Mack Gem sound clips

[amphead]

If you dig a little deeper into Robert's Mack link, the specs say it will handle 4, 8 or 16 ohms w/o damage to speaker(s) or amp...

Although all Mack amps are nominally rated for 8 ohm speaker cabs, 4 or 16 ohm cabs can be used without damage.

There has been a lot written about mismatching amp output and speaker cab impedances. Much of it warns about damage to the amp if a mismatch occurs.

Theoretically, damage can result due to an over-voltage or over-current situation depending on if the speaker cab impedance is higher or lower than the amp's output imedance.

However, running the numbers reveals that low-power amps - say, below 100 watts - should not experience any problems with output impedance mis-matches, assuming that the output transformer is of reasonable quality. The voltage or current change resulting from halving or doubling the speaker impedance vs. the output impedance simply does not push the tubes or output transformer into the danger zone.

Leaving theory behind, we have tested our standard amps in the worst conditions - a dead short across the amp's speaker output and an 'open circuit' meaning we ran the amp with no speaker plugged in.

The measured voltage and current data shows that the amps could run indefinitely without damaging the tubes or transformers.

Therefore, plugging in a 4 or 16 ohm cabs will never result in damage to the amp. The power output of the amp changes a bit and you can actually hear a change in tone, but there will be ZERO damage done to a Mack amp.

The Gem, being a VERY low power amp, is equally impervious to impedance mis-matches.

So, I can confirm that Mack amps do not have any problem at all with plugging in different speaker cabinets. Experiment to your heart's content!

Note that since I have only conducted the above testing on our own amps, I can technically only vouch for them. However, as I mentioned earlier, calculations show that other lower-powered amps with good iron should perform similarly.

Hope that wasn't too long winded and I hope that helps clarify our position on impedance matching!

[bigG]

Thanks, Don! Not being very tech-minded, that was a great explanation. Much appreciated!