A true work of art for sale

[spkrman]

is there a particular reason those amps cost so much?

[Ryan from Ohio]

Arguably the best amplifiers ever made period. They may not have the bells and whistles of todays amps, but for brute clean power they will dominate.

Still worth the asking price without question!

[GlassWolf]

well, the A1200.1 retailed new for $1,299 in 1993-1996. This isn't unreasonable for a high end Class A/B amplifier that puts out 1200 watts RMS.
For one thing, you would never find any TL07x operational amplifiers in any ART series or Powerclass amplifier designs or their signal processors. They have a very high noise floor and their use often times makes an amplifiers output sound like "music being pushed through sand". The original designs preferred National SC LM series of OPAMPs. Better yet, Burr-Brown were sometimes seen in certain designs. Capacitors in or around the signal paths were always Poly Film, Mylar or Silver Mica. No crappy ceramics or high drift mono's were used. I am speaking of the PPI lineage prior to
being produced offshore. PPI designs also had a penchent for using high grade output devices such as those from ROHM and SANKEN. These were indeed audio grade output devices. If DEI's PPI amplifiers are at least using ON SEMI's MJx21193/21194 than I will concede this point. They really are great devices.

2N6488 and 2N6491 devices are BJT's. MOSFETS are used in power supplies as they are easier to control for high current switching and BJT's are used in output sections mostly due to PNP/NPN complementary pair parameter symmetry. It is also said that BJT's make for "smoother" sound than MOSFET's. Both PPI and Orion used these devices early on and possibly currently. They are good devices. Rated at 80V@15A
( not continuous ). They were once equally well at home in the power supply section as well as output sections as long as the rail voltages of the outputs were less than +/-40V. Fairchild makes good stuff, but the internal die size of many of their devices is smaller than their counterparts. Means, they are not as good at handling heat.

It is not a conicidence that these amplifiers are almost exactly designed the same from a circuitry standpoint. All 3 use the same output FETs which are Motorola Semiconductor (2N6488 and 2N6491) (M) and either Fairchild or International Semiconductor on the power supplies. (F) (I~R). All cream of the crop as far as High Tolerance MOSFETs, FETs, or JFETs.

Not to mention, the ART series amplifiers are just sexy as all Hell.

[J.W.]

that was awesome. i didnt understand half the words you just wrote kiki. all my brain took from that was "old PPI amps are good." :) lol.

[spkrman]

so in other words

it "sounds better" because you pay more

seriously... .5 distortion and .000000000005 distortion... lol how can you even tell???

So long as you have proper headroom, you'll never know the difference between 2 amps that are setup exactly the same.

Phsycoacoustics is fun... kinda like when you just spent 500 bux to lose 3db, but you swear it sounds better and louder

[Ryan from Ohio]

"Better by design"

Its not a matter of distortion rate.

Take say a Kenwood amp, then compare it to an equal sized ARC amp.

Enough said

The difference is like night and day, for whatever the reasons may be. It is what it is, thats all I know

[GlassWolf]

seriously... .5 distortion and .000000000005 distortion... lol how can you even tell???

Back in the old days (1982) It was FTC mandated for the manufacturer to provide a comprehensive single criteria power specification. However, with the de-regulation craze of the 80's, this requirement was dropped. This left it up to manufacturers to determine how to advertise and display their product specifications with no commonly accepted standard for emasurement.
I'll attempt to explain how THD is measured.

Of a signal, the ratio of (a) the sum of the powers of all harmonic frequencies above the fundamental frequency to (b) the power of the fundamental frequency.

The THD is usually expressed in percent as distortion factor or in dB as distortion attenuation.

Measurements for calculating the THD are made at the output of a device under specified conditions.

Now, there are several ways to measure THD that are commonly used. One is defined by the FCC, and another by the EIA.

Years ago a number of papers were written on human hearing and harmonic distortion. What they found was that the human ear is very insensitive to harmonic distortion that is close to the main signal, and increases in sensitivity to harmonic distortion further away from the main signal. The second harmonic, which is an octave away from the main signal, is the hardest to hear, especially when you are driving a loudspeaker.
The best estimates that I can give you is that we can detect somewhere between 1% and 3% of second order harmonic distortion. Which is why you can't hear it. If the sum total distortions were farther away from the main signal you would be able to hear it. Some solid state designs can have pretty low distortion but they can get to be aggravating after awhile. That's because the distortion generated by the amp is further away from the main signal where the ear is more sensitive.

Without going into too much detail, there are many factors in how THD can be measured, including but not limited to:
is the signal being used to measure THD a notch frequency, of full 20Hz-20KHz at equal power?
Over what unit period of time is THD being measured?
What kind of signal is being used to measure the distortion?
Point being, very few manufacturers specify this data, so THD is helpful at times, but again, not something to base a purchase on.
Remember, some of the best amplifiers in the world have an advertised THD of between 1% to 10%.
It's commonly agreed that distortion below 1% is inaudible, and in a car, below 10% is inaudible to the human ear.

There are two widely accepted ways of measuring THD. One is mandated by the FCC, and is the best way to measure distortion for car audio amplifiers. The other method is defined by the EIA and is far less acceptable for accurate audio amplifier comparisons.

So long as you have proper headroom, you'll never know the difference between 2 amps that are setup exactly the same.

Not always the case. A class D amplifier for example, spikes drastically in distortion levels as you approach peak output for the amplifier. This is a trait Class A and A/B amplifiers don't suffer to such an exaggerated extent. A class D amplifier also has such a poor switching speed and design that anything reproduced above the first three octaves or so will be so distorted as to be unusable by most people for audio purposes.
That aside however,there is a lot more to an amplifier than a single spec such as THD+N. Reliability and logevity are characterized in amplifiers of higher quality, as are tighter tolerances and superior designs resulting in a more stable power supply that, as you noted, will provide much better headroom, and a more efficient end result product.
If you really want to know what makes a good amplifier, read the FAQ section on amplifier basics. This one:
http://www.wickedcases.com/caraudio/amplifiers.html

Sounding louder is objective and easily judged. Sounding better is entirely subjective to a point, but improvements in factors like damping, driver control, and response curve are very audible many times with very simple changes to a system. What that's worth to you however, is entirely up to you and you alone.

If you think an Alphasonik or BOSS amplifier is just as good as a PPI Art series or Orion SX amplifier though, you're welcome to stick with those, but as it is said, a chain is only as strong as it's weakest link, and I'd rather have a strong system throughout, that I have faith in, to know I'm going to have a good end result. If you skimp, it'll show up at some point, and cost you more than you initially saved more times than not.

At laest I offered very objective reasoning for the cost of the PPI amplifier. Good internals for an amplifier of that size aren't cheap, even today. If you don't think a 1200 watt class AB amp is worth $600, that's your call, but none of your arguments really have much foundation, or much accuracy. Your post struck me as someone trying to rationalize having cheap equipment by just baselessly bashing something that's built extremely well from the ground up. The founders of Orion started as RF engineers. The founders of PPI were from the original PPI group. Considering those three companies reigned supreme for over a decade in the car audio world with nobody able to make products that could come close to their performance in that era for a similar price, they must have done something right.
The entire reason PPI was formed was due to a strife between the engineers in Orion over power supply topologies. Orion stuck to unregulated or loosely regulated fixed duty cycle power supplies, and PPI, as the name implies, went with a PWM regulated power supply with a variable duty cycle, which although is fairly common now in more expensive amplifiers thanks to SMT being prevalent now, was unheard of in the car audio world back in 1988. Using a power supply and internal components of this caliber at the time was groundbreaking, and state of the art, as their motto said.
"Precision Power - Absolutely state of the art."

[GlassWolf]

btw, nothing personal. sorry if that came across as mean at all. I respect the fact that a lot of people don't think older stuff is that good, or better than what we have today. I was simply trying to explain the reason for the cost, reflecting the cost to build those amplifiers.

[J.W.]

what i took from that post, besides "old PPI amps are good" :) is that not only will that amp sound amazing, but it'll probably last longer than most vehicles it's put into.

[Fishy]

is there a particular reason those amps cost so much?

What Kiki said.



Plus in 1990 power was just plain expensive. Even 400 watts was BIG back then. Heck, I think a Punch 150 went for three or four hundred bucks and the very first Punch 40(1983?) was around $200.

-Fishy