Thread: will a 700watt 2 channel amp be ok for

Not that I've read the patent, but that sounds like an SMPS.
SMPS are "constant power" (output) - it was one of their main intentions (aside from removing the low-Hz transformers for efficiency, weight, and international AC inputs).


Battery and related specs have been catering for them for years (since 1990 if not before), hence the typical resistive, constant current, and constant power discharge curves and respective reserve times that are furnished.


It sounds like RIPS is merely a development of SMPS.
[ Not all SMPS are constant power, but since they usually monitor output voltage - as in amps and PC supplies etc - they are constant power output devices. Essentially constant power input too depending on higher current etc losses. ]

So why do many SMPS-containing amplifiers vary output power as if they are resistive?
Me smells some flawed marketing, else VERY strange designs.
(Imagine the M-series etc converters varying output (voltage) with input voltage!)
To quote Stargate's Teal'c "Stange indeed!"

for subs you might be better off with a monoblock amp. They tend to be higher power for your money and you don't need many of the features found on multi-channel amps. Especially since the subs should be running the exact same channel anyway.

(crutchfield used as reference point, I know they aren't the best prices)
Infinity kappa One $290 - 800x1
Kenwood KAC-9105D $300 - 900x1
Alpine MRP-M1000 $330 - 1000x1
Boston Acoustics GTA-1000M $350 - 1000x1
Rockford Fosgate Prime R1000-1D $350 - 1000x1
Alpine MRX-M100 $400 - 1000x1

2 channel amps:
actually I couldn't find any 400x2 2ch amps on that site...

4 channel amps, bridged:
Rockford Fosgate Power T1000-4AD $1000 - 500x2
there was a Focal amp listed for $1200 that did 380x2, but that RF amp was the only multi-ch amp that meets the rms on a pair of 400w subs

if you already own that 700w amp, then just get lower RMS subs... it depends on what you haven't purchased yet, I guess

Originally Posted by OldSpark

Alas a common misconception and quote, but totally false. It's like saying that computer memory is wasted because it only uses one byte or word (at a time).

The correct statement is that we use ALL our brain, but only 10% at a time. (ie - average instantaneous brain utilisation is 10%)
The becomes evident if you have seen enough brain activity mappings etc.



Too late to nip that one in the bud (like the flat earth crap), but I do try to dispel such myths.


PS - not that I used any analogies in my previous reply(s).

i stand corrected.. lol

Originally Posted by OldSpark

Not that I've read the patent, but that sounds like an SMPS.
SMPS are "constant power" (output) - it was one of their main intentions (aside from removing the low-Hz transformers for efficiency, weight, and international AC inputs).


Battery and related specs have been catering for them for years (since 1990 if not before), hence the typical resistive, constant current, and constant power discharge curves and respective reserve times that are furnished.


It sounds like RIPS is merely a development of SMPS.
[ Not all SMPS are constant power, but since they usually monitor output voltage - as in amps and PC supplies etc - they are constant power output devices. Essentially constant power input too depending on higher current etc losses. ]

So why do many SMPS-containing amplifiers vary output power as if they are resistive?
Me smells some flawed marketing, else VERY strange designs.
(Imagine the M-series etc converters varying output (voltage) with input voltage!)
To quote Stargate's Teal'c "Stange indeed!"

many amp designs still do not use the regulated design. after my recent power regulation adventures in my car (powering some recently-installed led tail lights), i agree that it is way to easy to not be included in all automotive devices.

i started looking into this--

according to crutchfield.com, they don't even mention the regulated power input on these models:
http://www.crutchfield.com/s_136HD60...Brand|JL+Audio

it is kinda visible in the cryptic product specs on jl's site(last sections under the notes):
http://mobile.jlaudio.com/products_amps.php?amp_id=482

after some searches focusing on the r.i.p.s. system, i found this on crutchfields site(link):

Originally Posted by crutchfield

R.I.P.S.(Regulated, Intelligent Power Supply): R.I.P.S. stands for "Regulated, Intelligent Power Supply" and is a central feature of the JL Audio's Slash v2 amplifier. The JL Audio R.I.P.S. System ensures consistent power delivery over a wide range of battery voltages and load impedances. This technology provides optimum power at any impedance level between 1.5 ohm to 4 ohm per channel and at any vehicle voltage level between 11V and 14.5V.

* Regulated Power Supply: "Regulated" means that the power supply adjusts its operation so as to maintain the amplifier's rated power output and low distortion operation over a wide range of vehicle voltages (11V-14.5 V). This allows the JL Audio Slash v2 amplifier's the rail voltage and clean power output to remain stable in real-world car-audio systems, resulting in superior fidelity and stability.
* Intelligent Power Supply: The "Intelligent" portion of the R.I.P.S. System is a circuit that actually monitors output current to optimize the amplifier's output power over a wide range of load impedances (1.5 ohm to 4 ohm per channel). The R.I.P.S. System detects the actual impedance being driven and adjusts output rail voltages to deliver optimum output. The entire process is seamless, automatic, and results in incredible dynamics for satellite channels and consistent power output for a wide range of subwoofer configurations. It also takes into account the real impedance of your car-audio system, rather than relying on often inaccurate assumptions based on a speaker's rated impedance.

and another dumbed-down version on jl's site:
http://mobile.jlaudio.com/products_a...hp?page_id=252


so yes, it i believe it is a SMPS power system, but they don't advertise it that way...


moving over to alpines lineup, i cannot find any info of the pdx series using this tech.
the pdx series uses a power management processor to reduce output when the amp starts to heat up, but i see no mention of a variable input power supply...

Very strange - an SMPS not based on a voltage regulated output....

That's not a dig at you soundman, but just an in MY experience statement. Plus an expectation that I will find you are correct, and that "car audio" has yet again done something strange & IMO illogical. (In this case I suspect a situation where they have the answer and are using the correct hardware, but in some strange and probably more complicated (and inferior) fashion! Not that that is unique to that industry!)

The only reason I'd see for that is to support their sales or kickbacks from the power side - ie, the items and expense required to prevent voltage sags. As most know, that's a big and lucrative market (which would be virtually eliminated with simple audio-amp "power splitting" topology).


But I'll have to defer till later when I will check your links. (yet again, Thanks!)
And I still have the Kicker PCB so I'll attempt to trace out its feedback circuit. But it should simply be voltage divider (resistive) from the PSU output, unless maybe with some amp final-driver overload or heat inclusion (ie, drop the output voltage).