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A class D amplifier for example, spikes drastically in distortion levels as you approach peak output for the amplifier.

I just recently aquired a pair of Xtant 1.1i's which are Xtant's full range Class D mono offerings. I bought them for a midbass application, but was curious as to how they would sound full range. I hooked up one to the left side of my front stage(100x1@4ohms) and left the bridged output of my 4180c(180x1@4ohms) on the right and did a crude A/B comparison. Aside from an obvious difference in volume the 4180c was defintely the brighter of the two, but the 1.1i did sound very warm, possibly even "better" than the other. I thought I noticed some distortion in the upper frequencies at moderate volume with the 4180c that seemed absent with the class D, but this may have been due to a difference in frequency response or the fact that the 4180c was bridged. What I did notice when pushing it hard was that the 4180c gradually started to sound worse, but the distortion of the 1.1i was rather abrupt especially in the upper frequencies.

For the time being I plan on running my 6w0's off the 1.1i's at around 70-200 Hz, but since my new Clarion has 4 sets of preouts I may eventually try the "triamp" thing. I'll run my tweets off the 4180c(45x2), the mids off the 1.1i's(100x2) and the 6w0's off the 4180c at either 45x2 or 90x1.

I've never biamped a set of components before so am a bit hesitant and worried I'll toast my tweets w/o the benefit of a passive xover. I know my Q's existing passive xover is pretty inefficient and am hoping that the increased efficiency will make up for the power reduction. My 4180c will hopefully sound better at 4ohms as well.

Has anyone ever biamped a front stage? Was there a significant improvement?

-Fishy

that $1300 figure doesn't seem outrageous to me, a kx 1200.1 or 1000/1 is still $800 for Class D, so $1300 for A/B isnt as bad as it sounds i guess.

KikiTheCat wrote:Not always the case. A class D amplifier for example, spikes drastically in distortion levels as you approach peak output for the amplifier.

That might be the case, but it was assumed that you are within the limits of the amp.. once you get towards the amps limits different things can happen... but while the amp is well within its limits it wont sound any better than any other amp.

If you want to talk frequency response... thats fine.. class D doesnt have much higher freq response, but that doesnt matter when your only showing the sub 50hz and below... which is where most class D amps will be used.

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

Never mentioned reliability or longevity, that is of course the result of moderation, maintenance, and of course design plays a part.

The PPI amp may last forever... but there are much cheaper amps that will also last forever.

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.

Its not skimping... boss amps CAN do perfectly fine within their limits... its just the limits arent very broad. Most of the amps are also poorly designed and will fail for various reasons... but there are plenty of boss amps that were shown moderation that have lasted for years and years. Its just that most of the time you see these amps run at absolute full tilt all day... which no amp can stand over a period of time.

If you like spending ridiculous amounts of money on an amp... you are more than welcome. I understand the PPI amp has some collectors value... but saying its "the best sounding amp ever" or making other odd claims just isn't true. Perhaps "most overbuilt amp" is a better title?

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.

Just said there is really no such thing as an "SQ AMP"... its just a matter of getting the proper headroom.

Everytime I make a post, you assume its just to get on you, or start a fight... i just happen to find alot of unbackable statements made here.

The "foundation" behind no amp sounding any better than the other when run within its limits does have backing... If I can find any of the double blind tests that have been done to back this up I'll link them... but right now google isn't agreeing with me.

Whats next, RCA's and speaker wire = SQ? :)

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."

Regulated has its pluses... it also has its disadvantages. Saying it is the "best" way to go is like saying turbo is the best way to make a car faster... its not really the "best" in all situations its just a "different" way.

But... just letting those that dont know better that the PPI amp isn't some magic SQ amp that once put into your system will make it shine. It wont sound better than any other amp with similar specs... particularly at moderate volumes, which is what SQ is all about.

*its all install*

lotas wrote:that $1300 figure doesn't seem outrageous to me, a kx 1200.1 or 1000/1 is still $800 for Class D, so $1300 for A/B isnt as bad as it sounds i guess.

for subwoofer amplification... IMO A/B is inferior... sucks way too much current once you get to higher power levels.

spkrman wrote:The PPI amp may last forever... but there are much cheaper amps that will also last forever.

Its not skimping... boss amps CAN do perfectly fine within their limits... its just the limits arent very broad. Most of the amps are also poorly designed and will fail for various reasons... but there are plenty of boss amps that were shown moderation that have lasted for years and years. Its just that most of the time you see these amps run at absolute full tilt all day... which no amp can stand over a period of time.

Haha, now thats funny. The simple fact of the matter is they are so much cheaper for a reason. Wether its due to less design/engineering time, component costs/quality or build quality. If the three things I mentioned earlier were on par with other amps BOSS would cost just as much and have a good rep.

As far as BOSS's logevity I agree to an extent about what your saying. By Moderation do you mean 1/3 way on the gain or less ? The reason most people run BOSS full tilt all day every day is the noobs buy them as they dont know better. I cant say I know one person thats been into audio for any time that has BOSS ]If you like spending ridiculous amounts of money on an amp... you are more than welcome. I understand the PPI amp has some collectors value... but saying its "the best sounding amp ever" or making other odd claims just isn't true. Perhaps "most overbuilt amp" is a better title?[/QUOTE]

However you want to state it. The fact is this is one of the best amps ever built in our opinions as well as COUNTLESS others. There is nothing odd about it at all.

Have you ever heard one of these amps? Have you ever inspected the insides of one?

spkrman wrote:The "foundation" behind no amp sounding any better than the other when run within its limits does have backing... If I can find any of the double blind tests that have been done to back this up I'll link them... but right now google isn't agreeing with me.

Right... Go ahead and get your BOSS amp together and send it to me so I can do a heads up comparison. I have an ARC KAR 400.4 and 900.1D so send something comparable or slightly more.

I can gaurntee you the difference will be like night and day...

spkrman wrote:But... just letting those that dont know better that the PPI amp isn't some magic SQ amp that once put into your system will make it shine. It wont sound better than any other amp with similar specs... particularly at moderate volumes, which is what SQ is all about.

*its all install*

I beg to differ. If you pull out a Boss amp equivalent and place a PPI Art Series in you will notice a difference right away. You will also notice a difference in your checking/wallet.

lotas, while the JL 1000/1 is $1,100 today in 2005, keep in mind you're talking about the PPI A1200.2 costing almost $1,400 in 1993 or the PPI 2350DM costing almost $1,700 in 1988. Back then that was a tremendous amount of money, especially considering that "really good" subs of the day had all of about 7mm of Xmax.
It's not like you had a lot of call for really high powered amplifiers. Saying you had a thousand watts RMS of power in a car put you into the "Unlimited" classes of IASCA with the factory demo vans and such.. it was almost unheard of to have that much power in a personal daily driver car.
Now, every other ricer you pass on the road claims 5000 watts of power in their system,
They were different times back then. That's also why nobody complained about an Audiocontrol mic reading higher.. because people didn't hit what they do today in the average car, even in SPL vehicles.

spkrman, comparing the PPI amplifier to something like a BOSS amplifier is much like comparing a Mercedes SLK to a Ford Tempo.
Both cars will get you from point A to point B. Both probbaly get about the same gas mileage, and if you conform to the law, both probably do it in about the same amount of time. This does not make both cars "equal" however. While the Tempo is utilitarian and just as useful as the next car, that SLK is an engineering marvel by comparison, thanks to superior design and superior build quality, even if the driver will never really use the full potential of the car, as most drivers never would. It's about the quality of the design and the resulting product. It's about the graceful lines and the attention to detail. It's about knowing that every effort was made to offer the best product possible, without regard to cost. That's where the difference lays, and that's not a difference that everybody will appreciate, require, or even want.
A lot of people are happy with a Tempo.

KikiTheCat wrote:It's about the quality of the design and the resulting product. It's about the graceful lines and the attention to detail. It's about knowing that every effort was made to offer the best product possible, without regard to cost. That's where the difference lays, and that's not a difference that everybody will appreciate, require, or even want.
A lot of people are happy with a Tempo.

there ya go

mostly I was just trying to get across... the PPI isn't going to make your speakers sound any "better" than an equivelant amp.

Build quality you can't argue.

But honestly I think it looks a little hokey... but, so does alot of stuff from way back when

Basstronics wrote:Haha, now thats funny. The simple fact of the matter is they are so much cheaper for a reason. Wether its due to less design/engineering time, component costs/quality or build quality. If the three things I mentioned earlier were on par with other amps BOSS would cost just as much and have a good rep.

As far as BOSS's logevity I agree to an extent about what your saying. By Moderation do you mean 1/3 way on the gain or less ? The reason most people run BOSS full tilt all day every day is the noobs buy them as they dont know better. I cant say I know one person thats been into audio for any time that has BOSS ]

Moderation means don't leave it up all day everyday... like the boss amps are almost always used. Go ahead and buy the PPI amp, play it to severe clipping everyday for at least half an hour and see how long it lasts. Think it'll still "last forever"?

Still, boss/pyramid and such are the best selling amps... why? Because people dont really NEED "5000 watts" all they really NEED is the 500 watts the amp actually puts out. + it makes them feel better to say they have 5000 watts.

And again, some boss and pyramid amps have lasted for years and years and years... the ones that don't get beat on day in and day out for hours at a time.

On the same token, some boss/pyramid amps have set on fire for "no reason"... but on that same token, so have amps from EVERY company - mostly due to bad install.

However you want to state it. The fact is this is one of the best amps ever built in our opinions as well as COUNTLESS others. There is nothing odd about it at all.

Have you ever heard one of these amps? Have you ever inspected the insides of one?

Not arguing build quality, just arguing sound quality

Right... Go ahead and get your BOSS amp together and send it to me so I can do a heads up comparison. I have an ARC KAR 400.4 and 900.1D so send something comparable or slightly more.

I can gaurntee you the difference will be like night and day...

And you would perform a properly setup double blind test?

Where actual TESTING has been done... amp SQ is negligible... where there is some "audiophile" sitting in his living room swapping amps, one amp always seems to be heads n tails better.

An appropriate test would be to only use *one* amp. Play a song... and then tell the blindfolded person you are swapping the amp for a more expensive, super high end technological break through wang bang SQ amp... dont change a dam thing... 10 bux says a trend will show people saying the "super amp" sounds better. Why? Because at, for example, 4 grand, as opposed to the "300 dollar" amp you played before it better dam well sound better!

Most people only judge quality by the chunk of change it took to get them there... most people don't realize that a vette is faster than alot of the "exotics", why? Because its WAY cheaper, it *shouldn't* be faster.

I beg to differ. If you pull out a Boss amp equivalent and place a PPI Art Series in you will notice a difference right away. You will also notice a difference in your checking/wallet.

I don't believe boss makes a true 1200 watt A/B amp.

I know there was a test done in one of the stereo review mags I have... but I have a giant stack of em.

They compared some cheapy amp to some extremely expensive amp, and there was absolutely no difference. Of course, I couldn't be more vague :)

I still can't find any of these tests on google, which sux.

EDIT: here is one... read the results carefully... where there was a difference is where either: tube amps were used, or clipping was involved. Not exactly the best test.

http://www.pcavtech.com/abx/abx_pwr.htm

And one for speaker wire... which seems setup better.

http://www.pcavtech.com/abx/abx_wire.htm

Im not as versed or experianced with amps as some of you are, but I do know one thing. One of the other important factors is what power the amp is putting out, into what load. I've recently been looking for new amps and I ended up buying a PPI Art series 600.2 for my comps. and im still looking for a sub amp. My comps need ~300 watts into 4 ohms.
Even the "Cheap" amps that could do this are about $300, and they are class D. High end amps that can put out this power start at $700. The high quality build of the PPI almost 100% guarentees that im getting an amp that does what I need it to do, and will keep doing it for a long time. (as long as it was treated correctly.)

Where actual TESTING has been done... amp SQ is negligible...

spkrman, apparently you are on of those die hard RC disciples.

Nothing wrong with that, but you seem to be forgetting a couple things.

These "tests" that you speak of(Richard Clark's?) were incredibly controlled experiments. Both amplifiers were limited to inaudible distortion levels, were frequency matched, and were adjusted to produce the same amount of power. To say under normal circumstances that Boss and PPI amps sound the same is ridiculous. Its true that with enough EQing you could mimic the frequency response of an A600.2, but to reproduce the frequency and level of distortion as well as the headroom of an old school PPI producing a significant amount of output would be quite a feat indeed.

In addition I'd venture that 99.9% of the car amplifiers currently in use(PPI or otherwise) are used in a manner that produces a significant amount of distortion, much, much more than the limits set forth in RC's amp challenge. Whenever you hear someone give a description of an amp as "warm", "harsh", "clinical" or some other "emotional" response what they are really describing is the frequency response as well as the nature of distortion produced by an amp/driver combo.

I had an old school PPI(4200m) which sounded great on MB Quarts, but left something to be desired with A/D/S 320i's, yet I had a "brighter" SS Class A100II which made those 320i's sing. Sure, the Class A design may have resulted in less crossover distortion at higher frequencies, but was probably a better match for the A/D/S as far as frequency response goes as well.

Yeah, sound quality is subjective and there may be a few people out there who prefer the sound of Boss over PPI with a certain driver combo, but to say they sound exactly the same ain't gettin it with me nor, from the looks of it, most of the people on this forum.

-Fishy