Regulated power supply

[Mitch86 5,000+ posts]

Why aren't there more amps with regulated power supplies, allowing for the same power at 1-4 ohm? The few out there are usually aren't very powerful either. Wouldn't it benefit a company like Sundown or others that are heavily used in competition to have an amp that did say, 2.5k+ @ 1-4ohm. Seems like it would do well since trying to keep rise at a minimum and getting the most power is huge in comps. Wire to 1 ohm, rise to 4 but still do the same power.

There is probably a reason this isn't a "norm"...I just thought about it.

Click to read more...

 

[big scott]

i to wish all amps were like that..

would now have to worry about rise..

not sure why that dont.

 

[trumpet 5,000+ posts]

A regulated amplifier power supply tries to maintain a steady output voltage. As the input supply voltage sags it will try to draw an increasing amount of current. As many of us know, it gets expensive to increase the current supply(high output alternator, large gauge wire, etc.).

 

[fly_marlin]

From Glasswolf's pages:

Regulated Power Supplies

Most early audio amplifiers contained unregulated power supplies. Regulated supplies require very high quality filter capacitors (called "low ESR" capacitors), output chokes, and an optically isolated voltage feedback circuit. Regulation occurs by controlling the switching pulse width from 0 - 100% to compensate for changes in the battery and rail voltage. The same action occurs when the audio level increases. As the amplifier draws more power from the supply, the rail voltage drops. Again, the regulator circuitry senses this drop and responds with an increased pulse width.

The high frequency PWM waveform is rectified (converted to DC) and applied to the output filter choke and capacitors. This output of this circuit is the + and - DC rails that feed the power amplifier.

Unregulated Power Supplies

Unregulated power supplies are less expensive than regulated supplies. They do not require an output choke, voltage sense or isolation circuitry. Because the duty cycle is nearly 100%, capacitor ripple current is much lower in unregulated supplies. Lower ripple current requires less expensive capacitors throughout.

Often we hear that unregulated designs have more "headroom". That means that the amplifier will produce extra power during transients. Most home audio amplifiers employ unregulated power supplies. The power supplies in these amplifiers run at 60 Hz, thus the filter capacitors must be 200-500 times larger than those used in high frequency switchers. The extra capacitance in home audio amplifiers results in extra headroom. Headroom for anything other than very short transients simply doesn't exist in the unregulated designs. The following is an example of specifications for an unregulated vs. regulated amplifiers.

Unregulated designs have a higher supply voltage at low power, causing higher voltage on the output transistors. This reduces the amplifier's efficiency.

Small amplifiers (less than 100 watts) cannot justify the extra cost of the regulation circuitry, so we often see unregulated supplies in these amplifiers.

Pros and Cons of Regulated / Unregulated Supplies

Some designers try to keep their supplies regulated down to battery voltages as low as 9.5 volts. The supply compensates by increasing the current. The current increases dramatically at the lower voltages. Because of higher currents at the lower voltages, the supply efficiency drops further, requiring even more current.

At higher voltages, the pulse width reduces, causing increased ripple current. This high current creates heat in the filter capacitors and can destroy the capacitor's electrolyte. Some manufacturers do not use capacitors of sufficient quality for this range of regulation. These amplifiers may not perform up to specification just one year after installation. Also, the extra current at low voltages is extra hard on a battery that is already suffering! So, I recommend that amplifiers stay in regulation down to about 11 - 11.5 volts. Any properly working charging system can easily keep the battery voltage well above this.

 

[Jeffdachef 5,000+ posts]

Considering how much current the bdcp and jl slash drains, your 400 amp hour battery bank and 350 amp alt may not even be to enough to run a 5k regulated amp

 

[Mitch86 5,000+ posts]

Makes sense I guess. I've never heard about them being current hogs, but I can see where it wouldn't be beneficial to have in a competition setting if they draw more.

I knew their had to be reasons for it not being more common, even for lower power amps.

 

[TaylorFade 10+ year member]

They're expensive and inefficient.

Exhibit A:

Rockford Fosgate T1500-1bdCP Power Series mono sub amplifier — 1,500 watts RMS x 1 at 2 ohms at Crutchfield.com

Exhibit B:

JL Audio HD Series HD1200/1 Mono subwoofer amplifier — 1,200 watts RMS x 1 at Crutchfield.com

 

[Mitch86 5,000+ posts]

They're expensive and inefficient.
Exhibit A:

Rockford Fosgate T1500-1bdCP Power Series mono sub amplifier — 1,500 watts RMS x 1 at 2 ohms at Crutchfield.com

Exhibit B:

JL Audio HD Series HD1200/1 Mono subwoofer amplifier — 1,200 watts RMS x 1 at Crutchfield.com

I knew they were expensive. Didn't think about efficiency. I ead just thinking that even if they were a little more expensive, they would be popular in comps because of the ability not to lose power to rise etc.

 

[Rich B 5,000+ posts]

Why aren't there more amps with regulated power supplies, allowing for the same power at 1-4 ohm? The few out there are usually aren't very powerful either. Wouldn't it benefit a company like Sundown or others that are heavily used in competition to have an amp that did say, 2.5k+ @ 1-4ohm. Seems like it would do well since trying to keep rise at a minimum and getting the most power is huge in comps. Wire to 1 ohm, rise to 4 but still do the same power.
There is probably a reason this isn't a "norm"...I just thought about it.

Phoenix Gold made a series called "Xenon" that was so tightly regulated it made the same power from 1ohm to 4ohms.

It was a hard sell, as people expect more power when they buy another sub, to make it louder.

Nice amps though.

 

[Mitch86 5,000+ posts]

Phoenix Gold made a series called "Xenon" that was so tightly regulated it made the same power from 1ohm to 4ohms.
It was a hard sell, as people expect more power when they buy another sub, to make it louder.

Nice amps though.

The Xenon line was the one I was thinking of when this crossed my mind actually. If I remember correctly, they weren't real pricey. Not JL pricey, anyway. I think the Xenon line went up to 1200 watts?

 

[n2audio 5,000+ posts]

From Glasswolf's pages:
Regulated Power Supplies ...

Unregulated Power Supplies ...

That information is talking about power supply operation.

Not output power vs load consistency like JL's RIPS.

They're expensive and inefficient.

Only if the charging system is weak.

 

[TaylorFade 10+ year member]

That information is talking about power supply operation.Not output power vs load consistency like JL's RIPS.

Only if the charging system is weak.

What does the charging system have to do with it?

 

[hispls 5,000+ posts]

Why aren't there more amps with regulated power supplies, allowing for the same power at 1-4 ohm? The few out there are usually aren't very powerful either. Wouldn't it benefit a company like Sundown or others that are heavily used in competition to have an amp that did say, 2.5k+ @ 1-4ohm. Seems like it would do well since trying to keep rise at a minimum and getting the most power is huge in comps. Wire to 1 ohm, rise to 4 but still do the same power.
There is probably a reason this isn't a "norm"...I just thought about it.

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.

 

[hispls 5,000+ posts]

They're expensive and inefficient.
Exhibit A:

Rockford Fosgate T1500-1bdCP Power Series mono sub amplifier — 1,500 watts RMS x 1 at 2 ohms at Crutchfield.com

Exhibit B:

JL Audio HD Series HD1200/1 Mono subwoofer amplifier — 1,200 watts RMS x 1 at Crutchfield.com

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.

 

[Boomin_tahoe 5,000+ posts]

So is that RF amp 1500 watts @ 1 ohm or 2 ohms?!

I spotted a typo on the crutchfield link above... @TaylorFade