Pro Amps I.e. Crown, Qsc

[E-Stat]

I am yet to see too many home amps that have a supply as big as a Macro Tech 10000 (any amp with two power cords is cool), or even that a 5000 oh and lets not forget about the huge supply in the QSC RMX 5050. I do miss the days of my Macro Techs but I managed to get more power and lost about 300 pounds off my racks by going with Itech's

What is the capacity of either amp in joules?

rw

[kexodusc]

What is the capacity of either amp in joules?

rw

Curious, I can't figure out where you're going with this question...but I'd love to know.

[pelly3s]

im in the same boat.

i would love to see any hifi amp come close to the power and current of the MA-10000. The thing was used to power MRI machines. Its completely stable all day long at .5 ohms

[E-Stat]

Curious, I can't figure out where you're going with this question...but I'd love to know.

That would be quantifying the notion of "huge supply". As a point of reference, my mono amps store 250 joules each.

rw

[kexodusc]

That would be quantifying the notion of "huge supply". As a point of reference, my mono amps store 250 joules each.

rw

I'm missing something here, been a few years since my last physics class. But the relevant unit of application (power) is still watts, no? Regardless of joules.
With a unit of time introduced, wouldn't the number of joules and watts be the same anyway? Ie: 1 joule = 1 watt-sec?

(as I said, I'm very curious were you're going with this)

[E-Stat]

I'm missing something here, been a few years since my last physics class. But the relevant unit of application (power) is still watts, no? Regardless of joules.
With a unit of time introduced, wouldn't the number of joules and watts be the same anyway? Ie: 1 joule = 1 watt-sec?

There is no direct relationship with the quantity of watts from an audio amplifier and the stiffness of its power supply. They vary widely indeed. The formula for stored energy is J=CV2 /2 where Joules = Capacitance X Voltage (rail) squared divided by 2. (Sorry I can't get the HTML superscript tag to work). Do the math on some amps you know. Rated wattage is irrelevant. I know of some 100 watt amplfiers with stiffer power supplies than most 500 watt amps.

I liken power supply stiffness to torque. How quickly can you deliver those watts? For most sound reinforcement applications, the question is moot. There is no dynamic range to speak of. While the amps may be cranking out kilowatts, they lack the ability to dynamically jump like the best amplifiers are capable of. It took me years to fully understand what reviewers meant by an amplifier having "authority". It is that utter sense of control and ease at any power level with the ability to literally startle you on wide dynamic range material. As in truly live, unamplified music.

Quality and quantity are not the same.

rw

[kexodusc]

There is no direct relationship with the quantity of watts from an audio amplifier and the stiffness of its power supply. They vary widely indeed. The formula for stored energy is J=CV2 /2 where Joules = Capacitance X Voltage (rail) squared divided by 2. (Sorry I can't get the HTML superscript tag to work). Do the math on some amps you know. Rated wattage is irrelevant. I know of some 100 watt amplfiers with stiffer power supplies than most 500 watt amps.

I liken power supply stiffness to torque. How quickly can you deliver those watts? For most sound reinforcement applications, the question is moot. There is no dynamic range to speak of. While the amps may be cranking out kilowatts, they lack the ability to dynamically jump like the best amplifiers are capable of. It took me years to fully understand what reviewers meant by an amplifier having "authority". It is that utter sense of control and ease at any power level with the ability to literally startle you on wide dynamic range material. As in truly live, unamplified music.

Quality and quantity are not the same.

rw

I'm afraid my experience with pro-amps is far different than yours. If anything I find them every bit as dynamic, if not more than "audiophile" amplifiers. But to be fair, I I would suspect if you were to push a Bryston or Krell to their limits for sound reinforcement, they'd behave similarly. If you start to loose dynamics, that tells me you need a bigger amplifier. I'll admit I'm not an expert in this area though...I'll have to go crack open a physics textbook or two...as I said, it's been awhile for me.
I also don't understand your torque analogy. The "quick" element of delivering watts doesn't jive here. How long should it take? How long does it typically take? Is it really distinguishable?

Those kilowatt pro-amps do have fantastically huge power supplies. Larger than most big watt hi-end amps I'm aware of (though I expect there's some exception). I dunno...to me it seems pairing an amplifier with a PSU that can meet the expected demands placed on it with perhaps a bit of headroom would be sufficient. Beyond THAT, it becomes moot, with no additional advantage.

[E-Stat]

I'm afraid my experience with pro-amps is far different than yours. If anything I find them every bit as dynamic, if not more than "audiophile" amplifiers. But to be fair, I I would suspect if you were to push a Bryston or Krell to their limits for sound reinforcement, they'd behave similarly. If you start to loose dynamics, that tells me you need a bigger amplifier.

You're still talking in quantitative terms. I'm not talking about clipping characteristics.

The "quick" element of delivering watts doesn't jive here. How long should it take? How long does it typically take? Is it really distinguishable?

Play something with explosive dynamics like Orffs "Carmina Burana" or Stravinsky's "Rite of Spring" to illustrate my point.

Those kilowatt pro-amps do have fantastically huge power supplies. Larger than most big watt hi-end amps I'm aware of (though I expect there's some exception).

So, my question remains. You keep saying they're "fantastically huge". How huge? The metric for judging that parameter is joules. The big brother to my amps, the Siegfried, has 780 joules. The Passlabs X1000 has 700 joules. The Audio Research Ref 610T has 1000 joules. Crack open a case and look at the total capacitance and find out the rail voltage.
(edit) I couldn't find schematics for current Crown amps, but the CT800 amp with 305 watts /channel stereo runs 12,600 uf @ 87 volts. That yields 24 joules.

I dunno...to me it seems pairing an amplifier with a PSU that can meet the expected demands placed on it...

But most cannot on an instantaneous basis when the source material is wide range unamplified music. Here again, sound reinforcement applications are undemanding in that regard.

rw

[jneutron]

An interesting thread..what is a joule???

E-stat...everybody knows power cords don't make a difference..why do you continue to say this..just buy some (more) vanilla cords...


I would be concerned with several things with respect to the total energy storage of the supply bank..

1. How much droop occurs during heavy loads, and how this droop level makes it's way back into the electronics..output stage gain modulating (hfe vs Vce down neat Vce(sat), modulation of the damping factor in all four output quadrants.

2. How the input circuit re-charges this drain, both haversinewise and conductivity coupled cap draw back through the bridges.

3. For smps setups, are they two stage with PFC, or single stage..at least the PFC has spare energy to feed in during line zero crossings. (single phase systems).

4. The hf capacitance characteristics of the supply caps and loop coupling from the output draw back to the xfmr and out the line cord..geometry based, of course..a larger bank of capacitors makes the loop coupling less as a result of spreading the full current out among more spacial volume, thereby reducing the loop coupling to nearby circuits.

5. How inadequate the star grounding scheme is for large, hf current draws into low impedance loads.


Me, I just play with my rmx 1450..so far, it has served me well..but my applications have the amp over 35 feet from the front row of audience..about 100 feet from me (when I am hovering over the summer hired school kid who runs the sound and lights.) So I am unconcerned with fan noise.

Cheers, John

[E-Stat]

An interesting thread..what is a joule???

That reminds me of the classic line delivered by actor Fred Gwynne (Herman Munster) as judge in the movie "My Cousin Vinnie". After Joe Pesci as defense lawyer talks about "youths", Fred asks "What's a yute?"

A joule is a unit of energy or work named after nineteenth century physicist Jimmy Joule.

E-stat...everybody knows power cords don't make a difference..why do you continue to say this..just buy some (more) vanilla cords...

You know those crazy audiophiles and their shared mass hysteria.

I would be concerned with several things with respect to the total energy storage of the supply bank..

I'll leave the details to you. I just know I like 'em really big to provide better dynamics and slam. The two best sounding amps in my experience, the VTL Wotan and the ASR Emitter II Exclusive have such. The power supply of each mono Wotan stores 780 joules. While I'm not sure of the joule rating for the ASR, it possesses 1.2 farads of capacitance (400,000 uF of which is used in the battery supply for the input stage).

rw

[jneutron]

That reminds me of the classic line delivered by actor Fred Gwynne (Herman Munster) as judge in the movie "My Cousin Vinnie". After Joe Pesci as defense lawyer talks about "youths", Fred asks "What's a yute?"
rw

That was a good line..I really enjoyed Fred in that one..

A joule is a unit of energy or work named after nineteenth century physicist Jimmy Joule.
rw

I thought it was named after his brother "Crown"..or his father "Family".

We just shipped out a magnet for use in a facility on site, we had to test it and make it use less liquid, it stored 1.5 megajoules. But it was inductive storage, so didn't have the "slam" my 6 kiloamp diode pulser had..

You know those crazy audiophiles and their shared mass hysteria.
rw

Yah, we should take em out the back and shoot em..or at least make em listen to inna gadda da vita on headphones..

I'll leave the details to you. I just know I like 'em really big to provide better dynamics and slam. The two best sounding amps in my experience, the VTL Wotan and the ASR Emitter II Exclusive have such. The power supply of each mono Wotan stores 780 joules. While I'm not sure of the joule rating for the ASR, it possesses 1.2 farads of capacitance (400,000 uF of which is used in the battery supply for the input stage).

rw

Crazy audiophiles one and all..it'd be so much more elegant to pull the v feedback off the speaker terminals using a quadaxial setup of the type I had sent to Ted. Too bad he never returned them to me..

Oh well, live and learn..It'll be interesting to find my design on someone's product in the near future..with no credit for da tinkin part of it..

Man, I love this jpeg capability..nothin like a pic..here's that cap bank. uses copper buss cause it's 6 kiloamps. 32 capacitors, 2000 uf apiece, 400 volts give or take..5,120 joules..I'm glad I only deal with the small stuff, the big stuff scares me..

Cheers, John