QSC PL380 amp

vasyachkin

Disabled Account
2007-12-31 1:16 am
8000 watts for $2,700

QSC Powerlight 3 series

detailed power specs

PL380 animated flash tour (internal layout)

i think they done a great job undercutting the price of an I-Tech 8000

I-Tech of course wins hands down on features but to get the same power for less than half the price ... i say its not a bad deal :)

i think this PL380 may very well become the next amplifier i buy whenever i have the money ... it would then free my QSC PLX 2400 from subwoofer duty so i could use it on main speakers again ... i originally got the PLX 2400 for mains and it did a great job there but i had to switch it to subwoofer because it was the only thing i had big enough to handle the sub ...
 
You don't seem to understand class D. This amplifier can actually provide substantially more power than the class H models with less input current from the mains plug. This is particularly true when driving horn loaded bass systems whose impedance is highly reactive. 230V AC 10A is should be enough to drive such an aplifier into clipping with music. Anyway, the power supply would fold back if you attempted to draw substantially more current from mains in a sustained way.
 
Read the specs Eva - it in fact says Full power sine wave 100A - yeah burst only, still it's what it says.

I understand class-d and class-h, what I'm wondering is why QSC only makes their top powered amplifiers class-d? Why not also make lower powered models as class-d? Why do they continue to make their lower power models as class-h? They can get the same benefits of class-d even in lower output power/wattage amplifiers.
 

vasyachkin

Disabled Account
2007-12-31 1:16 am
well the circuit takes time to trip

you can experiment by running a microwave and a toaster at the same time ... and time how long it takes to trip

motors (vacuum cleaner etc) draw much larger current at spinup than during operation so the circuit breaker ideally should be designed to allow this burst of current for 2 or 3 seconds without tripping

just because the amp may from time to time pull 100A for one or two cycles not mean it would necessarily damage or trip a 20A circuit

as far as why they don't put class D on smaller amps - i think this may be their first class D amp. they most likely will eventually get around to putting class D into their other amps.

most likely the reason they use class H everywhere is because they simply know how to do it well and they have been follwoing the "if it ain't broke - dont fix it" rule up until now

why they started class D off with from the highest power end - probably because they already have a design that makes 4000W out of 2 rack units using class H but they did not have any 8000W designs, certainly not in 2 rack unit form factor. apparently based on success of I-Tech and Lab.Gruppen amps they decided it was time to step it up.
 

kASD

Member
2004-12-25 12:24 pm
N/A
See the output response of this pre-filter amp.......:bigeyes:

Peaking at HF with no load..........:bigeyes: :bigeyes:
 

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Genomerics

Disabled Account
2004-10-05 12:10 pm
Bwaaaaaaa Haaaaaaaa Haaaaaaa Haaaaaaaa.....

8000W 100A

Specmanship to the extreme.

Rule of thumb is 4A/mm^2. Look at the wire on the toroids in the input filter. Look at the transformer.... You get bigger ones in TV's.

Professional Audio........ Why not just dry up and blow away?

DNA
 

vasyachkin

Disabled Account
2007-12-31 1:16 am
Genomerics said:
Bwaaaaaaa Haaaaaaaa Haaaaaaa Haaaaaaaa.....

8000W 100A

Specmanship to the extreme.

Rule of thumb is 4A/mm^2. Look at the wire on the toroids in the input filter.

if you look at the specs more carefully you will notice that the power draw of this amp is 18A which is perfectly consistent with your 4A/mm^2 rule of thumb

Genomerics said:

Look at the transformer.... You get bigger ones in TV's.


this transformer operates at something like 100 KHZ, its part of a switch mode power supply. its as big as it needs to be.

8000W is music power, not sinewave power

everything is legit ... you can relax now
 

wg_ski

Member
2007-10-10 5:21 pm
vasyachkin said:
well the circuit takes time to trip

...
just because the amp may from time to time pull 100A for one or two cycles not mean it would necessarily damage or trip a 20A circuit


That 20A circuit could drop up to 3% at full load. Add an extension cord and drop some more. Every time the kick hits and the clip light comes on for more than 1/120th of a second you're gonna draw that 100 amps. Then the mains drop by 15%. It comes back up in between, but that's not when it's needed. So much for 8000 watts. Now you've got 6500. Full power is gonna take a dedicated circuit, overkill on the wiring, or both.
 

Genomerics

Disabled Account
2004-10-05 12:10 pm
vasyachkin said:


if you look at the specs more carefully you will notice that the power draw of this amp is 18A which is perfectly consistent with your 4A/mm^2 rule of thumb



this transformer operates at something like 100 KHZ, its part of a switch mode power supply. its as big as it needs to be.

8000W is music power, not sinewave power

everything is legit ... you can relax now

Ooooooh Switch Mode Power Supply. 100KHz..... We are not worthy....

The wire on those toroids still looks a bit thin but I suppose it is exposed so we might up the 4A/mm^2. Looks like the transformer might manage to be about ETD59 size so my telly jibe might have been misplaced.

So..... It's an 1800W for $2700 amplifier. :smash:

Thank you for your belated honesty.

DNA
 

wg_ski

Member
2007-10-10 5:21 pm
Par for the course

Genomerics said:


So..... It's an 1800W for $2700 amplifier. :smash:

Thank you for your belated honesty.

DNA

Don't go blaming it on this amplifier. They're ALL built/measured/spec'ed this way. Nominal operating condition is 1/8 power, pink noise, into nominal (not minimum) impedance. Class AB, H, D, you name it. The old CS800 could put out 800 watts sinewave from now till the power company turned your lights off but those days are gone. An 8000 watt amp built to run that way would add another zero behind the price tag and weigh 100 pounds - even with a SMPS.

Which is why I'm fed up with this stuff and build my own. I've gotten spoiled to the old school and wish they'd build amps with modern circuitry that had the same oomph as the stuff from the 80's. Modern amps are not *bad* - just not what they could be.
 

vasyachkin

Disabled Account
2007-12-31 1:16 am
Genomerics said:


Ooooooh Switch Mode Power Supply. 100KHz..... We are not worthy....

The wire on those toroids still looks a bit thin but I suppose it is exposed so we might up the 4A/mm^2. Looks like the transformer might manage to be about ETD59 size so my telly jibe might have been misplaced.

So..... It's an 1800W for $2700 amplifier. :smash:

Thank you for your belated honesty.

DNA

ok i finally understand what your problem is. i can only imagine you designing a fighter jet or an attack helicopter or something ... you would overbuild every part by a factor of 10 and the thing would be too heavy to take off.

believe it or not professional amplifiers actually are much more desirable when they are LIGHT AND SMALL which is of course exactly the opposite of what you prefer.

well then go ahead and build a 200 pound class A amplifier and brag that its 50 watt power rating is more "real" than another amp's 8000 watt power rating.

for a sound reinforcement application nobody would take your 200 pound class A amp even for free.

for your information the I-Tech amplifier is regarded as one of the best subwoofer amplifiers by pros in sound reinforcement and it only weighs 15% more than PL380.

i hope you enjoy listening to sinewaves ...
 

vasyachkin

Disabled Account
2007-12-31 1:16 am
TOINO said:


Very descriptive and scientific statement !...

Only data missing is� the kind of music ! :rolleyes:

it does not matter what kind.

it really does not.

NO MUSIC approaches the energy content of a sinewave. the best ( actually the worst ) any music can do is approach pink noise which is several Db less energy than a sinewave.

its not a sound engineering practice to design a product for an application other than the one it will actually be used for.

NOBODY BUYS AMPLIFIERS TO LISTEN TO SINE WAVES

a formula 1 car is not a farm tractor. and just because the tractor has more torque and longer mean time between failures does not make it a superior racing machine ...

i suppose a race car's engine horsepower is not real because you have to rebuild the engine after every race ... too bad thats exactly what its designed for. but, but ! but what if i want to use it to tow a trailer to florida ? TOO BAD

i see we have a lot of tractor fanatics here ...