Please note that I am indebted to Mike Kusiak for supplying me with quotable e-mails with corrections and additions to this guide. Quotes from him are in italics. I would also like to thank Steve Donalson and Adam Gershon of Klipsch for answering my questions in the Klipsch Forums.
Guides to Classic Aragon Amps and Aragon Source Components are also hosted here on eBay.
Aragon had a thing with precious metals. They introduced an amplifier called the Palladium, and the preamp line took it's name from the gold purity standard. The first preamp released by Mondial Designs/Aragon was the 24K. There were additional models released that were strongly related: the 24K SP and the Aurum, they are covered below. The 24K included a phono section, and a fairly good one at that. It had internal adjustments via tiny switches to adjust the phono section for accuracy with various cartridge loads. There were five additional line-level inputs, (labeled Tuner, CD, Aux, Tape 1 and Tape 2) and two tape loops. The 24K family of preamps use an outboard power supply, the power supply is plugged into the wall socket, then the output of the power supply is plugged into the back of the preamp itself. No A/C power is provided to the preamp, it has already been converted to 24V DC by the outboard power supply. An upgraded power supply, called the Isolated Power Supply (IPS) was an option. This power supply was shaped like a wedge, and had uprated components inside. Still supplying 24 volts, it had additional capacitance and was capable of greater amperage than the regular power supply. None of the 24K family are equipped with a headphone jack.
There was a fairly major upgrade to the 24K during it's production life: The early units had a volume potentiometer made by Noble (some say there was also an Alps volume pot used as well, but I have not confirmed this). The Noble pot is much better unit than is commonly used, but a still-better one made by Penny & Giles was also available. There is conflicting information about the P&G volume pot. Some sources claim that the P&G pot was an option, and had to be specially installed. Another source--which I trust but cannot absolutely verify--says that all 24K made after September, 1989 have the fabulous P & G volume pot.
[Sorry, I have NO control over photo size. My thanks to eBay for allowing larger photos than previously.]
P & G volume pot is round, and connected directly to the volume control knob but of course, on the inside of the chassis. (Noble pot is approx. 1" cube.) My thanks to Be_godwin for use of the photo.
Like most of the Aragon line up to the Klipsch buyout, the "Industrial Design"--the way the product looks, and to some extent the parts layout inside, is the work of noted designer Robbii Wessen. Robbii's hallmark styling motif on the amplifiers was to use a "V" shaped groove or notch in the top of the amplifier, directly over the large heat sinks, from front to back. A similar V styling motif was included on the preamp, but as part of the front face--the V is now sideways (<) and longitudinal across the face of the preamp.
An advertisement in the November 1988 Stereophile suggests a price "Under a thousand dollars", but of course the price went up over time. The October 1990 Audio magazine shows a price of $1250 for the 24K. A year later, Audio shows a price of $1500. The IPS would have been an extra cost, as would converting to the P & G volume pot if it wasn't equipped with one already.
24K Family--24K SP
The 24K was sold in a version that did not have the phono section. This model is the 24K SP. It has an additional line-level input (labelled "D/A") instead of the phono section, for a total of six line level inputs, and of course the two tape loops. It sold at a reduced price from the "regular" 24K. My information source says ALL 24K SP have the wonderful P & G volume pot, but I have not been able to independently verify the accuracy of that information. The 24K SP would have shipped with the standard power supply, the IPS would have been an extra-cost option. The October 1990 Audio magazine shows a price of $995, that increased to $1250 in the October '91 issue.
A replacement for the 24K and 24K SP was designed, and designated the 18K. Despite the name, which would represent a reduction in the purity of gold, the 18K was intended to be "better" than the 24K and SP that preceded it. The 18K has no phono section, but it did retain the outboard power supply. (Aragon sold a stand-alone phono section, the 47K, by this time) All 18K were shipped with the IPS. The 18K features six line-level inputs, (labeled CD, D/A, Tuner, Aux, Tape 2, Tape 1) two preamp outputs, and two tape loops. There is no headphone jack, however headphones can be driven from the preamp output jacks on the rear panel if an adapter is fabricated to allow a headphone jack to connect to the RCA jacks.
The 18K preamplifier was introduced in 1992 as a replacement for the 24K and 24KSP. The basic version came equipped with the Noble volume potentiometer, with the P&G as an optional upgrade. The circuit board was designed specifically with this upgrade in mind, as the Noble pot was mounted on a breakaway section of the board. This part of the board could be cut out and the P&G pot mounted in its place. The original 18K had a plain flat front panel to match the 2004 and 4004 amplifiers.
The original 18K was replaced by the 18K Mark II in 1995. The MK II
version came with the P&G volume pot as standard equipment, and had
a new beveled front panel to match the new 8008 series amps. The price
also increased at this time to cover the cost of the P&G and the
more expensive front panel.
The 18K's copper-plated circuit board showing wiring to input and output jacks
Aragon sold a preamp that used a 24K SP-styled case, (although most used a different color scheme from the black used on the 24K.) but inside it had circuitry based on, and upgraded from the newer 18K. The Aurum, therefore is a progression or upgrade of the 18K, but housed in the older style chassis and faceplate. It is considered the finest preamp made by Aragon. It came "standard" with an upgraded version of the IPS, called the Ingot. It was even more powerful than the IPS, having more than 50,000 microfarads of storage capacitance in the Ingot, vs. 20,000+ microfarads in the IPS. One balanced (XLR) output per channel was also included in addition to the two pair of single-ended (RCA) output jacks. The Aurum, therefore, shipped with everything that Aragon could do to the basic 18K circuit design that would improve performance. Of course, that meant that the P & G volume pot was standard. All the best circuitry was then installed in the "prettiest" packaging--the 24K-style chassis and faceplate. The February '93 Stereo Review and an advertisement in the April 1995 Stereophile magazine shows that it was also available in black, and had a list price of $1750. October 1997 Audio magazine shows a price of $1799.
Aurum; 24K and 24K SP similar except for color. Wedge- or triangle-shaped Ingot power supply in background. IPS power supply is similar.
A note on external power supplies:
Aragon sold several components that used an external "box" to house the power supply. All the preamps except the 28K, and the digital converters D2A and D2A Mk II, for example. All the power supplies (standard, IPS, Ingot) provided + and - 24 volts, but varied in the amount of storage capacitance. They are "somewhat" interchangeable as described below:
"The Ingot power supply can only be used with the Aurum. Although both the IPS and the Ingot supply the same plus and minus 24VDC, the output plugs are different. The IPS has a 3 pin XLR, while the Ingot uses a 4 pin XLR. This was purposely done so that users would not accidentally plug the power supply cord into one of the Aurum's balanced outputs which also used a 3 pin XLR. If you change the plug, you can use an IPS with the Aurum, or an Ingot with the other Aragon preamps [or other Aragon components that require an external power supply]. That also applies to the standard power supply: if you have the correct connector, it can be used on any of the external-supply components.
The October 1998 Audio magazine shows that the price for an IPS power supply is $250, this is in the "notes" column at the end of the Aragon 47K phono preamplifier description.
The "standard" power supply, showing the "plug in" for the wall socket as well as the XLR connector that attaches to the back of the preamp or D/A processor. My thanks to Dave's Retro Stereo Music and More for use of the photo.
Consumers demanded remote-control, and Aragon responded with the 28K. This preamp did not have a phono section, and the power supply was now internal, so the previous power supply boxes (standard, IPS, Ingot) cannot be used. High-quality parts were used, and the volume and balance controls are motor-driven by the supplied 6-button remote control. The remote will turn the power on/off, mute the output, adjust volume, and adjust balance. It will not change input sources. There are six line-level inputs, two tape loops, and two outputs via RCA jacks. There is a +5 volt input for use as a trigger signal to remotely turn the unit on. There is no headphone jack, however headphones can be driven from the preamp output jacks on the rear panel if an adapter is fabricated to allow a headphone jack to connect to the RCA jacks.
Audio magazine, October 1997 shows a price of $1,199
Home Theater Processors
The original Home Theater Processor (HTP) from Aragon was the Soundstage. This supposedly has the analog circuit design of the well-regarded Aurum 2-channel preamp, multiplied for 6 channels, and combined with sophisticated 5.1 channel surround-sound processing. Although originally built as a six-channel (5.1) device, the company later offered a group of upgrades that permitted 7.1 channels and other enhancements. Sadly, they are no longer offering the upgrades. The point is, a very few Soundstages will be 7.1 capable, and most only 5.1. There are some enthusiasts who consider a fully-upgraded Soundstage to be "the" premium processor from Aragon. In part, this is because the Soundstage offers balanced (XLR) and single-ended (RCA) outputs. The Soundstage garnered excellent reviews for both sound quality and ease of use, despite being "handicapped" with a lack of on-screen-display. There is a 6-channel (8, if upgraded) analog bypass mode so the analog multichannel output of a DVD-A or SACD player can be accommodated. You will need a special interconnect cable set (or adapter cable) for the analog bypass input--the Soundstage uses a DB-25 connector for the multichannel analog input instead of the more common RCA jacks. Cables are readily available from several sources, including a "DB-25 to female RCA" adapter cable at low cost from Onkyo/Integra, this cable being used with 6 (or 8) regular interconnect cables.
The Stage One is a 7.1 channel, THX Ultra2-certified outgrowth of the Soundstage, but using Klipsch-inspired cosmetics. Again, it is advertised as using the Aurum preamp as a genesis for the analog circuitry. There are no balanced outputs, however, and I understand that the power supply has been reduced in size from what was built into the Soundstage. USA-spec versions include an AM/FM tuner, however the tuner was omitted from some export models. When the Stage One was discontinued, leftover export models with no tuner were converted to operate on "American" house current, and offered for sale in the USA at a discount. Original list price was $4000, once discontinued they were commonly discounted to $2,999 or even less, and the no-tuner version went for $2300 or less. The tuner was, therefore, NOT "optional"; it was standard equipment on North American Stage Ones; except for those leftover "export models" that were reworked and sold in the USA after the product was discontinued.
The Stage One covers the usual alphabet of decoding formats: Dolby Pro Logic II (but not IIx), Dolby Digital, DTS, THX Surround EX, DTS ES Discrete and Matrix, DTS Neo:6. There are also Party, Club, 5-channel Stereo, and Mono options. The Stage One is old enough that it does not include DTS 24/96 decoding, nor does it have Dolby Headphone (or any headphone jack at all!) There is no phono section. It uses identical 24-bit Crystal digital-to-analog converters, and 24 bit analog-to-digital converters, while some manufacturers use lower-grade chips for the surround channels.. The Stage One is capable of software upgrades via an RS-232 port, however as of this writing (27 October 2012) no upgrades have been offered.
Like the Soundstage, the Stage One uses a DB-25 connector for it's 8-channel analog input. This requires a cable set that has a matching DB-25 connector on one end, and the standard RCA jacks on the other. An alternative is the low-cost adapter cable from Onkyo/Integra, as mentioned in the Soundstage section above. I purchased an 8-channel RCA-to-DB25 cable years ago from Cobalt Cable for about a hundred bucks. Sadly, Cobalt Cable is no longer in business.
The Stage One uses a Phillips Pronto Neo "universal" remote. A wonderful alternative to using a dedicated remote. This universal remote has a touchpad, backlighting and in all ways truly outclasses a dedicated remote.
Indy Audio Labs now owns the Aragon and Acurus trademarks and rights to manufacture. New product is being designed and dealers for various territories are "signed up".
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