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I'm a daily user of said old technology, mixed with an old DSP, though the DSP is roughly 17 years newer than the PPI amps. Together they play. From my understanding a class A/B amp will take to repairs much easier than a D class amp. Also being that they are through hole they are quite fixable for someone with enough knowledge.

For a friend I replaced caps in his PG M series amps (as well as an Outlaw and a Bandit). These amps are known for certain failing capacitors and if replaced in time they will extend the service of the amps and prevent the board from catching fire. I did it and I'm pretty handy but certainly no kind of professional anything. All amps are in working order and have yet to be put into service.

Are you nostalgic? If not then go with the digital sound and the small footprint.

I have never heard any of the JL Audio D class amps though so until then I cannot comment.
 

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I already posted on this thread, but I still use a rack of old school amps, on only two batteries in a hybrid vehicle. They are relatively inexpensive, well-made, pretty easy to service or replace, sound great, fit my nostalgia, etc. Several of these have been in the same car, and on the same power, for years now without problems. I have only increased the footprint of my install since I first got going on it.

The downsides are large footprint, and heat. But you aren't going to escape these concerns no matter which way you go. I am driving a tiny hybrid in AZ, by the way.
 

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From a purely practical standpoint the new class D amps are by far the better (smarter) choice, mainly for all the reasons already mentioned...footprint, efficiency, etc. I have a couple of them that are considered budget or entry level and I am astonished by how good they are. Unless you plan to compete, you would never know the difference in SQ.

Now, having said all of that I have to come clean....just this week I bought a huge old school Orion surfboard of an amp from 1999. Totally impractical and almost obsolete. But, man is it cool!
 

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From a purely practical standpoint the new class D amps are by far the better (smarter) choice, mainly for all the reasons already mentioned...footprint, efficiency, etc. I have a couple of them that are considered budget or entry level and I am astonished by how good they are. Unless you plan to compete, you would never know the difference in SQ.

Now, having said all of that I have to come clean....just this week I bought a huge old school Orion surfboard of an amp from 1999. Totally impractical and almost obsolete. But, man is it cool!
I read about footprint and efficiency benefits, but what about sound quality differences? Something the ear will hear? That's the conclusion I could not draw reading this thread. The THD numbers on the a/b section of my old amp are closely comparable to the new one I'm looking at. The class d section has a much better THD level in the new amp (1.5% vs 0.5%)

Sent from my D6503 using Tapatalk
 

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Pssst, its the tubes! Im using a jpl dual stage pre with a high powered class d. It's glorious , 3d, huge fleshed out sound. Only downside is increased noise floor with 4 dual triode tubes while listening at low volume in a comp sound lane but for everyday usage-Amazing!





Honestly, I doubt I will "come around".

You have to understand, one of these amps actually cracked my profound belief that a watt was a watt. I used to run a McIntosh MC431 on the front stage in my old GTI. At the time, I believed this was the best you could really do SQ wise short of adding another pair of channels for a full active 3 way system. I was running it bridged into a DLS UR36 Ultimate setup, as I didn't have DSP capable of making it work actively. I was worried that the tight install room in the GTI was going to cook my Mac though, so I begrudgingly decided to go to the local shop and find a more "modern" smaller amplifier that wouldn't run so hot. This was 2003 for reference.

Being the sound nut that I am, I ended up talking to an installer rather than a salesman, and happening into a deal on an amplifier I had never heard of, a TU-600, mostly because the installer had heard great things and really wanted to hear one himself. It was much smaller, less powerful, and supposedly inferior to the Mac, but I was already resigned to the Mac dying an early death if I kept it, so this became the the way forward.

Though all of this, I was expecting a downgrade in sound. The actual results blew my mind. The US Amps absolutely transformed the SQ of my system. Transients in particular went to level I had simply never heard of. This thing is a monster from a sonic perspective. It's level of control over a driver is something I have never heard before, or since.

So you see, I simply don't believe a digital amp has a hope of reaching this level. The "best" class AB amp in the world by many accounts had it's ass whooped in thoroughly convincing fashion by what I will be running, and the best class D amps are just starting to approach that Mac's level.

The only thing the "modern" amps have to offer to counter that is ease of install.

I do love modern DSP though. Truly the best thing to happen to car audio from an SQ perspective in it's entire history. Nothing beats the combo of high quality DSP running a fully active setup through old school single ended tube hybrids. :)
 

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I read about footprint and efficiency benefits, but what about sound quality differences? Something the ear will hear? That's the conclusion I could not draw reading this thread. The THD numbers on the a/b section of my old amp are closely comparable to the new one I'm looking at. The class d section has a much better THD level in the new amp (1.5% vs 0.5%)

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SQ is entirely subjective. Meaning, you and I will have different standards on SQ, basically because we ourselves are all slightly different. Our ears and the way our brains interpret sound differ from person to person.

Regarding those quoted measurements, was there any info about how the manufacturers arrived at those numbers? What frequencies, decibel levels, gain settings, etc? There are ways to manipulate test results and specs so, keep that in mind.

BTW, you might be able to hear 1.5% distortion in a very quiet setting with the vehicle perfectly sealed and all outside noise muted...but, I doubt it.
 

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Pssst, its the tubes! Im using a jpl dual stage pre with a high powered class d. It's glorious , 3d, huge fleshed out sound. Only downside is increased noise floor with 4 dual triode tubes while listening at low volume in a comp sound lane but for everyday usage-Amazing!
I've always wondered about tubes in the mobile setting. Are you using 12ax7's or ? Would switching to a 12au7 help with the noise floor issues? I ask because I have some experience with tube guitar amps and have seen a significant difference with that swap in my application.

Wondering how much the class D power amp section is altering or affecting the tube driven pre-amp signal. In the guitar amp world simply having a tube pre-amp section doesn't guarantee a nice tone at the speaker. The signal still has to transition thru the solid state power amp.
 

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12ax7 mainly it will do 12au7 lower gain still higher noise floor than without tube pre. I suspect a dsp controlled input and gain structure of something like the biketronics self biasing amps would be the ticket and maybe the next thing i try. It doesn't bother me but I'd like to see if i could recommend it to comp guys as it makes a world of difference.

Im not familiar with guitar amps but very much so with hifi tube amps. I can ascertain the different characteristics of each tube very easily just like at home. Im impressed
 

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I’m all in for the old school goodness,
I was into car audio in the mid-late 90’s, using mostly alpine and rockford fosgate gear.
Now that I’m building another project, I’m using gear from the same era, not only because i know how they sounded back then, but they were built out of china, and I’m a fan of quality over quantity, oh, and now they are soooo damn cheap to pick up!!!!
Krem
 

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Well I don't know about the newer brands and their amps just yet, just coming back to this but I can attest there was some good s**t produced in the 90s... even early 2000s. Stuff like Ample amps, I don't know if anything has come to the markets that can compete with that
 

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Keep in mind some of the highest scoring SQ cars to date are using class D.
That i of itself says it all.
Did you know that many of those “competition cars(class d-garbage)” aren’t so good for playing normal music! Is similar to Miss Universe contest!
 

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Did you know that many of those “competition cars(class d-garbage)” aren’t so good for playing normal music! Is similar to Miss Universe contest!
What are you talking about "normal music"? Some of the tracks used to judge SQ vehicles are among the finest recording you can find.
I seriously doubt you could tell the difference between a class D powered system and a old school class A/B setup in a blind test.
 

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My first decent amp was a HiFonics Odin IV I bought in 1986 – I ran that amp until 2007 and it was still going when I swapped it out for a new old stock Gen X Sampson I bought around 2002. I pushed that thing super hard up until around 1992 and still cranked on it quite often. The only difference in the old IV and the Gen X was a little better highs and the noise floor, or lack thereof in the Gen X – it’s basically nonexistent. It’s almost 2019 and I’m still running the Gen X amps in my current ride - I think they were made around 1998?? If so, then they’re twenty years old and still going strong.

On a related note, I literally pulled a HiFonics VI out of a flooded trunk wheel well from a buddy’s recently purchased hot rod back around 1990?? Took off the bottom plate, dried it out, used a couple cans of contact cleaner and a soft bristle brush to clean it up, cleaned up the rust on the end plates and shot a little paint on them, let it air out for almost a week,,, put it back together and ran the dog crap out of that thing until I swapped it out in 2007. I kid you not – felt like I stole it for the $40 he wanted for it.

Aside from putting in a couple systems for a few friends, including Cerwin Vega EXL, Blaupunkt THA, Boston GT4200, and JL HD amps, I can’t really speak to the newer amps and those I listed are getting old. However, based on my experience,,, I thought the old Blaupunkt class D amps were weak and hollow but those HD JL amps sounded pretty dang good to me. They didn’t sound any different to me than what I might hear comparing two old school A/B amps – which I have (Orion GX280, Hifonics IV, VI, Gen X, MB Quart RAA4200, Diamond D5s, Boston GT40 and GT42s).

Again, can't really speak on the quality of the new stuff, but every Zed made HiFonics I've own are standing the test of time.
 

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I just read every post here. Seems that people who only care about competing( whatever that means) goes class D. True audiophile and people wanting the best sound go class A or A/B. Just like home audio amps.
 

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If you were looking for a subwoofer amp for an inexpensive 10" today which would you choose given the same price:

Alpine MRP-T220 (circa 2003) or a brand new Rockville amplifier?
 

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I prefer class AB amps over class D. I also believe cost wasn't really an issue when building some of the good quality amps back in the 90s and early 2000s. I feel like almost every brand had a high quality amplifier to offer. You pretty much give up size and efficiency going with class AB. I definitely think the benefits of going to class D outweigh class AB amps for most people. I still think a good ol classic AB amp sounds better if the caps and components are rebuilt to spec.
 
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