|
 GENERAL INFORMATION
|
Are there reviews of Audible Illusions products? |
| Yes, during the past
eighteen years, there have been over 150 complimentary reviews of our products. *(Please
refer to our Reviews Link Page) FAQ |
What significant contributions have Audible Illusions products made to
the audio industry? |
Over the years we have
produced thousands of audio preamplifiers which have given much pleasure to music lovers
world-wide. Audible Illusions is proud to have been a pioneer in modern single-ended tube
design.
- In the early 1980's other audio
companies still manufactured preamps based on the venerable 12AX7 tube with cascode
circuits, cathode followers and negative feedback, etc. We were one of a few companies to
completely base our preamp designs on the 6DJ8 dual triode.
- Audible Illusions was also one of the
first audio companies to incorporate automatically muting turn-on safety circuits which
prohibits a tube preamp's dc voltage surges from damaging audio circuits in case of AC
power failure.
- The first audio company to employ
bare, oxygen-free copper traces on our PCB’s with Teflon solder masks. We continue to
hand-solder our circuit boards with silver-bearing solder.
- A.I. developed a special
"filament-on" soft-start circuit which greatly extends tube life.
- We were one of the first audio
companies to design very fast, low-impedance FET regulated power supplies to support our
audio designs.
- First to develop a stable, open-loop,
no-feedback line stage which significantly improved sonic performance of our
preamplifiers.
- We were first to parallel tube stages
to lower output impedance thus eliminating the need for cathode followers.
- And, one of the first companies to
use pure film-foil capacitors in our audio circuitry.
Today we take pleasure in noting
that most modern tube preamplifiers are based on the 6DJ8/ 6922 triode and that many of
our refinements are now used by other audio manufacturers. FAQ |
Why does A.I. manufacture both tube
and solid-state equipment? |
| It is our belief that,
for low-level amplification, tube designs are best. For power amplifiers we feel solid
state is superior due to the complexity of various speaker loads. Our primary
consideration is that both technologies be faithful to the music. FAQ |
What
is the minimum break-in period for A.I. equipment? |
| It has become common
knowledge that all high-end audio products require a break-in/burn-in period. Audio
equipment can sound somewhat harsh and two dimensional until various internal components
have broken in. Electrolytic
power supply caps and all parts having any insulating material require the most burn-in.
Tubes, FETS and transistors also take time.
Minimum "break-in" time
for our preamps is 3-4 weeks of normal operation. Our preamps still sound excellent
"right-out-of-the-box" but the open, multi-dimensional sound these preamps are
famous for won’t occur until the complex dialectic structure in our proprietary film
capacitors completely forms. After break-in, further sonic improvement continues with
additional time and will continue to improve over an extended period.
Our power amplifiers also require a
minimum break-in period of 2-3 weeks with continued sonic improvement over a period of
time. FAQ |
Should
power conditioning or noise filtering equipment be used? |
| In recent years there
has been considerable development in quality power conditioning and noise filtering
devices as audiophiles have discovered the sonic advantage of clean AC power. We understand that good audio designs must be
able to reject extraneous noise. Considering that high impedance tube circuitry is
susceptible to such noise we design our products in such a way that noise is not
superimposed on the amplified musical signal.
Generally, we believe that our tube
preamplifiers should be plugged directly into a discrete wall socket providing the AC is
reasonably clean. However, if excessive residue of DC or other artifacts are floating on
the AC line, we then recommend a quality conditioning device.
Most modern, high-current power
amplifiers will benefit from quality power conditioning. Very few amplifiers have adequate
AC line conditioning and the ones that do are very expensive. FAQ |
What
is ground loop noise? |
| When two separate
components, i.e.: preamp and amplifier, are plugged into two separate AC circuits a low
frequency hum is generally amplified with the musical signal and is heard through the
speakers. This problem is usually solved by plugging both components into the same circuit
or by "floating" the AC ground lead of one component using a "cheater
plug". A more thorough description of this problem, with suggested remedies, can be
located on the website of our dealer in the UK: www.walrus.co.uk/tech/tech.htm FAQ |
What
Interconnect cables are recommended for use with A.I. equipment? |
| Almost all
interconnect cables will work with our equipment. However, please understand that all
interconnect cables have a sonic identity. Interconnect cables have measurable resistance
and capacitance and when you put a resistor and a capacitor together, guess what, you have
a tone control! You should keep this fact in mind if you desire to have accurate musical
reproduction. Try to keep the resistance and capacitance of your cables at a minimum value
for the required length. FAQ |
What’s
the difference between balanced and single-ended designs? |
| Basically two types of
electrical interface between audio components are used to connect audio equipment,
single-ended and balanced. Audible Illusions uses both. However, after years of preamplifier and
amplifier design and research we have come to the following conclusions. For our tube
preamplifier designs we feel the "simpler-is-better" single-ended design
approach is best for sensitive low-level amplification. For our more complex solid-state
amplifier designs we feel that, in addition to a single-ended input, balanced circuitry is
necessary in order to minimize common mode noise.
A brief description of these two
design styles are:
Single-ended designs use a single
conductor cable to transmit the + waveform and a ground- shield conductor to transmit the
- waveform. The audio amplification circuit requires only a positive amplification circuit
with the negative tied to ground. This circuitry requires less parts but the designer must
be careful in executing the circuit with respect to minimizing extraneous noise from being
superimposed on the musical waveform.
Balanced audio designs use separate
circuitry for both + and - waveform amplification. Thus the interconnect cables must
contain separate conductors for both as well as a third ground conductor and an overall
shield. The circuitry is more complex and more expensive but we feel necessary in
high-level amplification, particularly if the amplifier is interconnected with a long run
of cable that might be susceptible to AC line interference or other noise. FAQ |
My
audio system doesn’t sound as good as other systems I’ve heard. What can I do? |
| The search for audio
perfection can be a frustrating experience. Assembling a great system requires more
knowledge than money and does take time and patience. Be advised that most of our
authorized dealers are very experienced in setting up audio systems and with proper
room-tuning. We urge you to work with your dealer and, if you need additional assistance,
please feel free to contact our customer service department. We look forward to you having
an audio system that reflects your needs and sensibilities. FAQ |
What
is the normal delivery time for A.I. equipment from date of purchase? |
| All Audible Illusions
products are "made to order" and require a minimum of 2-4 weeks for delivery
from time of purchase. However, for convenience to their customers, some of our major
dealers do maintain limited stock. FAQ |
Additional
technical information posted on some of our dealer's websites. |
| www.gcaudio.com/Archives/gcaarchives.html www.walrus.co.uk/tech/tech.htm
www.tweakshop.com/Tube care.html
FAQ |
| AUDIBLE
ILLUSIONS TUBE PREAMPLIFIERS |
What is
the purpose of a preamplifier? If you don't play records is one really necessary?In order to be able to drive an amplifier
properly, there must be some device to switch the various line sources such as CD, tuner,
tape etc. However there are other important reasons to use a preamplifier.
In recent years various
manufacturers of digital audio equipment have strayed from the industry standard of line
source equipment having an output of 1 to 1½ Vac. They are now producing their equipment
with voltage outputs far in excess of 2 Volts in order to drive amplifiers directly, thus
bypassing the preamplifier. Several of these companies are also including passive volume
controls and switching functions in their products. We have also evaluated power
amplifiers with passive volume controls on their inputs. Unfortunately, most of these
controls and switching devices are of poor quality and seriously degrade sonic
performance.
Another trend has been to develop
outboard, stepped-attenuator volume controls. While some of these controls are
manufactured to high standards they are incapable of driving amplifiers of normal input
impedance. Also, with low-impedance amplifiers we measure excessive high-frequency
roll-off. Another problem is that these passive controls cannot sufficiently attenuate the
excessive peak voltages from many of the "hot-output" digital players currently
in production. The result is that many amplifier input stages are being badly damaged.
A well-designed audio preamplifier
must not only be able to interconnect/switch a sufficient amount of input devices, it must
be able to optimally match impedances. Additionally, the preamplifier has to withstand
peak input voltages without circuit overload and protect an amplifiers input stages.
Another requirement is that it be low in distortion and sonically neutral. Indeed modern,
multi-component, audio systems require well-designed preamplifiers. FAQ |
Historically,
why have there been so few great sounding preamplifiers? |
| In audio design
it’s generally considered that a preamplifier is the most difficult to design. Not
only must these designs be able to amplify low-level signals, they must do this over a
wide frequency range with minimal distortion and resolution of musical detail.
Furthermore, if the preamp has a phono stage, the additional complexity of RIAA
equalization adds to the problem. Audio designers, like great chefs, all use the same basic ingredients and
recipes/designs. Also, most designers have their own interpretation of how their product
should sound. Unfortunately, listening to music is a very subjective process and very few
audio designers reference their designs to live musical performances. Thus, there are many
individual interpretations of audio equipment and it’s hoped that one of these will
"catch on" and appeal to a large enough group of audiophiles to make the product
financially successful. This design practice has proven to be very risky with hundreds of
preamplifier designs fallen by the wayside. FAQ |
What
Makes A.I. Preamplifiers so unique? |
| Audible Illusions
believes in taking a proven audio design and refining it. In researching great audio
designs of the past we have determined that, for low-level, amplification single-ended
triode designs are the best. Single-ended
audio designs have been around for many years. What makes our preamplifier designs so
successful is the incorporation of modern technology and specially designed parts into
these basic circuit designs.
Our designers understand the
superior linearity of a quality vacuum tube design. They also believe that these circuits
must be kept simple with single gain stages and no error correcting feedback. Add to this
ultra-fast, low-impedance power supplies that can supply voltage to meet the demand of
complex musical waveforms and you have the beginnings of a great audio preamplifier.
It is also interesting to note that
all of our products are completely hand-soldered using a special silver solder and
carefully assembled to exacting specifications. For the sake of optimum sonic performance
we have discontinued automatic wave-soldering machines. We take great pride in the quality
of our circuit board workmanship. FAQ |
Why
don't A.I. preamps have tone controls? |
| Our preamplifiers are
"purist designs". We strive to manufacture them to be absolutely faithful to
musical reproduction. However, while we realize that the original performance is sometimes
altered in the recording process, Audible Illusions will add no further coloration. FAQ |
Absolute
Phase. What does it mean? |
| An amplified audio
signal/sinewave consists of a positive half and a negative half and both should correspond
to the positive and negative polarity of the transducer/speaker used to convert the
electronic signal to sound waves. If the equipment is connected properly, full fidelity
and stereo image specificity will result. If not, the stereo image will be constricted and
lack definition. Recording
techniques and audio electronic designs differ with respect to absolute phase. In order
that the end user be able to interconnect an audio system properly, it is important that
manufacturers provide absolute phase information regarding their product. In most cases
it's a simple matter to reverse the wires at each speaker or the phono cartridge.
An excellent description of absolute
phase can be located in the archives section of Galen Carol Audio, San Antonio, Texas.
http://www.gcaudio.com/Archives/absolutepahse.htm
FAQ |
Why
are A.I. preamps phase inverting? |
| Our design philosophy
is based on the basic audio truth "the less in the box - the better the sound". Our exhaustive tests have proven that the
addition of phase inversion stages only adds additional circuitry which complicates
accurate audio signal amplification.
Considering that absolute phase can
be maintained by simply "reversing each speaker connection" we feel that phase
inversion circuitry is unnecessary. FAQ |
How
do A.I.'s "full-function" phono preamps differ from its line stage preamps? |
| Both preamplifier
designs use the same basic parts and circuit topography. However, the
"full-function" Modulus 3a is a pure dual-mono design which insures maximum
separation of circuit componentry thus minimizing channel cross-talk. FAQ |
Will
the Modulus phono preamp work with a low-output cartridge? |
| Yes, but with
reservations. While the preamp’s low noise and overall 58dB of gain is sufficient to
amplify many low-output cartridges we feel there is a general loss of dynamics and low
bass performance. For low-output M/C cartridges, (.1-.8mV), we recommend our M/C Gold
Board option. FAQ |
What
phono cartridges are recommended for use with Modulus preamps? |
| For years Audible
Illusions has gone through considerable effort to poll our dealers, audio reviewers and
end users for their opinions as to which phono cartridges operate best with our
preamplifiers. Periodically we publish our revised listing which is supplied to dealers
and included with every Owner’s Manual. A copy of the current cartridge survey can be
downloaded from our Technical Bulletin section. FAQ |
How
long will the tubes in my preamp last? |
| The Russian
"mil-spec" tubes currently installed in our preamplifiers should last 2-3000
hours or 1-2 years of normal use. However, we are aware that tube filaments are very
fragile and susceptible to rough handling. For this reason, and not to inconvenience our
customers, we include a spare tube with every new preamplifier shipped. FAQ |
When
is it time to change a tube? |
| Assuming there has
been no premature failure or excessive noise you should expect to change your
preamp’s set of tubes after 2 years of normal use. When tubes do fail they make
crackling sounds or ring excessively. Otherwise you should notice a gradual softening of
dynamics and a roll-off of high frequencies. FAQ |
Does
the preamps standby mode extend tube life? |
| During our previous
experience with tube electronics in the recording industry we learned that if the
equipment was left on all of the time maximum circuit stability and tube life was greatly
extended. Other than breakage, nothing is more damaging to the delicate inner parts of a
tube than to apply full current when it is cold. However, minimizing thermal shock by keeping
the filaments on is just a partial solution to extended tube life. It's necessary to
address internal gas build-up and possible poisoning of the cathodes.
In the early 1980's we had perfected
a circuit that we felt would improve tube life. Then, only by manufacturing hundreds of
preamplifiers with and without this special circuit and monitoring tube life were we able
to prove that it works. Subsequently, all Modulus preamplifiers mfg. since 1985 have this
standby, soft-start circuit. FAQ |
Does
removing the top cover from my Modulus preamp improve its sound? |
| Be advised that, to
insure maximum rejection of RF interference, our preamp chassis are constructed completely
of aluminum parts. Removing the top cover would expose the preamps sensitive low-level
circuitry to unwanted noise and hum. We also do not want our owners being exposed to
dangerous high voltage. Please, do not operate your Modulus with its top cover removed!
FAQ |
Is
it OK to remove the phono tubes from my preamp if I only use the line stage? |
| DO
NOT attempt to operate the preamplifier with the phono stage tubes
removed! Doing so will result in excess high voltage on the phono stages’ coupling
caps and could damage the circuit. Also, removal of the phono tubes will substantially
increase the filament voltage on the line stage tubes and will compromise performance and
shorten tube life. FAQ |
What
are the dimensions of the box and its shipping weight? |
| Audible Illusions
preamplifiers are packaged with two boxes, an inner and an outer box. The approximate
dimensions of the outer shipping box are 17"D x 27"L x 8"H. Shipping weight
is 22lbs. FAQ |
Are
upgrades available for older Audible Illusions Preamplifiers? |
| Audible Illusions no
longer modifies/upgrades its older Modulus Series 1, 2 & 3 Preamps due to the fact
that special order of parts to retrofit most models causes production delays. However,
several of our dealers do sell "factory reconditioned" Modulus 3 and 3a preamps.
We now offer a "factory trade-in program". Please contact our customer service
department if interested. FAQ |
PREAMPLIFIERS - MANUFACTURING HISTORY
| 1978-79 |
DUAL MONO Stereo
Preamplifier - $895
Tube compliment 1-12AX7, 2-6DJ8 per channel
|
| 1979-81 |
MINI MITE I Stereo
Preamplifier - $295
Tube compliment 1-12AX7, 2-6DJ8
|
| 1980-81 |
URANUS I Stereo
Preamplifier - $995
Tube compliment 1-12AX7, 2-6DJ8 per channel
|
1982 |
MODULUS Stereo
Preamplifier - $395
Relay turn-on circuitry, tube compliment 1-12AX7, 1-6DJ8, 1-12AU7
|
| 1983 |
URANUS II Stereo
Preamplifier - $1,195
Tube compliment 1-12AX7, 1-6DJ8, 1-12AU7 per channel
|
| 1983-84 |
MODULUS ONE Stereo
Preamplifier - $495
Outboard power transformer, relay turn-on circuitry, tube compliment 3-6DJ8
|
| 1985 |
MODULUS 2 Stereo
Preamplifier - $595
Dual Mono Design, no-feedback line stage, tube compliment 4-6DJ8
|
| 1986 |
MODULUS 2A Stereo
Preamplifier - $695
Upgraded version of Mod 2 w oxygen free copper circuit boards
|
| 1987 |
MODULUS 2B Stereo
Preamplifier - $795
Upgraded version of 2A w FET B+ Power Supply
|
| 1988 |
MODULUS 2C Stereo
Preamplifier - $895
Upgraded version of 2B with Tiffany RCA Jacks, some units with stepped attenuator volume
controls, most had Bourns conductive plastic volume pots
|
| 1989-92 |
MODULUS 2D Stereo
Preamplifier - $995
Upgraded version of 2C
|
| 1993-95 |
MODULUS 3 Stereo
Preamplifier - $1495-$1695
Completely re-designed. Now with outboard power supply
|
| 1994 |
L1 LINE STAGE Stereo
Preamplifier - $1495-$1995
With Class A Headphone Amplifier
|
| 1996-01 |
MODULUS 3A Stereo
Preamplifier - $1895-$2495
Preamplifier has undergone yearly upgrades. Now with stepped attenuator volume controls,
lower impedance circuitry and specialized parts, capacitors, etc.
|
| 2001 |
L2 LINE STAGE Stereo
Preamplifier - $2195
With Remote Control, Surround-Sound Bypass Circuitry
|
|
FAQ |
| PREAMPLIFIER
TUBE REPLACEMENT How often should my tubes be replaced? |
| In the early 1980's
Audible Illusions developed a unique "filament-on circuit" in which preamp tubes
would not be subjected to "thermal shock", a major cause of premature tube
failure. In normal use our factory tested tubes should last minimum of two to three
thousand hours, aprox.1-2 years, of normal use. FAQ |
How
can I tell if a tube is going bad? |
| Unless the tube
develops premature-excessive "hiss, rumble or crackling sound" the only way to
tell is a gradual softening of high frequencies due to normal plate wear. Audible
Illusions recommends that, for optimum sonic performance, Modulus tubes should be changed
a least every 12-18 months. Our preamplifiers designs are based on reasonably-priced 6922
tubes. Quality pre-tested tubes are available from our dealers in the range of $25-$50.
FAQ |
What
are microphonic tubes? |
| All
"factory-supplied" tubes are pre-tested for low-microphonics, (ringing).
However, if in normal use of your preamplifier, any vibration causes a high frequency
ringing or pinging sound to be heard through your speakers, we suggest you replace the
defective tube as soon as possible. Audible Illusions is most aware of the fact that audio tubes are fragile devices
and do not take kindly to rough handling, especially in shipping. In the event of a
damaged tube and to minimize our customer’s inconvenience, we always include a spare
tube with every new preamplifier. FAQ |
Should
my preamplifier's tubes be matched? |
| High performance
preamplifiers should contain tubes matched for low noise and voltage. The Modulus’ no
feedback line stage absolutely must have graded and matched tubes with a recommended
voltage tolerance of +/- 5%. *(Please refer to A.I. Technical Bulletin #2 which explains a
simple technique for grading and matching tubes) FAQ |
What
tubes are recommended for A.I. preamplifiers? |
| Current preamplifier
owners should refer to their owner’s manual or consult with A.I. Dealers authorized
to sell tubes. Additional-related tube data is in our Technical Bulletin #6. Only "mil-spec, low-noise" 6922,
6DJ8, 7308 or European E88CC tubes are recommended for use in Modulus preamplifiers.
Previous production Modulus M2, M3,
M3a and L1 preamplifiers used Russian 6922 tubes. While quality and sonic performance of
these tubes were excellent for several years it is unfortunate that current-production
from the Sovtec/Reflector factory does not have the same sonic identity and a high
percentage prematurely fail.
Current production Modulus M3a and
L2 Preamplifiers use a Russian Military Type 6922 with "Grey Plates" and have
excellent sonics and reliability.
Similar tubes which have different
technical specs should not be used.
7DJ8 tubes require higher filament
voltage and performance is marginal.
6NIP tubes should not be substituted
as they require additional filament current and their use will compromise performance.
FAQ
|
What
are "NOS" tubes? |
| The audio term
"NOS" simply means "New Old Stock". There are several tube suppliers
who purchase tubes, no longer being manufactured, that were considered to be sonically
excellent. Unfortunately, many of these tubes are used and do not meet current performance
specifications. Be advised
that certain older brands of "NOS" tubes should not be used in modern,
high-gain, high-performance preamplifiers like a Modulus. Many of these old type 6DJ8,
7308, E88CC tubes have weak insulators and their internal grids are not wound to close
tolerance. Thus they have unacceptable microphonics, tube hiss and high distortion. FAQ |
What
is "Tube Rolling"? |
| To the best of our
knowledge, this term was first used by our good friend Roger Modjeski of Ram Labs. Roger
truly understands the audiophile's desire to constantly "tweak" his system and
changing various brands of tubes can change the sonic characteristic of a particular piece
of audio equipment. We still proudly display our "tube-rollers society button"
he gave us back in the mid 1980's. Swapping one brand of 6DJ8 for another, particularly with our single-ended
Modulus preamps, can be quite noticeable. However, the sonic difference one perceives is
subjective and many of these tubes do not meet our technical specifications. We recommend
you read our technical bulletin #6 for additional information regarding this subject.
Additional information regarding
audio tubes is published by The Tweak Shop on their website:
www.tweakshop.com/Tube care.html
FAQ |
| AUDIBLE ILLUSIONS
AMPLIFIERS What is the purpose of an amplifier? |
| In order to drive a
speaker to realistic sound levels a quality power amplifier must be used to boost the
low-level signal source with minimal distortion and sonic coloration. FAQ |
Why
are A.I. amplifiers now solid state designs? |
| Quite simply, tube
power amplifiers tend to be problematical and expensive to operate and very few tube
amplifiers perform well at frequency extremes. Audible Illusions also believes in pure Class
A and High Bias Class AB Amplifier circuits to insure maximum performance linearity.
Regrettably there just are no longer any good power tubes being made that can reliably
perform at the high plate voltage required by our push-pull tube designs.
We also accepted the challenge to
manufacture a solid state amplifier that had the midrange dimensionality of tube
amplifiers but also have bass control, dynamic contrasts, superior damping factor, low
distortion and transparent sound. FAQ |
Why
does A.I. use both Bipolar and FET devices in their designs? Aren't FETS better? |
| Audible Illusions
employs both Bipolar and FET transistors in its amplifier designs each to optimum effect. High Speed Bipolar transistors are used
exclusively in driver and output stages as these devices exhibit superior dynamics and
current handling ability.
We believe Field Effect Transistors,
"FETS", are best suited for certain low-noise audio applications and MOSFETS
best suited for discrete power supply circuits. FAQ |
What is the difference between Class A and Class AB operation? |
| Class A amplifiers,
either push-pull or single-ended designs, have their idle bias set very high. This insures
the output devices are operating in optimum linearity. This high bias also insures minimum
distortion. Be advised that many Class A amplifiers run hot due to inadequate heat sink
design. The massive heat sinks of Audible Illusions’ amplifiers insure that they only
operate "warm-to-the touch". Class AB amplifiers operate in push-pull mode. This means that, for each
complimentary pair of output devices, one device pushes the positive top half of the sine
wave while the other device pulls the negative half. Properly designed, there must also be
sufficient bias to insure that the amplifier operates at low volume in Class A mode to at
least 10% of its rated output .
Audible Illusions Class AB
amplifiers are also biased to insure that neither complimentary pair of output devices are
turned off. This technique eliminates crossover distortion.
An excellent comparison of Class A
and Class AB operation is described by our UK dealer, Walrus Audio. www.walrus.co.uk/tech/tech.htm FAQ |
Do A.I.
amplifiers run hot? |
| Audible Illusions
amplifiers run "warm-to-the-touch" due to their high-bias circuitry. However,
massive heat sinks and protection circuitry prohibits overheating. FAQ |
How well do A.I. amplifiers handle low-impedance speakers? |
| Our amplifiers are
"high-current" designs and double their power into lower impedance loads.
Another important consideration is their stability into speakers with highly reactive
impedance curves. FAQ |
Are
A.I. amplifiers "bridged designs"? |
| Absolutely Not. Almost
all audio speakers have non-linear impedance curves and require a stable power amplifier.
Typically, bridged amplifiers lack the current drive and stability necessary to handle
complex speaker loads. FAQ |
What
is the recommended break-in period? |
| Audible Illusions
amplifiers require a 2-3 week break-in period. Further refinement to the sound will
continue for a considerable time. FAQ |
What
are the dimensions of the shipping box and approximate weight? |
| All of our amplifiers
are "Double Boxed". The
shipping weight of our M150 Mono Amplifier is 85 lbs. The dimensions of the outer carton
are 20"W x 30"L x 16"H.
The shipping weight of our M175 Mono
Amplifier is 75 lbs. and the dimensions of the outer carton are 20"W x 30"L
x16"H. FAQ |
AMPLIFIERS - MANUFACTURING HISTORY
| 1979-81 |
MINI-MITE II STEREO
TUBE AMPLIFIER - 45wpc, Class AB, $695
Tube compliment 1-12AX7, 1-6CG7, 2-EL34 per channel
|
| 1980-81 |
M-80 MONO TUBE
AMPLIFIER - 80w, Class AB, $995 each
Tube compliment 1-12AX7, 2-6CG7, 4-6550
|
| 1982-83 |
S-50 STEREO TUBE
AMPLIFIER - 50wpc, Class AB, $995
Successor to Mini-Mite II, amplifier has larger power transformer, 1st voltage amp. and
re-styled faceplate. Tube compliment 1-12AT7, 1-6CG7, 2-EL34 per channel
|
| 1983-84 |
M-80 MONO TUBE
AMPLIFIER - 80w, Class AB1, $1495 each
Successor to previous M-80 with larger transformers, filament supply and re-styled
faceplate. Tube compliment 1-12AX7, 2-6CG7, 4-KT88
|
| 1988-91 |
S120 STEREO, SOLID
STATE AMPLIFIER - 120wpc $1495
A.I.’s first solid state design.
|
| 1992-97 |
S120A STEREO SOLID
STATE AMPLIFIER - 120wpc $1795
Successor to S120. Amplifier has regulated relay circuitry, larger driver boards with
higher speed transistors, re-styled faceplate etc.
|
| 1998-00 |
S120B STEREO SOLID
STATE AMPLIFIER - 120wpc $2795
Successor to S120A, Redesigned FET driver circuitry, re-styled faceplate
|
| 1998-01 |
M150 MONO SOLID STATE
AMPLIFIER - 150w, Class A, $6,495 per pair
Regulated Relay & Driver Circuitry w Choke Input. Single-ended or balanced inputs.
|
| 2001 |
M175 MONO SOLID STATE
AMPLIFIER - 175W, Class AB1, $4,995 per pair
Regulated Relay & Driver Circuitry.
|
|
FAQ |
PRODUCT UPGRADES
Product upgrades for older products
are no longer available other than normal repair and maintenance for A.I. amplifiers and
preamplifiers. Factory Exchange Program is
now available for older model Modulus Series 3 and 3a preamplifiers. (Please contact A.I.
Customer Service for details)
FACTORY SERVICE-
Warranty and Repairs of A.I. Products
Warranty service is performed, free
of charge, for parts and labor for all A.I. products for a period of 2 years from date of
purchase. *(Please read warranty agreement)
Warranty Period for tubes is 90 days
from date of purchase.
Factory Service/Repairs of A.I.
products no longer covered by warranty is charged at rate of $75 per hour, (1-hr min.)
plus parts and return shipping.
OWNER’S MANUALS
Manuals for "current
production" products may be purchased from Audible Illusions for $15 each.
Photocopies of manuals for older products are $20 each. Your request and payment should be
mailed to Audible Illusions, PO Box 8, Pleasanton, CA 94566. |
