@atmasphere correct! :-) Testing amp “effective” current range is not trivia, and it is beyond what is discussed in AG! my post was a simplest debug approach to check for major amp-spkr issues, before starting to randomly change components!
Question about high current amps versus "not high current amps"
Recently I read a reply to a post about a certain speaker, and the person who replied typed that (and I am going to paraphrase somewhat) the speaker required a high current amp to perform well and it wasn’t the WPC that was important.
Sorry as I am afraid that these are probably going to be "audio electrical questions for dummies," but here goes:
I vaguely remember being taught the PIE formula, so I looked it up online for a quick review and if I am understanding it correctly,
P (power/watts) = I (current/amps) x E (electromotive force/voltage) .
My first question would be: if I am understanding that correctly, how can wpc NOT matter since watts are the sum of current x voltage? I mean if you have so many WPC, don’t you then HAVE to have so much current?
My next question would be, if I am understanding PIE correctly, is E/voltage going to be a fixed 110 vac out of the wall, or is that number (E) determined by the transformer (so it would vary by manufacturer) and it is that (different transformers that are used in different amps) going to be the difference between a high and a lower current amp?
Or am I completely off base thinking that P is wpc and P is actually the spec in my owners manual that lists "power consumption as 420 watts operate 10 watts stand by"?
And lastly, what would be an example of a high current amp and what would be an example of a low current amp?
Thanks.
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As others have pointed out, if the amplifier in question doubles output power with each halving of impedance, it's a strong sign that it's a high current amplifier. Some manufacturers will claim a max current spec, for example, the venerable Adcom 555 series claimed (IIRC) 30 amps. With 8 output devices per channel in push pull, the summed current rating of 15 amps each makes that claim very plausible. An amp I like even better, the much maligned HK Signature 1.5, has 12 output devices per channel, also 15 amp devices, yet the manual claims 130 amps of current. This may be marketingspeak, as they don't mention whether it's per channel or both combined. In any case, it seems that a combination of output devices and their summed current rating, along with the stored energy in the power supply capacitors, would be the secret to how much current can be sustained for a period of time. It's definitely a topic I'd like to know more about as well. |
@dlevi67 that was a good summary from an engineering perspective, and a good introduction to Ohm's Law, which is exactly how I learned from other engineers (fellows) when first designing amps and speaker systems as a hobbyist. The others came in nicely with the nuances regarding load, sensitivity, etc |
Given the same 100 RMS 8 Ohm amp/circuitry, but one power supply with 1000 micro F and the other with 100,000 micro F. Speaker has an impedance dip to 2 ohm at 100 Hz. Can the 100k cap amp not provide a LOT more amps (for 1 millisecond) than the 1k cap amp? Isn't that were the "100 Watt RMS, 200 Watt PEAK" nomenclature comes into the picture? |
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