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Old 1st March 2008, 02:20 PM   #101
ppia600 is offline ppia600  United States
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quoted from nsxxtreme:

"Sure that's a valid point. But we had plenty of those amps in the 90's and 80's. So saying we had them now and not before really isn't valid."


During the 80's to early 90's there were more amps with real rms ratings and less with crazy peak ratings. You can look at the first sony, jvc, alpine, kenwood, lanzar, etc.. and see that their original amps have way better quality than the current models. Sure they have advanced to using class d in several of their amps but their "old school" counterparts were built better overall.

I can only remember a few cheapo amps from the early 80's, for example hitron, rockwood, kenford, pyramid. Back then pyle, sherwood, lanzar and alphasonik were not thought of as cheap generic amps, they were brand name.
When I refer to old school I'm talking 1980 to 1990. Moving into the mid to late 90's a lot of things changed.
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Old 1st March 2008, 05:02 PM   #102
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ppia600:
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I can only remember a few cheapo amps from the early 80's, for example hitron, rockwood, kenford, pyramid.
The word Kenford still makes me giggle. And people actually bought that stuff.

davesaudio:
Quote:
I had a Craig "Powerplay" amp early 70's and a "Lear Jet" cassette.
There really were plenty of cheapo's in the 80's. Craig and Lear Jet were still around and had made little improvement since their 70's products.
There were tons of brands like MEI, Unic, Jetsound, Targa, Fultron, FAS, I'm getting queasy thinking about the old 200W underdash EQ/boosters. Most of them made amps that fell between not good, pathetic, and questionable to even label as an amplifier.

A big difference between now and then was the power booster. More entry level and budget systems used them in the old days, and they just aren't around anymore. Cheapo amps solely cater to that segment of the market now, hence there are more available.

ppia600:
Quote:
And since some amps will produce 100w at .05 percent thd at any frequency from 10 to 50khz and others will only produce 100w at .05 percent at 1khz or a similar or limited range, you can actually hear a difference between a well built old school amp and a newer generic version
Absolutely agreed, but...One thing that hasn't changed over the years is the ears of the average buyer. When's the last time you heard a thumpin car ride by that actually sounded good? Even if it's got good products inside, chances are good that the driver has it cranked well into nasty THD. At that point arguing over details in power rating is moot.

Therefore, inferior products continue to sell as they morph to mimic the state of the art when most buyers don't know or care about the difference. That's captalism, and it's market driven.

We aren't the market, we're a niche. Fortunately, there are support groups like this one to help us cope with our problem! Hopefully, the niche will remain large enough for some decent products to continue to thrive.

Tim
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Old 1st March 2008, 05:39 PM   #103
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Quote:
Originally posted by nsxxtreme
Not that it matters but I have a MS in EE. Does that really matter? Your qualifications are? This isn't a peeing match can we carry a civil conversation without beating our chest about how smart we think we are?
[/B]

nsxxtreme - are/were you affliated with Phoenix Gold (since you're so close...)? I mean...not everyone can buy an NSX.
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Old 1st March 2008, 05:40 PM   #104
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Quote:
Originally posted by tsmith1315
ppia600:

........We aren't the market, we're a niche. Fortunately, there are support groups like this one to help us cope with our problem! Hopefully, the niche will remain large enough for some decent products to continue to thrive.

Tim
Well put, Tim.

My All-Alpine may or may not be old-school, but it sure sounds good. All of the components were Made-in-Japan, not Korea, Singapoer, Taiwan, and my favourite Communist China.

7618 (late 80's early 90's)
3681 (same era)
4381 (optional remote controller for the 3681)
3331 (definitely late 80's)
3522S x 4 (early 90's)
3527S (same)
6258 (pair) (~1992-3)
6257GD (pair) (~1994-5)
Pyle 8" subs OK, so it's not ALL Alpine, but close! (I don't remember the model#, but when they had problems, after I contacted Pyle in Indiana, they asked for them back, and promptly sent me new ones!)

Originally, I used the 3527S to drive the stereo subs, but then I stumbled across 2 more 3522S's and decided to individually drive each 8" sub by its own dedicated amplifier.

Total absolutely max. power: 320W
Total average power: a more realistic 60-70W, which proves, you don't need to take out a second mortgage, or install three more alternators for a 2MW system to have good sound.

Cheers,

Steve
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Old 1st March 2008, 05:47 PM   #105
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Quote:
Originally posted by tsmith1315
When's the last time you heard a thumpin car ride by that actually sounded good? Even if it's got good products inside, chances are good that the driver has it cranked well into nasty THD. At that point arguing over details in power rating is moot.

Tim
There is one guy in my neighborhood driving a well-tricked-out late-model Suburban whose system actually caught my ears (while mowing the grass, no less). Sure, he was playing some rap music - but man, it was CLEAN. The midbass hit you in the chest as he drive by and the subbass rattled the windows. Nothing on HIS car was rattling, though. I, for a moment, was jealous.
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Old 1st March 2008, 07:06 PM   #106
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Originally posted by EnvisionAudio
nsxxtreme - are/were you affliated with Phoenix Gold (since you're so close...)? I mean...not everyone can buy an NSX.
No not I'm not affiliated with Phoenix Gold. Watching Phoenix gold go from the top to a little bit better then average is truely sad. I went to the last of their friends and family sale when they were still Phoenix Gold. I picked up some really nice equipment for cheap. Even got a PG home audio amplifier 12x60w for dirt cheap.

I work for a far larger company in Oregon. I'm an asic designer in my day job. This is just a hobby and what I do for fun.
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Old 1st March 2008, 07:16 PM   #107
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During the 80's to early 90's there were more amps with real rms ratings and less with crazy peak ratings. You can look at the first sony, jvc, alpine, kenwood, lanzar, etc.. and see that their original amps have way better quality than the current models. Sure they have advanced to using class d in several of their amps but their "old school" counterparts were built better overall. [/B]
I think now we are just seeing a standard used that never used to exist and is far mor generous then what was used previously.

It is truely sad seeing your favorite brands got from the top of the game to falling to budget amp status. Many have fallen. And there is no question that amps made in the past were built better then amps today (quality wise). Which is why I would buy one and use it before I bought a new amp.

For Mids and high duty I prefer class AB designs and both amps made today and in the past can handle this job. For subwoofer duty I am willing to make the trade off for efficientcy. Which I recently picked up a used PG x600.1 to power my subs for $150. I picked up a blown JL 500/1 just for the fun of repairing it. The protection circuit in it has been a pain.
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Old 1st March 2008, 08:02 PM   #108
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Quote:
Originally posted by nsxxtreme


I think now we are just seeing a standard used that never used to exist and is far mor generous then what was used previously.

It is truely sad seeing your favorite brands got from the top of the game to falling to budget amp status. Many have fallen. And there is no question that amps made in the past were built better then amps today (quality wise). Which is why I would buy one and use it before I bought a new amp.

For Mids and high duty I prefer class AB designs and both amps made today and in the past can handle this job. For subwoofer duty I am willing to make the trade off for efficientcy. Which I recently picked up a used PG x600.1 to power my subs for $150. I picked up a blown JL 500/1 just for the fun of repairing it. The protection circuit in it has been a pain.
You're not the first person I've heard say that. What, specifically, makes the JL difficult in this regard? I've never had the opportunity to work on one, so I'm of little help...
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Old 1st March 2008, 09:35 PM   #109
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JL amps, and the 500/1 in particular, are some of the most difficult to repair for several reasons.

The stacked boards in the 500 prevent access to the components unless you make a set of jumper cables. The amp will not operate without having the preamp board connected to the main board.

Generally, when you begin working on an amp, you recognize the majority of the circuits and only have to determine how the amp is laid out to understand it fully. There is almost nothing recognizable in the JL 500. Of course, you recognize the main power supply and you can figure out where the output transistors are but beyond that, everything else is foreign. It's one of the few amps that use logic gates. This one uses them in the drive circuit for the class D audio amp. It's a very good amp but it's definitely not a clone.

In the JL 500, there are 3 power supplies. They don't power up at the same time and don't power down at the same time. There's even a difference in the operation of those supplies between the different versions.

Generally, when they fail, all you have to do is replace the power supply transistors, the gate resistors and 2 of the output transistors. When the damage involves a different part of the amp, the repairs can be much more difficult.
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Old 1st March 2008, 11:03 PM   #110
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Quote:
Originally posted by Perry Babin
JL amps, and the 500/1 in particular, are some of the most difficult to repair for several reasons.

The stacked boards in the 500 prevent access to the components unless you make a set of jumper cables. The amp will not operate without having the preamp board connected to the main board.

Generally, when you begin working on an amp, you recognize the majority of the circuits and only have to determine how the amp is laid out to understand it fully. There is almost nothing recognizable in the JL 500. Of course, you recognize the main power supply and you can figure out where the output transistors are but beyond that, everything else is foreign. It's one of the few amps that use logic gates. This one uses them in the drive circuit for the class D audio amp. It's a very good amp but it's definitely not a clone.

In the JL 500, there are 3 power supplies. They don't power up at the same time and don't power down at the same time. There's even a difference in the operation of those supplies between the different versions.

Generally, when they fail, all you have to do is replace the power supply transistors, the gate resistors and 2 of the output transistors. When the damage involves a different part of the amp, the repairs can be much more difficult.
That's quite a statement coming from your line of expertise. I've worked on some amplifers with logic gates in the protection circuit (Audison) and have designed a few that use the 74-series schmitt trigger in the Class D triangle generator and, likewise, 4xxx logic for synchronised supplies. One of my latest car amp designs uses a booster supply that drives the SMPS MosFet gates at 15-16V to ensure snappy turn-on even with low input voltage. Maybe this is something JL Audio is doing. Doesn't sound that scary to me...

I agree with nxsxtreme - I'd buy one to learn how it's done and become one the best at amplifier repair, but I'm not formally in the industry anymore. I've drifted away as new amps have come out!
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