YORKVILLE Audiopro 3000 Owner's Manual
O WNERS MANU AL / GUIDE D' OPERATION
INTRODUCTION
Your new Yorkville Audiopro 3000 power amplifier is designed and built to provide
years of trouble free performance. We believe it to be the best high power amplifier you
can buy at any price.
Up to now, owning a high power, high efficiency amplifier meant that you had to sacrifice
sonic quality. With Yorkville’s 3000 design, we have overcome this problem. The 3000
weighs a comfortable but solid 40 pounds, fits into two rack spaces, runs at near digital
efficiency, reproduces music with over 4000 Watts of headroom, draws all the power
it needs from a standard AC outlet, and has excellent distortion and noise specifications. It will drive reactive, phase shifted loads with no difficulty, and yet it is fully
protected from accidental short circuits. Our design goal was to create an amplifier
which would do exactly what an amplifier should do: reproduce music with great power,
complete reliability, and complete signal fidelity. We think you will agree that the
Yorkville 3000 does exactly that.
We hope this manual will provide the answers to the questions you may have about the
particular characteristics of this amplifier.
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ENERGY
MANAGEMENT
SYSTEM
All amplifiers with ratings above 1400 watts rely on the fact that the average power
required to reproduce music is considerably below the maximum power the amplifier
is capable of providing. Some amplifiers are capable of actually delivering their rated
power continuously, but these may consume as much as 50 amperes in doing so. To
get around this problem, many high power amplifiers are shipped with either a special
high current plug on the line cord or with two line cords. In practice, the user is often
forced to find some way to connect these products to standard line outlets. Due to the
lower average power required by music, this will sometimes work, but there is the
possibility that circuit breakers in the concert hall will trip in the middle of a performance.
The AUDIOPRO 3000 is internally capable of delivering its rated power on a continuous
basis. However, rather than leaving the question of energy management to chance, the
AUDIOPRO 3000 incorporates active energy management circuitry which continuously
monitors the actual power consumed from the AC line. Should that exceed an average
of 12 amperes over a sustained period, the AUDIOPRO 3000 will reduce its output
power and therefore its power consumption accordingly. The reduction required is
very small: A drop in output power of 3 dB will reduce the power consumption to below
12 amperes in even the most extreme cases. Under prolonged actual tests with
continuous and compressed music driving two ohm speaker loads connected to each
channel, the AUDIOPRO 3000 consumed less than 10 amperes on average, and the
energy management circuit was never activated. (This performance is due in large
measure to the high efficiency of the AUDIOPRO 3000’s output circuitry: Other
amplifiers draw considerably more power under identical conditions!) It is nice to know
that an AUDIOPRO 3000 will probably never cause a nuisance trip of a breaker.
INPUTS and
SWITCHES
MONO/STEREO
The AUDIOPRO 3000 is a high efficiency amplifier which is capable of delivering a
greater percentage of its input power to the speaker load than most other amplifiers.
Under actual operating conditions its power conversion efficiency approaches that of
digital switching amplifiers. However, digital switching amps are still plagued by poor
specifications and cumbersome operating constraints. The AUDIOPRO 3000 provides
the superior transient response and low distortion figures associated with the best and
most reliable analog designs.
The AUDIOPRO 3000 accepts either balanced or unbalanced inputs. Either XLR or
PHONE cords may be used. XLR cords are normally used for balanced operation.
However, stereo PHONE cords may also be used. Internally, the AUDIOPRO 3000
inputs are simply wired in parallel: The TIP of the channel “A” PHONE input is
connected to pin 2 of its XLR input, the RING is connected to pin 3, and the SLEEVE is
connected to PIN 1.
This switch simply connects the inputs of channel “A” directly to the inputs of channel
“B”. A signal connected to either channel thus is routed to both amplifiers. Fig,#2- 2
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DAISY CHAINING
GROUND STRAP
BRIDGED OPERATION
In large installations it is often necessary to operate many amplifiers in parallel. Several
AUDIOPRO 3000 may be paralleled by patching from the unused input jack of the first
amp to the second amp’s input, and so on down the line. The original source must drive
all of the amplifiers. Eighteen AUDIOPRO 3000 channels would present a load of about
600 Ohms. Any source capable of driving a 600 Ohm line to +15 dBm should be able
to drive this load with no problem.
For best results, daisy chaining should be done with balanced patch cords. Ground
loop hum can be eliminated by lifting the ground straps of all but the first amplifier in the
chain.
Removing the ground strap on the rear panel will decouple chassis ground from circuit
ground. Safety (“earth”) ground is still connected to the chassis. We do not
recommend lifting the ground strap unless you are experiencing problems with ground
loop hum in multiple amplifier setups where lifting the ground straps of all but one
amplifier cures the hum problem. Caution: Sometimes hum problems are an indication
of improper AC wiring somewhere else in your system. Don’t just doctor the symptom
by lifting grounds: Fix the cause by making sure that the proper electrical wiring safety
regulations have been adhered to.
Historically, bridged mode operation was a means of getting high power from medium
power amplifiers. The AUDIOPRO 3000 delivers more power from one channel than
most other amps deliver when fully bridged. Bridging the AUDIOPRO 3000 will
reproduce music with a headroom of about 4500 Watts into a 4 ohm load! We don’t
know of any subwoofers that can handle such power. We recommend that you
carefully check the ratings of your speaker system against the power specifications
listed in this manual before you consider bridging the AUDIOPRO 3000.
We have purposefully made it a little difficult to bridge the AUDIOPRO 3000. You need
to construct a special crossed-phase balanced cable. If your input cable is a balanced
XLR, you will need a stereo phone cable with the ring connection of one end going to
the tip of the other end, and the ring of that end going to the tip of the first end. If your
input cable is a phone plug, then you need to make an XLR patch cord with pin 2 of one
end going to pin 3 of the other, and pin 3 of that end going to pin 2 of the first end. See
Fig, #3. Connect the special cable from channel “A” to channel “B”. Connect the input
to your AUDIOPRO 3000 to channel “A”. Put the STEREO/MONO switch in STEREO
position. Connect your speaker between the two RED binding posts. (The resulting
phase polarity is marked on the panel).
You MUST set both front panel gain controls to the same position for bridged operation
to work properly. Failure to do this will result in premature current limiting and will
produce less power than is produced in non bridged mode's.
Again a word of CAUTION: Yorkville’s own high power speaker systems have circuit
breaker protection built in. Although they may shut down, they are unlikely to be
damaged by a bridged AUDIOPRO 3000. However, many other speaker manufacturers make high power cabinets with no protection features whatsoever. Yorkville Sound
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LTD. is not responsible for any damage which may result as a consequence of
exceeding such a speaker’s power handling capability. In any case, Yorkville’s two year
unconditional warranty does not cover any consequential damages to other equipment. Please consider these facts carefully before you choose to run your AUDIOPRO
3000 in bridged mode.
SUBSONIC FILTER
PROTECT L.E.D.
The AUDIOPRO 3000 features a specially designed subsonic filter which effectively
transfers the wasted energy from the band below 30 Hz to the band between 35 and
70 Hz. The filter provides an 18 dB/Oct skirt below 40 Hz and a 3.6 dB boost at 50 Hz.
This is achieved with a five pole network designed to minimize phase shift down to 40
Hz. We recommend using this filter in conjunction with most subwoofers and with high
power full range cabinets. Engaging this filter immediately produces the perception of
a better “bottom end”, while excessive and possibly damaging excursions of the
speaker cone are restrained. See Fig, #2- 1
The PROTECT LED will glow steadily if the Energy Management System is activated.
In the event of a shorted load or a load which is of too low an impedance for the amplifier
to handle, (less than 2 ohms), the PROTECT LED will flash alternately on and off at
about one second intervals. The sound may come on and off at the same rate. In this
case, the fault in the speakers or the speaker cables should be located and remedied.
No reset of the AUDIOPRO 3000 is required to restore proper operation.
The AUDIOPRO 3000 is fully protected against all possible passive load conditions. It
can operate with a “dead” short continuously without damage. The output stage uses
a unique triple slope VI limiting scheme which is sophisticated enough to remain inert
during transient currents in excess of 100 amperes and phase angles of more than 45
degrees, yet is capable of protecting the output stage from damage due to accidental
short circuits and improper loads. (You may have read that current limiting can affect
the sound of an amplifier. Our answer to this is that it only gets in the way of the sound
if it is not done properly. In the AUDIOPRO 3000, its done right!)
DC PROTECTION
CLIP L.E.D.'S
OTHER DESIGN
DETAILS
In the unlikely event of the AUDIOPRO 3000 outputs “going DC”, a thyristor circuit will
short the output and divert all potentially harmful currents away from your speakers.
The CLIP LEDS on the front panel are of the pulse stretching type. Any excursion
beyond the dynamic headroom of the amplifier - no matter how short - is trapped and
converted into a visible pulse of light.
The AUDIOPRO 3000 represents a significant advance in the art and science of analog
power amplifier design. It incorporates MOSFETS where they should be used - in the
driver stage where their immunity from secondary breakdown lets them reliably drive
bi-polar output devices which can present an essentially capacitive load at high
frequencies. The unique design of the output stage uses four supply voltages. This
greatly reduces internal power dissipation. Rather than switching between the various
supply voltages, the AUDIOPRO 3000 smoothly directs its output stage to the appropriate supply. The output is free of the “glitches” that plague other multiple supply
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designs. In fact, due to the proprietary design of the power output section, the
discontinuities visible on the distortion analysis product are much smaller than those
normally associated with crossover distortion in single supply class AB designs. These
circuit advances are clearly reflected in the superior specifications of the AUDIOPRO
3000. The AUDIOPRO 3000 may be the first high power amplifier to offer specifications
and sonic performance equal to or surpassing ultra low distortion designs such as
class-A amplifiers.
RELIABILITY
APPLICATIONS
The AUDIOPRO 3000 is designed and manufactured by Yorkville Sound LTD. Each
unit undergoes a thorough, temperature cycled burn-in period, and each circuit is
tested by both manual and sophisticated computer controlled equipment which is
capable of identifying any deviation from the design center parameters. The design of
the AUDIOPRO 3000 is radical in concept but conservative with respect to the power
handling capabilities of the output devices. The topology guarantees that thermal
stress - not secondary breakdown - will set the limits of operation, while the computer
optimized heat dissipation system insures that excessive thermal stress will not occur.
Yorkville’s reputation as a manufacturer of reliable equipment will be further enhanced
by the AUDIOPRO 3000.
The AUDIOPRO 3000 was designed primarily for high power applications. It excels
at driving big systems and subwoofers to their maximum SPL, and its rugged, roadworthy construction ensures that it will keep on doing just that - from location to location
for years to come.
The AUDIOPRO 3000 is not only suitable for use in both heavy duty touring sound
reinforcement systems but also when high headroom and ultra-low distortion are
needed to fully reproduce the dynamic range and clarity of today’s CD recordings. This
last point needs emphasis: The AUDIOPRO 3000 will drive 8 Ohm loads with better
sonic purity and lower distortion than any “listening amplifier” we know of, including
those that cost much much more. And, since the AUDIOPRO 3000 is built to survive
grueling road conditions and constant 2 ohm operation, its reliability in a fixed
installation running 4 or 8 ohm studio monitors is without parallel.
Of course, what really counts is how it sounds. Listeners have commented that the
AUDIOPRO 3000 provides the clearest most transparent reproduction they have ever
heard. You will have to judge for yourself.
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SPECIFICATIONS
POWER:
All values are in WATTS at 1KHz, except FTC 20Hz-20KHz.
Measurements made with regulated 120 VAC sine wave at line cord.
All values are rounded down to the nearest 25 watts.
BURST AVG.
Measured as a 2 cycle burst at 1KHz, 8:1 duty.
(Continuous measurements may require line currents >15 Amps)
ONE CHANNEL DRIVEN (WATTS)
LOAD CONT, AVG,. BURST AVG PEAK INSTANT FTC 20-20KHz
8 ohms 550 650 1500 475
4 ohms 900 1250 3000 800
2 ohms 1500 2250 6000 1200
BOTH CHANNELS DRIVEN (WATTS)
LOAD CONT, AVG,. BURST AVG PEAK INSTANT FTC 20-20KHz
8 ohms 475 625 1500 425
4 ohms 750 1200 3000 650
2 ohms 1200 2175 6000 950
BRIDGED (WATTS)
LOAD CONT, AVG,. BURST AVG PEAK INSTANT FTC 20-20KHz
16 ohms 925 1225 3000 850
8 ohm 1500 2400 6000 1300
4 ohms 2400 4350 12000 1900
THD DISTORTION: ( measured at 1 dB below rated power, BW = 80 KHz )
LOAD AT 1 KHz 20 Hz - 20 KHz
8 ohms < 0.003 % < 0.04 %
4 ohms < 0.004 % < 0.05 %
2 ohms < 0.008 % < 0.06 %
CROSS TALK: -75 dB below full power at 1KHz,
-60 dB below full power, 20 Hz - 20 KHz.
INPUT IMPEDANCE: 20K ohms balanced, 10 Kohms unbalanced.
INPUT SENSITIVITY: 1.4 VRMS sine wave = full power. ( 36 dB gain )
CMRR (bal input): >31 dB 20 Hz - 20 KHz
CONTROLS: Rotary gain, MONO sw, special subsonic filter sw.
DISPLAYS: 2x CLIP, 2x ACTIVITY, PROTECT, POWER ON. (LEDS)
FREQUENCY RESPONSE
Within 1dB, 20 Hz to 20 KHz, (50 Hz boost sw out)
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HUM AND NOISE: -105 dB below max output RMS voltage, unweighted.
DC OFFSET: Less than 25 millivolts.
PROTECTION: Fully protected: DC, LOAD and THERMAL.
COOLING: Interleaved heatsink with DC servo controlled fan.
SLEW RATE: Power amp: 30 V/usec, 60 V/usec in bridged mode.
(rise time limited to 18 V/usec by input filter).
DAMPING FACTOR: > 500, 20 Hz - 400 Hz, into 8 ohms.
MAX OUTPUT CURRENT:
` 100 amperes for 10 milliseconds, 50 amperes contin.
TURN ON/OFF: < 15 milliwatt / seconds, 0.5 Wpk. (1s on delay)
EFFICIENCY: Better than 75% at full power into 4 Ohms.
WEIGHT: 40 pounds. 17.75 Kilograms.
SIZE: 3.5" x 19" x 15.75 (front panel to binding posts)
POWER SUPPLY: Toroidal transformer, 82,000 uF filter caps, combination
power switch/circuit breaker.
POWER CONSUMPTION:
Will not exceed 13.5 Amps under actual conditions.
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