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Aragon 2004 MK II Review (Vintage Amplifier)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 49 32.2%
  • 2. Not terrible (postman panther)

    Votes: 74 48.7%
  • 3. Fine (happy panther)

    Votes: 20 13.2%
  • 4. Great (golfing panther)

    Votes: 9 5.9%

  • Total voters
    152

Walter

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As a mechanic for well over 40 years, using oil analysis to do oil changes, the 3000 mile oil change was a myth (unless you had a VW Beetle that did not have any oil filter from the factory & was air-cooled, therefore running hotter or only drove on dirt roads & off-road). Since synthetics arrived in the early 70's (Amsoil) I have personally limited even my hotrod cars to one oil change a year (the oil analysis shows that I could go longer) but I believe that condensation due to weather changes & short run times (going to a grocery store 10-12 minutes from home, not allowing a long enough run to maintain operating temperature long enough to evaporate the condensation in the engine) would cause problems in the long run.
All my cars, (models from a 1968 Chevelle SS 396 to a 2012 Lexus [currently 30K miles], even my hot rodded Beetles (that were making 50 to 75% more power than from the factory), have gone 200K (some 300K) before needing an engine rebuild. The 3000 mile oil change was perpetrated by the oil companies & filter (oil & air) manufacturers (who enlisted the new car manufacturers to put short oil change mileage or times in the owners manual, to sell more oil & filters.
Popular Mechanics (I think) did a test where they concluded that it was fine to double the oil change interval if you just changed the filter, so that is what I did from that point on. It never caused a problem, but I seldom kept a car for more than a year or two.
 

H-713

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However: These particular amps run quite warm, if not down right hot. Time x heat hurts things. (& if the unit was not in use, was it stored in an attic in a house in the Mojave desert or in the basement of a house in Nova Scotia)? With no way of knowing, if I had one, I would change & modernize all of the things that I could without affecting the circuit design.
I wouldn't. It's probably about $150 to replace those four screw terminal caps alone. Sure you could come up with a board to use snap in caps, but that's a bit of a pain. Measure the leakage current and ESR of the existing caps. Nothing wrong with replacing them if you really want, but I see no reason to bother unless I have good reason to believe they are actually bad. I certainly wouldn't just assume they're bad - it's relatively rare that I see can caps from the 80s and 90s that are bad.
 
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The PS caps are fair bit away from the amplifier module. And the whole amp runs pretty cool so I don't think heat would have done much damage to them.
 

EJ3

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The PS caps are fair bit away from the amplifier module. And the whole amp runs pretty cool so I don't think heat would have done much damage to them.
Hot is what I had heard somewhere, perhaps just from a naysayer about these or someone who had problems with their setup. I stand corrected. Which is fine, this is how we learn.
I would still be concerned as to how it was stored. And would at least have them checked out as per H-713.
 

AndreaT

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a bit of history of Aragon electronics, and it's genesis as "Mondial Designs" -- copied from a post on the Klipsch Forums:

"Courtesy of the home theater / hifi website, we have:
Acurus was founded in 1992 as the value brand of Mondial Designs. Mondial was started with the Aragon brand, well know for its high end electronics in audiophile circles. Mondial was founded in 1986 by Paul Rosenberg and Anthony Federici, the latter of whom has since left the business. In December of 2000 Mondial was bought out by Klipsch of speaker fame. Paul Rosenberg is still with Mondial as the Director of Marketing and New Product Development.
The initial Aragon products were actually designed by Dan D'Agostino of Krell. About 11 years ago, Mike Kusiak joined Mondial as Chief Designer and is responsible for all products since, including the DIA150. All Mondial amplifiers have the same design philosophy, i.e., no integrated circuits, motorized volume pots, glass-epoxy circuit boards, large transformers, lots of capacitance and bipolar output devices.

Also, check out the review of the Acurus DIA150 at http://www.hometheaterhifi.com/volume_8_3/acurus-dia-150-integrated-amplifier-7-2001.html"

From my own memory -- As I was in the high end audio business back in the 80's and 90's -- Mondial came about as the brainchild of "Tony" Federici, who had been importing an Italian speaker line into the U.S. -- "ESB", and started Mondial as a marketing company -- he having had many contacts amongst the east coast major Hi End dealers of the 80's (Lyric in NYC, Sound Components in FL, etc.) as a Mfgrs. "Rep" and started Aragon with the assitance of Dan D' Agostino of Krell fame doing the electronics designs as a sub-contractor with Mondial.

(The name "Mondial" chosen for it's association with Ferrari and all things Italian, hence the importation of the Italian ESB speakers -- these being a visual copy of the very popular ADS large cabinet speaker designs)

Anyway, I'm not sure of which OEM mfgr. was making the Aragon amps at the time, but as we move into the early 90's, Mondial starts it's less expensive "Acurus" electronics line, made in So. Calif. by ATI (yes, that ATI -- who in the 70's and early 80's were known as "S.A.E" electronics -- owned by Morris Kessler -- I think Acurus is still made by ATI for Klipsch)

And so with Aragon at the "High end" and Acurus as the "Value" line, they continued on into the late 90's -- with some popularity for their "DIA" series of integrated amps, and later a CD player, and much later AV Processors for the beginning of the Home Theater craze that began to take over in the 90's. And today, Acurus still exists as a sub brand of Klipsch.

History lesson concluded -- any updates or corrections are welcome.
The Ferrari Mondial was a poor design and performance model as well, even for the standard of those days. Maybe he should have chosen “GTO” or “250GT”…
 
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Koeitje

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DSJR

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You know - and with some small knowledge of the priorities of the designer, this amp even now measures well *for the period* high end amps I'd say. We're spoiled rotten here with unbiased exposure to the latest and very best class D types (and the Benchmark of course) showing what modern design and components can do and I suspect many of us here aren't aged enough to remember the then burgeoning high end market in the 80's, where Class A was king (especially if it was a Krell where a third of the output was 'A sliding into AB for power over the spec). Distortion back then was judged irrelevant if the tunes came out OK.....

As for components and component ageing, I was told by a trusted UK amp designer that the really high power transistors didn't come on-stream until the early 90's (I need verification though), so many trad US designs had banks of output transistors instead to do the job. The other thing about cap life (and even amp life) is as much the quality of the parts used and how 'thrashed' in the circuit the electrolytics were. An amp I've bonded with for some reason is a 1990-ish HH VX300 MOS-FET pro model. 100WPC at 8 ohms (160W at 4) and >0.03% distortion, which had been used 24/7 for over ten years (maybe even twenty) before being decommissioned when the broadcaster rebuilt their editing suites. On a whim, I checked it last week to discover a blown bias resistor (the preset has a resistor each side) and nearly half a volt DC on one channel output. Easy for me to fix and it set up (two adjustments per channel) perfectly. Looking at the underside of the main board (output boards are separate and to the heatsinks on the side), you can see three substantial heat 'spots.' I already replaced the electrolytics on this board (the supply ones look fine but I haven't measured them) but I'm amazed how reliable these amps reportedly were, some with very hard 'on the road' use as well I gather. Bias resistors are middle and right of the bottom pic below. Not sure how similar many domestic high end behemoths fare in comparison at this age...

DSCF2894.JPG


IMG_20211221_141127423[1].jpg
 
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pma

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Tons of unshielded wires - I really do not like this kind of design school. And it always reflects in mains spuriae spectrum.
 

EJ3

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Popular Mechanics (I think) did a test where they concluded that it was fine to double the oil change interval if you just changed the filter, so that is what I did from that point on. It never caused a problem, but I seldom kept a car for more than a year or two.
Yes! Keeping the air filter clean is probably more important (for keeping stuff out of the oil that can get into the engine through dirty air, keeping the fuel economy up and keeping emissions down).
My 2000 Nissan Frontier Truck has 187K miles on it (currently the oldest car I own). I just sold my 2007 Honda Fit (in Guam because I deemed it not worth shipping to where I am at) with 54k miles on it. And I shipped my 2012 Lexus from Guam to where I am at (James Island, SC) which had 19K miles on it upon arrival a year ago. It now has 31K miles on it. So I tend to keep my cars a long time. I have never had any problems with any vehicles that I owned that where caused by an issue with annual oil changes. The oil was in the ground for many (perhaps millions) of years, it doesn't just go bad. It can get dirty or laced with chemicals (some of which is acids caused by reactions with moisture) & become detrimental to what is is lubricating. But oil does not 'just go bad' & need to be changed at some predetermined distance.
 

DSJR

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Tons of unshielded wires - I really do not like this kind of design school. And it always reflects in mains spuriae spectrum.
No audible hum whatsoever, but obviously, I doubt this range of amps was ever properly measured away from the factory - at least the mains carrying wires had protection at the IEC socket and nothing 'bare' at all behind the mains switch (looks like a dedicated moulded 'boot/plug!').

You think the HH is bad - you ought to see my Crown D-60's with exposed mains terminals for voltage selection dangerously below the bare underside of the top sleeve (I don't know of any amp being 'clumped' so badly these terminals shorted out but as many were used with the switched 2 pin outlets on the preamp with mains earth wire floating (all done in the signal returns back then I think), it'sd almost frightening. The HH had a mains grounding switch and use of that was audible in hum level...

Would be interesting to see if the Aragon tested here needs offsets checked (may not need recapping at all) and tweaked. Although the basic performance may not be transformed, it may balance the channels up better?
 

Jim Matthews

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Tons of unshielded wires - I really do not like this kind of design school. And it always reflects in mains spuriae spectrum.
This was a consequence of available assembly techniques, when these were made. For comparison, look at the layout of vacuum tube amps from the previous decades. Half of my amps had more iron (ferrite beads and rings) around the input and interstage wiring than in the transformers.

Today's products would not have been affordable, just twenty years ago.

The downside of this is difficult (if not impossible) repairs.
 

pma

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This was a consequence of available assembly techniques, when these were made. For comparison, look at the layout of vacuum tube amps from the previous decades. Half of my amps had more iron (ferrite beads and rings) around the input and interstage wiring than in the transformers.

Today's products would not have been affordable, just twenty years ago.

The downside of this is difficult (if not impossible) repairs.
Being 66, I remember the past products very well. It was still possible to make a decent PCB (ground planes for link level) and wiring design 30 years ago, even if it was not usual in commercial consumer audio. Cost savings vs. parameters. I am no fan of vintage audio.
 

AudioTodd

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The Ferrari Mondial was a poor design and performance model as well, even for the standard of those days. Maybe he should have chosen “GTO” or “250GT”…
Even the 500 Mondial of the early 1950's? 2 liter inline four, rear-mid mounted transaxle and de Dion rear suspension - a package that even suited Alfa Romeo well up to the 1980's in their sports sedans and coupes until the four was replaced with a six.
 

Sonny1

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I had a 4004 a long time ago. It got very warm in use like a big space heater. Nice in the winter months in my downstairs listening room. It eventually got very hot and that nasty burning plastic smell filled my house. They were able to fix it and set it to factory specs. I sold it for what it cost me to get it fixed. Sounded pretty good and was very powerful so I used it to power my active subs before I upgraded to a more powerful amp. On the subs I could t tell the difference but the smoke was troubling. In fairness the amp was 20+ years old at the time. It looked cool and was very heavy.
 

capslock

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This is a schematic of the 2004 (i.e. mki):

It sure does a lot of things right. Degenerated, cascoded long tailed pair. No current mirror but you get an NPN and a PNP LTP instead. Darlington VAS. Two drivers driving two each MJW15003/15004. Those are rated at 140 V, 20 A (250 W).

I really don't see what causes the very poor distortion behavior. Leaky power supply caps could explain the mains spuriae, but not the harmonic distortion. In terms of topology, the only thing one could wish for is a triple EF output stage. And those output transistors are rated at > 2 MHz, so pretty slow. Compensation seems to be mainly Miller type inthe VAS.
 

H-713

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This is a schematic of the 2004 (i.e. mki):

It sure does a lot of things right. Degenerated, cascoded long tailed pair. No current mirror but you get an NPN and a PNP LTP instead. Darlington VAS. Two drivers driving two each MJW15003/15004. Those are rated at 140 V, 20 A (250 W).

I really don't see what causes the very poor distortion behavior. Leaky power supply caps could explain the mains spuriae, but not the harmonic distortion. In terms of topology, the only thing one could wish for is a triple EF output stage. And those output transistors are rated at > 2 MHz, so pretty slow. Compensation seems to be mainly Miller type inthe VAS.

I'd like to see an EF3 in this particular design, since the MJ15003 / MJ15004 are pretty low-gain devices. VAS loading could be an issue depending on the VAS current.

Distortion could be an issue of VAS loading, but I think it is likely a layout / grounding issue.
 

capslock

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Good point about the layout, that could be an issue.

Yeah, EF3 is what I would have wished for, too. Then maybe a somewhat more elaborate compensation scheme. I would have expected distortion to rise with frequency as the loop runs out of steam, but we see the opposite. Maybe that is due to aged caps?

edit: overall lack of loop gain might also be a reason for highish distortion, given the 100 R degeneration both on the LTP and VAS.

Lastly, what was that amp rated at 100 W / channel doing with transistors capable of dissipating 2 kW per channel? There were better American transistors available at the time, and Japanese amps managed the same rating and much better THD performance with single or two pairs of perforated or ring emitter transistors.
 
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