Need understanding on amperage

To clarify: The 60 amps figure of the amplifier is not how much current the amp can produce driving the speaker. If it were, we could apply the power formula, which is that Power equals the current squared times the resistance of the load.

So if we give the amp the benefit of the doubt and use a 1 ohm load, that means that the power output of the amp is 60 amps squared; 3600 watts! Obviously the amp can't do that, what this 60 amp number represents is how much current is produced when the power supplies are shorted out for 10 milliseconds, something that you would never, ever want to do!

So this has little to do with whether the amp can make a lot of 'current' when driving low impedance loads. I know of several tube amps that don't make nearly the same power than tout the same figure.

Seriously, is anyone suggesting that the output section of this amplifier can deliver 3600 watts even briefly?? The output devices would be destroyed. Now if you assume a 4 ohm load rather than 1 ohm, the power is then 14,400 watts. Obviously this 60 amp figure has to do with something else- the math isn't lying...

This rating has nothing to do with the output power of the amp. It does get conflated that way quite often though and I think a lot of manufacturers like it that way.

Tonywinsc, that music has such transients and that a stereo needs either very high power and/or efficient speakers to reproduce those transients is not a matter of debate.

What is a matter of debate is the math. Its more than just the current rating of the output devices; if you are really drawing 60 amps from the output section its pretty safe to say that the power supply voltage will be near zero as the amplifier is not capable of 14,000 watts (4 ohms) or 3600 into one ohm. In fact in this case the specs show that from 8 ohms to 4 this amp does not double its power, so we can see that there is a current limit somewhere (likely the power transformer). So the 60 amps will not be coming through the speaker terminals. Its a measure of the storage in the supply and when you look at the brochures this is confirmed. Its got a lot of storage, 100,000 uf. That is all the 60 amp figure is stating.

We make a tube amp that can do the same thing. In fact its rated at 80 amps because it has more storage than this transistor amp does! But in both cases all that current is not available to the speaker, if it were such amps would have a bad reputation with speaker manufacturers :)

The extra energy storage does however help with authority and smoother delivery at high power levels as there is less noise in the power supplies and so less intermodulation distortion. But it has no bearing at all on the amp's ability to drive 'difficult' loads. If you look at inexpensive SS amps of similar power, they have similar specs and ability to drive difficult loads; the difference is they likely don't sound as good doing it. **That** is the difference between the men and the boys, and why we pay the extra dollars.

Dhl93449, your math looks right but your conclusion doesn't. At the end of 10mS the supply voltage is only 24V so the current would be 24 amps- only 576 watts. The fuse would go a little longer and the 3600 watt figure would go much shorter or am I missing something?

Right! Now this is just my feeling about the matter, but I don't think the 60 amp rating is realistic if it means that the amplifier could be damaged or the like in the process. At that point we are clearly operating outside of the linear region of the amp- and such an amp is intended for music not square waves.

Bombaywalla, its not a given that the caps would be charging if the window is 10mS. A lot would have to do with where the AC waveform was at the time of the 'event' :)

BTW thanks to all that have contributed here.

Philipwu, to drive a 1 ohm load is a difficult task for any amplifier.

You might want to consider that if the load is difficult to drive, the amp will not sound its best! This is true of all amplifiers.

For tube amps this requires a special transformer to allow it to happen and you will find such a transformer to be very rare. While some transistor amps can actually drive a one ohm load, in general they would be better off using some sort of matching transformer as well.

IOW, a one-ohm speaker is impractical and should be avoided, as there are no amplifiers that can really sound like music playing such a load. As the saying goes, why go where angels fear to tread?

Hi Phil, if by momentarily, you mean only at one frequency, then things can be a lot different, depending on the frequency. For example, a lot of ESLs have impedances like that at high frequencies where no power is required. Despite that, many tube amps can often drive that just fine.

Thanks for the question. The Caddock volume control makes the MP-1 a little more transparent. Of all the options we offer, it is both most expensive and the least sonic effect. FWIW the new volume control on the Mk3.2 preamps in stock form is more transparent than Caddock controls of the older versions.