nooby's dumb speaker question(s)

[BubbaWilsap]

I hope this simple question won't offend those more experienced than I.
I (think) I understand that speaker impedance can be construed as speaker resistance. So, I can understand why, as impedance is reduced, amplifier power appears to increase, and why too low an impendence will appear to the amp as a short, so that is to be avoided.

My questions in this regard are: if all I just assumed is true (correct), then:

1) Why do higher impedance speakers always seem to "get along" better with many amps, and
2) Why do tube, but not transistor amps, have multiple speaker impedance connections? Wouldn't this benefit transistor amps as well as valve circuits?

Thanks in advance for any feedback/advice.

 

[Another Johnson]

1. High impedance is a lower load. Low impedance is a higher load. High impedance demands less current, so easier on the amp.

2. Tube amps use transformers to couple to the load. So you choose the taps that best represent the load. Transistor amps couple directly without transformers. So you just “hook’m up.”

 

[Robh3606]

This will help

Heavy Load: How Loudspeakers Torture Amplifiers

Why, in loudspeaker reviews, is impedance measured (assuming that the magazine in question bothers to measure anything)? Generally, for one principal reason only: to establish whether the speaker presents an "easy" or a "difficult" load to its partnering amplifier. In the design context, much...

www.stereophile.com

Rob

 

[BubbaWilsap]

1. High impedance is a lower load. Low impedance is a higher load. High impedance demands less current, so easier on the amp.

2. Tube amps use transformers to couple to the load. So you choose the taps that best represent the load. Transistor amps couple directly without transformers. So you just “hook’m up.”

Thanks... I'm trying to get this straight. Can you define "load" in this context? Forgive my ignorance.

 

[Another Johnson]

Load is a measure of effort required to complete a task.

Ohm’s law says that Voltage is equal to Current times Impedance.

If the music is trying to present a Voltage of 4V at some frequency to the speakers, and the speakers have an impedance with magnitude of 2 Ohms at that frequency, the current required to get 4 volts across the speaker is 2amps. If it’s 16 Ohms, only a quarter of an amp is required.

The load is what you are trying to drive with the amp. It is easier to present 4V and 1/4 Amp across 16 Ohms than it is to present 4V and 2 amps across 2 Ohms.

Power is Voltage times Current. So in the 2 Ohm case, the power required is 8 Watts. In the 16 Ohm case, it is only 1 Watt.

Yet in both cases, you’re trying to get the speakers to present the same 4Volt musical signal.

All of this is further complicated by the fact that real impedances are not scalars, but phasers with both real and imaginary components.

if you’ve not taken an introductory EE class which included AC components, it may be a challenge to really grasp it.

 

[BubbaWilsap]

sounds like i need to spend a little time with ac component basics, thx for the tips