some more info here: http://www.hbassociates.us/Aragon_Brochure_A1.html including specs for the original 2004
???the noise is somewhat like in a class D amp
Apart from the usual suspects (60Hz, 120, 180, 240...) there is a rather large wide spectrum of high frequency noise, isn't it?
I'd still be willing to bet that it would be indistinguishable from a new amp with similar specs that match the aragon when new.Sobering review for all the vintage amp hoarders out there who are too cheap to get recaps done (me)
If you are not then why are you posting detailed engineering comments?Apart from the usual suspects (60Hz, 120, 180, 240...) there is a rather large wide spectrum of high frequency noise, isn't it?
Not what I would expect from a 1990 amp (but I'm not an engineer).
The fact that it rises with signal strength suggests the noise is worse than the as-new performance level.
Yes. That is a quick grab of the dashboard which is always at 5 watts into 4 ohm load with the generator turned off.
Well, it does not rise much, in fact. Please look at the plots carefully. In the @amirm 5W/4ohm measurement, the noise floor is at -140 to -150dBr and the mains spuriae attack just below -90dBr. However, in his "noise measurement", the noise floor is at -130dBr (10-20dB higher) and mains spuriae are just above -100dBr. Why that big rise of the noise floor without input signal? Because there is a mistake in methodology. As @amirm replied to my question,
he just turned off the generator:Aragon 2004 MK II Review (Vintage Amplifier)
This is a review and detailed measurements of a "vintage" (1990) Aragon 2004 MKII stereo amplifier. It is on kind loan from a member. 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...www.audiosciencereview.com
He turned off the generator which resulted in undefined high generator output impedance seen by the amp input. Thus the rise of noise floor in the "no signal" measurement. The input had to be shorted or closed by a defined impedance, like 50 ohm or 600 ohm, instead. As such is now, the "no signal" noise measurement is pointless.
Aragon lists its THD spec as .06% which translates into a 64 db SINAD, so maybe Amir's measure of 65-66 db SINAD is really consistent with original design specs?There's some pics of the insides of the 4004 and links to some documentation in this AK discussion.
A pic from the brochure linked upthread:
View attachment 174094
Claimed A-weighted SNR at full rated power: 120 dB.
In the same "logic", you must be a physician to describe a skin rash when you see one? Or a designer to describe what you see or don't see in a given design, even in detail? If it were this way, this would be a very small (and IMHO boring) forumIf you are not then why are you posting detailed engineering comments?
Fair enoughIn the same "logic", you must be a physician to describe a skin rash when you see one? Or a designer to describe what you see or don't see in a given design, even in detail? If it were this way, this would be a very small (and IMHO boring) forum
I saw it this way, which could be wrong, as any opinion.
I owned an Acurus A150, an Acurus A250 and an Aragon 4004 MKII. That was back in my naive, subjectivist days.