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8 0 0 8 A N D I R I D I U M U S E R G U I D E
©2012 Indy Audio Labs, LLC all rights reserved / Revision20130220
Document No. 1000571
Under the hood, the IRIDIUM and 8008 share similar
amplifier circuits with the IRIDIUM running its two chan-
nels in a differential, or BTL (Bridge-Tied-Load), configu-
ration. However, to achieve optimal performance in a
bridged configuration, small but significant adjustments
must be made to the amplifier’s high-frequency compen-
sation circuitry and power supply rails. Like the Pal-
ladium before it, the IRIDIUM is not simply a “bridged”
8008, but is optimized specifically for mono operation.
The new 8008 circuitry consists internally of two in-
dependent power supplies. Identical to its forerunner
Mondial 4004 MK II and 8008 designs, two massive
0.5kVA toroidal transformers feed pairs of 35A bridge
diode rectifiers. These supply signals are then filtered by
more than 140,000uF of capacitance to deliver clean +/-
70 volt power rails to each channel. The IRIDIUM power
supply is more than twice that of the 8008 on a per-
channel basis because it’s built around a single massive
1.2kVA toroidal transformer feeding all four 35A bridge
rectifiers and 140,000uF of capacitance.
Both the 8008 and IRIDIUM use a discrete symmetrical
amplifier circuit topology. No ICs are used in the signal
path. Instead, some of the latest low-noise, high-voltage
discrete semiconductors are used throughout. All
Aragon models are DC-coupled input-to-output. Zero-
offset is maintained by a newly designed servo circuit.
The control and monitoring sub-system integrated with
this latest generation Aragon amplifier features several
advancements in thermal management and fault protec-
tion over prior designs.
Components are hand-selected for quality and reliabil-
ity. The new Aragon models employ precision-sorted
semiconductors matched across several parameters
for each amplifier. For the output section, this helps
ensure optimal current load sharing among devices,
improves linearity-vs-power, enhances thermal perform-
ance and helps ensure long-term amplifier life. The input
stages and current mirrors take advantage of precision
audio transistors with low-noise, wide bandwidth and
tight matching. The VAS stage uses low-capacitance,
high-bandwidth transistors with input buffering. The
8008 output section utilizes 12 discrete bipolar junction
transistors (BJTs) per channel while the IRIDIUM output
section features 24 separate and discrete BJT devices;
this allows the IRIDIUM to drive 2-ohm loads to nearly a
kilowatt when necessary.
Both the IRIDIUM and 8008 designs employ many of
the same North American suppliers of power supply
components (such as computer-grade capacitors and
toroidal power transformers) that built components for the
original Mondial products. As a result, these amplifiers
