• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

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

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
37,953
Likes
162,124
Location
Seattle Area
This is a review and detailed measurements of a "vintage" (1990) Aragon 2004 MKII stereo amplifier. It is on kind loan from a member.
Aragon 2004 MK II Review Stereo Power Amplifier.jpg


I like the v-shaped design to set it apart from countless other boxes. Speaking of boxes, this thing is massive. It was designed to house the double power 4004 version with the same power supply. Inside is dusty and I am not sure if it has been refurbished or not.

Aragon 2004 MK II Review Back Panel Vintage Stereo Power Amplifier.jpg


If anyone knows what it sold for originally please, post.

Reading online, it is claimed that Dan D'Agostino of Krell and now D'Agostino amplifier company fame did a lot of the electronic design.

Note: please ignore the "4004" designation on the graphs. I originally thought it was that unit and didn't realize otherwise until the end of the measurements.

Aragon 2004 MK II Measurements
Warm up was uneventful and is often the case, performance got (negligibly) worse, not better, contrary to popular opinion:

Aragon 2004 MK II Measurement Warm up Stereo Power Amplifier.png


Here is our usual dashboard of pushing a 1 kHz tone into the amplifier:
Aragon 2004 MK II Measurement Stereo Power Amplifier.png


There is a ton of power supply related noise. So I shut off the input and saw some amount of it still there:

Aragon 2004 MK II Measurement Residual noise Stereo Power Amplifier.png


More on this later. For now, SINAD of 65 dB is well below the average of all amplifiers tested to date (around 79 dB). Dominant distortion spikes are 2nd and 4th.

Dynamic range is actually very good:

Aragon 2004 MK II Measurement SNR Stereo Power Amplifier.png


Crosstalk is not:

Aragon 2004 MK II Measurement Crosstalk Stereo Power Amplifier.png


Swinging the other end again, frequency response is nice, flat and extended:
Aragon 2004 MK II Measurement Frequency response Stereo Power Amplifier.png


Multitone shows a lot of distortion spikes which is likely a combination of power supply noise and intermodulation:

Aragon 2004 MK II Measurement Multitone Stereo Power Amplifier.png


Here is distortion+noise vs output power:

Aragon 2004 MK II Measurement Power into 4 ohm Stereo Power Amplifier.png


As you see from our two reference amplifiers (dashed lines), the usual slope is pointing down. This is because noise dominates the measurements when output power is low but once we increase the output signal, it progressively becomes smaller and smaller part of the original signal so overall performance improves. Not here. The line is flat. My best guess is that power supply noise is proportionally increasing with output power. So likely the filter capacitors are not doing their job. It could be an original problem or due to them aging.

Same is true of 8 ohm load:

Aragon 2004 MK II Measurement Power into 8 ohm Stereo Power Amplifier.png


Allowing for a bit more distortion, power specs are met:


Aragon 2004 MK II Measurement Max and Peak Power into 4 ohm Stereo Power Amplifier.png


Changing the frequency and making the same power measurements we get:
Aragon 2004 MK II Measurement Frequency vs distortion Power into 4 ohm Stereo Power Amplifier.png


Distortion lines for 1 kHz and lower are actually above their higher frequency counterparts. This is backward of most amplifiers and again points to power supply producing more noise as lower frequencies rely on them more.

Conclusions
At first I thought that an amplifier produced in 1990 would not be "vintage" but then realized that was 30 years ago! Time flies as they say... It is hard to know if this amplifier is running at original spec. I did not get any information from the member on that front. Looking inside, it is dusty and components appear to be original but I could not look closely. As is, performance is not special. There is a lot of distortion and classic tests like crosstalk show weakness. So I would not go out of my way to get one unless you have massive space you want to fill with a big box amplifier.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

fordiebianco

Active Member
Forum Donor
Joined
Mar 11, 2020
Messages
203
Likes
363
Location
Essex, UK
*eyes his Marantz SM-80 suspiciously*
 

pma

Major Contributor
Forum Donor
Joined
Feb 23, 2019
Messages
3,005
Likes
6,035
Location
Prague
There is a ton of power supply related noise. So I shut off the input and saw some amount of it still there:

Aragon 2004 MK II Measurement Residual noise Stereo Power Amplifier.png

Thank you for the review. This amplifier does not measure well.
Re your noise measurement, my question is, again - what is 0dBrA related too ??? 4.47V (5W/4R)? The graph as posted tells nothing. If it is 4.47V, the result would be quite usual for AB amplifiers of those days. If 0dBrA is 1V, then the result is good.
 
OP
amirm

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
37,953
Likes
162,124
Location
Seattle Area
Re your noise measurement, my question is, again - what is 0dBrA related too ??? 4.47V (5W/4R)?
Yes. That is a quick grab of the dashboard which is always at 5 watts into 4 ohm load with the generator turned off.
 

anphex

Senior Member
Forum Donor
Joined
May 14, 2021
Messages
393
Likes
465
Location
Berlin, Germany
Is there a price to be found anywhere? I always give my ratings relative to the price tag sooo...
 

Jim Matthews

Major Contributor
Forum Donor
Joined
Mar 25, 2021
Messages
1,063
Likes
1,276
Location
Taxachusetts
I owned the 4004 variant, driving B&W 801s.

It was two of these, in one chassis.

It was OMG heavy.
The 2004 was $1500, back in the Day, the 4004 around $2250 (but neither ever sold at straight retail).

Had mine for nearly ten years and sold it for what I paid (back in the 1990s).
 

capitanharlock

Active Member
Joined
May 17, 2019
Messages
110
Likes
91
Measuring vintage stuff always poses big questions: Are the performance the original ones, or the aged components deteriorated them?
And, did someone modify anything?
So, it's a nice exercise, but I wouldn't get any conclusion on the original performances.
 

milosz

Senior Member
Forum Donor
Joined
Mar 27, 2019
Messages
396
Likes
1,116
Location
Chicago
I wonder if replacing the aging electrolytic capacitors and doing a bias, AC balance and offset adjustment would clean this amp up quite a bit. Maybe checking if any resistors have changed values radically over the years would be worthwhile, too.

I often read that it is suggested to "recap" old audio gear, I would like to see from before and after measurements if recapping really does improve performance.

In the case of an old Heathkit tube integrated amp that I fixed up for a friend, many of the capacitors - some film caps as well as electrolytics- had changed value, gotten electrically leaky or developed high ESR. But that was a 65 year old piece of equipment that ran pretty hot from it's tubes all it's life- I wonder if recapping this 30 year old solid state amp would result in measurable improvement.
 

pio

Member
Forum Donor
Joined
Oct 10, 2017
Messages
74
Likes
203
I owned the 8008 version which powered my old NHT 2.9's. I remember really enjoying that match back around '97 or so..
 

noel_fs

Active Member
Joined
Dec 12, 2018
Messages
246
Likes
150
vintages are 70s-80s and there is supposed to be lots of good ones

this one seems like the average hifi audiofool $3k amplifier
 

pma

Major Contributor
Forum Donor
Joined
Feb 23, 2019
Messages
3,005
Likes
6,035
Location
Prague
I wonder if replacing the aging electrolytic capacitors and doing a bias, AC balance and offset adjustment would clean this amp up quite a bit.

I really do not think so. It is an issue of wiring topology, PCB routing design and low amplifier PSRR. So very usual with power amplifiers of that era, class AB with linear PSU. And not easy to design properly with much better results. Time was/is precious in consumer electronic design. Who would pay someone to play around the thing for further 6 months. It was just good enough for the purpose.
 

Azathoth

Member
Joined
Oct 18, 2020
Messages
77
Likes
172
I'd probaby put a bottle of wine on the v shaped notch right there. I know it's not a good place to put your wine but I just want to.
 

Gorgonzola

Addicted to Fun and Learning
Joined
Jan 27, 2021
Messages
577
Likes
742
Location
Ontario, Canada
I wonder if replacing the aging electrolytic capacitors and doing a bias, AC balance and offset adjustment would clean this amp up quite a bit. Maybe checking if any resistors have changed values radically over the years would be worthwhile, too.

I often read that it is suggested to "recap" old audio gear, I would like to see from before and after measurements if recapping really does improve performance.

In the case of an old Heathkit tube integrated amp that I fixed up for a friend, many of the capacitors - some film caps as well as electrolytics- had changed value, gotten electrically leaky or developed high ESR. But that was a 65 year old piece of equipment that ran pretty hot from it's tubes all it's life- I wonder if recapping this 30 year old solid state amp would result in measurable improvement.
For people with an attachment to old piece of vintage equipment, I think the Aragon is an object lesson in why it's necessary to renew the equipment, especially, but not only, the power supply.

My Sonic Frontiers Line 1, 20+ y/o preamp, (partly an emotional attachment), I recently upgrade to "SE+". The upgrade included extensive renewal of the power supply. The upgrade was pricey; for that money I could have more than bought a Topping Pre90 or Schiit Freya Freya +.

gi.mpl
 
Top Bottom