Regulated power supply

[LosIsATool 5,000+ posts]

To me the RF CP amps seem to be just like a 1 ohm amp dropping to .5

Power goes up a bit but efficiency tanks

With CP going from 2ohm to 1 power goes up a bit and efficiency tanks.

My slash amps made a beautiful sound but efficiency was horrible, they pull current even when its not needed to maintain its power.

 

[Mitch86 5,000+ posts]

That's NOT what regulated power supply means. Zed has been building amps with regulated power supplies since the 80's that double power when you halve impedance.
These amps like JL should be considered an amp that makes 1000W @ 4 ohms but doesn't have a robust enough power supply to double power as you halve impedance so it limits output as you drop impedance.

As someone else posted, regulated power supply means that it'll make the same power at any input voltage... so between 11.5V and 14.8V (or whatever safe operating range is) you get the same power whereas unregulated amps make more power as you increase the charging system voltage (hence the popularity of 18V charging systems). Unregulated is a much cheaper way to build and much simpler from an engineering standpoint. It's also cheaper to use the input voltage for "free" output (for those who can keep high voltage) by going unregulated.... these whole same max power at 1 ohm or 4 ohm thing is a different animal from regulated power supply.

In short, say you want 1000W at 4 ohms, ONLY for the sake of having 1000W at 4 ohms, you're better off buying a Chinese/Korean "3500 @ 1 ohm" amp. Since you'll get the same thing at 4 ohm with the possibility of more if you go lower for about the same MSRP.

Maybe I'm using the wrong term... I'm referring to amps that do roughly the same power through a range of impedences 1-4 ohm for example.

I understand that they'd be expensive, but so is running 10k plus and only seeing part of that power most of the time.

 

[hispls 5,000+ posts]

To me the RF CP amps seem to be just like a 1 ohm amp dropping to .5Power goes up a bit but efficiency tanks

With CP going from 2ohm to 1 power goes up a bit and efficiency tanks.

My slash amps made a beautiful sound but efficiency was horrible, they pull current even when its not needed to maintain its power.

That's not necessarily inherent of a regulated power supply but some other part of their design philosophy which may or may not have a good reason. Those slash amps are good sounding and solid performers though, I've always liked the sound of the installs I've seen them in or done with them.

Maybe I'm using the wrong term... I'm referring to amps that do roughly the same power through a range of impedences 1-4 ohm for example.
I understand that they'd be expensive, but so is running 10k plus and only seeing part of that power most of the time.

The point being to make 10KW at 4 ohm you must design an amp to make 10KW at 4 ohm. Since a car amplifier tries to maintain constant voltage, by it's nature it will want to halve power as you double impedance and double power when it halves impedance. Making it put out the same power as you halve impedance is essentially just neutering the amp, or protecting it from blowing up because you haven't built it strong enough to really be stable into those lower loads.

 

[Mitch86 5,000+ posts]

That's not necessarily inherent of a regulated power supply but some other part of their design philosophy which may or may not have a good reason. Those slash amps are good sounding and solid performers though, I've always liked the sound of the installs I've seen them in or done with them.


The point being to make 10KW at 4 ohm you must design an amp to make 10KW at 4 ohm. Since a car amplifier tries to maintain constant voltage, by it's nature it will want to halve power as you double impedance and double power when it halves impedance. Making it put out the same power as you halve impedance is essentially just neutering the amp, or protecting it from blowing up because you haven't built it strong enough to really be stable into those lower loads.

I get what you're saying now and it makes sense. I wasn't necessarily talking about that high of power output. I meant like a 2500 where you could have multiples but achieve realistic power without worrying about rise in a competition setting. But, as you said, if its just as expensive or more so to make it do that power at 1-4ohm, you might as well get something that is going to do more power as you go down.

 

[TaylorFade 10+ year member]

Not sure where you get inefficient? Theoretically yes, but not by that much. My Minotaurs make around 50V into 1.4 ohm DCR and I rarely open 60A fuses on them. I have never opened an 80A fuse. Overall I'd say running these at 2 ohm I see far better efficiency than any Korean amp I've ever used @ .5 ohm.... though this is a bit anecdotal based on simply the reaction of system voltage.

Observation and conversations with amplifier engineers?

Perhaps "inefficient" was the wrong wording. Maybe... *less* efficient than unregulated?

 

[hispls 5,000+ posts]

Observation and conversations with amplifier engineers?

Yes to both. As you well know from your extensive testing, the "efficiency" numbers promised by many of these class D manufacturers rarely play out in the real world. AFAIK most are at 4 ohms and often at a frequency that most of us don't even play.

 

[n2audio 5,000+ posts]

The point being to make 10KW at 4 ohm you must design an amp to make 10KW at 4 ohm. Since a car amplifier tries to maintain constant voltage, by it's nature it will want to halve power as you double impedance and double power when it halves impedance. Making it put out the same power as you halve impedance is essentially just neutering the amp, or protecting it from blowing up because you haven't built it strong enough to really be stable into those lower loads.

You're looking at it like a brain dead novice.

The current demand that has to be accounted for in the design would be at 1.5 ohms. The RIPS (and similar) amps, unlike most, won't fall on their face as impedance increases. The amp takes a measurement when it powers up to set the rail voltage which is how it produces consistent power from 1.5-4.

It's not that those amps lack the balls to increase power as impedance drops, they possess the "intelligence" (rIps) to maintain it as impedance rises.

 

[LosIsATool 5,000+ posts]

You're looking at it like a brain dead novice.The current demand that has to be accounted for in the design would be at 1.5 ohms. The RIPS (and similar) amps, unlike most, won't fall on their face as impedance increases. The amp takes a measurement when it powers up to set the rail voltage which is how it produces consistent power from 1.5-4.

It's not that those amps lack the balls to increase power as impedance drops, they possess the "intelligence" (rIps) to maintain it as impedance rises.

Rips will still lose power as imp rises. Just not voltage drop which sets them apart.

 

[hispls 5,000+ posts]

You're looking at it like a brain dead novice.The current demand that has to be accounted for in the design would be at 1.5 ohms. The RIPS (and similar) amps, unlike most, won't fall on their face as impedance increases. The amp takes a measurement when it powers up to set the rail voltage which is how it produces consistent power from 1.5-4.

It's not that those amps lack the balls to increase power as impedance drops, they possess the "intelligence" (rIps) to maintain it as impedance rises.

That is NOT how they work and the VP of JL explains that the power supply does indeed limit the rail voltage so that it doesn't blow itself up at low impedance here:

How does RIPS (JL Audio) work? - Car Audio | DiyMobileAudio.com | Car Stereo Forum

A simple google search could have revealed this to you, but you just went and made something up then called me a "brain dead novice". I'll give you the benefit of the doubt and guess you're just drunk or something because you should know better.

 

[n2audio 5,000+ posts]

That is NOT how they work and the VP of JL explains that the power supply does indeed limit the rail voltage so that it doesn't blow itself up at low impedance here:
How does RIPS (JL Audio) work? - Car Audio | DiyMobileAudio.com | Car Stereo Forum

A simple google search could have revealed this to you, but you just went and made something up then called me a "brain dead novice". I'll give you the benefit of the doubt and guess you're just drunk or something because you should know better.

I didn't make anything up. I read that thread just recently, and have read several like it in the past. I've actually followed a lot of Manville's various forum contributions over the past several years. I just understand what he was talking about and you don't seem to.

RIPS doesn't limit the rail voltage to keep from "blowing up". It limits it because to drive low impedance loads it doesn't need high voltage, it needs high current.

I didn't call you a brain dead novice either. I said you were summarizing the amp like one.

 

[The_Quiet_One 10+ year member]

I've looked into the general workings of both RIPS and BDCP and as far as I know these 2 statements pretty much sum it up.

RIPS "locks" in to make rated power at the nominal impedance to which you're wired (if it's within 1.5-4 ohms).

BDCP tries to put out a bit more power than average across higher impedances.

- Now why don't manufacturers make the product your describing? If you ignored the engineering hurdles you still have a market who is still in a race to 0. There wouldn't be enough customer base to make it worthwhile.

 

[hispls 5,000+ posts]

The amp takes a measurement when it powers up to set the rail voltage

From Manville:

A) Amp turns on and wakes up in the 4 ohm setting (highest rail voltage)

B) If the user never turns it up loud and never clips the amp, it will stay in the high-voltage setting"

I didn't make anything up. I read that thread just recently, and have read several like it in the past. I've actually followed a lot of Manville's various forum contributions over the past several years. I just understand what he was talking about and you don't seem to.RIPS doesn't limit the rail voltage to keep from "blowing up". It limits it because to drive low impedance loads it doesn't need high voltage, it needs high current.

I didn't call you a brain dead novice either. I said you were summarizing the amp like one.

Manville also says: " the circuit has been tweaked to allow the amplifier to deliver the most rail voltage that is safe into a given load. "

Why would you call it "high current" at low impedance if the amp will be producing the SAME MAXIMUM CURRENT at each rail voltage "gear"? A high current amp does NOT need to drop down the rail voltage, it keeps it steady and just delivers more current (because it can).

Spin this however you like, but earlier in that post he explains how in early versions of that design with manual impedance switches people would simply switch to the high current setting, run low impedance and blow up amps because they cannot deliver that much current. He is indeed dancing around the fact that the amp lowers rail voltage not because you want the same power at 1.5 or 4 ohms, but because if it kept it's 4 ohm rail voltage into a 1.5 ohm load it would blow up.

He explains also (as I quoted above) that the amp powers up into 4 ohms and doesn't test the impedance of your load ever. It does not run a test on startup to decide which rail voltage to set as you claimed. He further explains that if you never drive the amp hard it will NEVER step down and lock into a lower rail voltage. Put this all together and you have an amp that is designed to make 500W into 4 ohms but without a big enough power supply to be stable down to 1 ohm so rail voltage is limited to protect the amp.

It boils down to semantics and design philosophy but perhaps you should re-read that thread. Or at least the first page worth of comments. OR if he claims elsewhere that the amp tests the load when you power up, or that it could safely produce more current than the rail voltage "steps" allow please point that out.