Sink .........
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