Amplifier reserve capacitance

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InterMechanico

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This will sound silly, but I'd like to know how my capacitance stacks up. My integrated amplifier has (4) 22,000 uf capacitors. In other words, 88,000 microfarads of reserve capacitance. What significance does this have?

Thanks.
 
A lot less significance than some would have you believe. Read Doug Self or Bob Cordell designing power supplies.
 
This will sound silly, but I'd like to know how my capacitance stacks up. My integrated amplifier has (4) 22,000 uf capacitors. In other words, 88,000 microfarads of reserve capacitance. What significance does this have?

Thanks.

I agree, sounds silly :)
 
Well here goes...

The obvious benefit is having storage for dynamic peaks. 88K is decent, and adequate for a general amp, but it's not a huge number. I had a threshold amp with about 200K uf of storage. You bet there was a difference in headroom during loud passages.

Companies like Mccormack use 1 small cap per output device, not a group for the collective amp.

Car amps that do not have this capacitive storage run out of headroom easily.
 
Capacitance as a number is pretty meaningless without some other reference. ARC for example is giving energy stored as joules.
 
Well here goes...

The obvious benefit is having storage for dynamic peaks. 88K is decent, and adequate for a general amp, but it's not a huge number. I had a threshold amp with about 200K uf of storage. You bet there was a difference in headroom during loud passages.

Companies like Mccormack use 1 small cap per output device, not a group for the collective amp.

Car amps that do not have this capacitive storage run out of headroom easily.

I wonder if "headroom" has more to do with the size of the power supply than the size of the capacitors? I've read that 1 Farad is equal to 1 Coulomb which is 1 Ampere for 1 Second. In other words, an amplifier with 200,000 uf reserve capacitance would have on reserve only 0.2 amperes for 1 second, or any combination thereof. Not a lot, or maybe that is a lot...

So, the reason I'm asking, is the Odyssey Stratos that I'm contemplating as second for a Bi-Amp Configuration has the option to increase the capacitance from 60,000 uf to 120,000 or even 180,000. The 180,000 uf version has a second transformer in it. The options aren't expensive, but I'm the kind of guy who is, as we speak, using a bottle of Bordeaux for a TT Clamp (works well, BTW), and likes to buy options that improve the quality of sound reproduction.
 
An amp is only as good as it's parts. I think of an amp as an entire powertrain, not just caps and toroids. It is better to have more robust parts with a proper transfer function.
I had an amp hotrodded by the manufacturer (Passlabs) and the increase of 100uf over stock resulted in more effortless peaks. I say this was most noticeable during large scale orchestral works that have a good dynamic range. BUT...the amp was already well designed and could handle tough loads like stats, planars and B&W easily.
 
I believe there is something to it. One of the things that drew me to my new AURALiC Merak amps was the dynamic headroom they exhibited. They have 112,000 uF of storage capable of delivering 120 Joules on demand. This translates to approximately 16 amps or almost 900 peak watts. Headroom is not an issue with them what so ever.
 
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Energy is what is required to make a speaker move and capacitance with voltage is what makes energy storage. So amplifier with 100.000uF/100V has more energy stored than amplifier with 100.000uF/60V.
My almost vintage ARC amp has 674 joules per specification. But even energy storage is pretty meaningless without output capacity, think about output impedance...
 
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