AMCRON GEODYNE Professional Power Amplifier Owner’s Manual
- June 9, 2024
- AMCRON
Table of Contents
AMCRON GEODYNE Professional Power Amplifier
PROFESSIONAL POWER AMPLIFIER OWNER’S MANUAL
@1992 by Crown International, Inc.
P.O. Box 1000
Elkhart, IN 46515-1000
AMCRON is a division of Crown International, Inc.
GEODYNE'” is a trademark and Amcron”‘, JOG®, and ODEP”‘ are registered
trademarks of Crown International, Inc.
FULL THREE-YEAR WARRANTY ****
SUMMARY OF WARRANTY
AMCRON, a division of Crown International, Ine.. I718 West Mishawaka Road.
Elkhart, Indiana U.S.A. 46517-4095 warrants to you, the ORIGINAL purchase and
ANY SUBSEQUENT OWNER of each NEW Amcron product. for a period of three 3)
years from the date of purchase by the original purchaser (the “warranty
period”) that he knew Amcron product is Iree of defects in materials and
workmanship. and we further warrant the new Amcron product regardless of the
reason for failure, except as excluded 1 this Amcron Warranty
ITEMS EXCLUDED FROM THIS AMCRON WARRANTY
This Amcron Warranty is in effect only for failure of a new Amcron product
which occurred within the Warranty Period. It does not cover any product which
has been damaged because of any intentional misuse, accident, negligence, or
loss which Is covered under any of your insurance contracts. This Amcron
Warranty also does not extend to the ew Amcron product it the serial number
has been defaced, altered, or removed.
WHAT WILL THE WARRANTOR DO
We will renedy any defect. regardless of the reason for failure (except as
excluded), by repair, replacement, or refund. We may not clect a refund unless
you agree, or unless ve are unable to provide a replacement, and repair is not
practical or cannot be timely made. If a refund is elected, then you must make
the defective or malfunctioning product available to us Iree and clear of all
iens or other encumbrances. The refund will be equal to the actual purchase
price, not including interest, insurance, closing costs, and other finance
charges less a reasonable deprecation on the product Irom the date of original
purchase. Warranty work can only be performed at our authorized service
centers. We will remedy the defect and ship the product from the service
center within a reasonable time after receipt of the defective product at our
authorized service center. All expenses n remedying the defect, including
surface shipping costs to the nearest authorized service center, will be borme
by us. (You must bear the expense of all taxes. duties, and other customs fees
when transporting the product.)
HOW TO OBTAIN WARRANTY SERVICE
You must noty us ot your need for warranty service not later than ninety
(0) days after the expiration of the warranty period. All components must be
shipped in a factory pack. Corrective action will be taken within a reasonable
time of the date ol receipt of the defective product our authorized service
center. If the repairs made by our authorized service center are not
satisfactory, notify our authorized service center immediately.
DISCLAIMER OF CONSEQUENTIAL AND INCIDENTAL DAMAGES
YOUARENOTENTITLED TO COVER FROM US ANY INCIDENTAL DAMAGES RESULTING FROM
ANY DEFECT IN THE NEW AMCRON PRODUCT. THIS INCLUDES ANY DAMAGE TO ANOTHER
PRODUCT OR PRODUCTS RESULTING FROM SUCH A DEFECT.
WARRANTY ALTERATIONS
No person has the authority to enlarge, amend, or modify this Amcron Warranty.
This Amcron Warranty is not extended by the length of time you are deprived of
the use of the new Ameron product. Repairs and replacement parts provided
under the terms of this Amcron Warranty shall carry only the unexpired portion
of this Amcron Wamanty.
DESIGN CHANGES
We reserve the nght to change the design of amy prxtact from tinme to time
without notice and with no obligation to make corresypending changes in
products previously manufactured
LEGAL REMEDIES OF PURCHASER
Ne action to enforce this Amcron Warranty shall be commenced later than ninety
(90) days after expiration of the warranty period.
THIS STATEMENT OF WARRANTY SUPERSEDES ANY OTHERS
CONTAINED IN THIS MANUAL FOR AMCRON PRODUCTS.
Amcron, P.O. Box 1000, 1718 W. Mishawaka Rd., Elkhart, Indiana U.S.A.
46515-1000. Telephone: 219/294-8000. Facsimile: 219/294-8346.
CAUTION
RISK OF ELECTRIC SHOCK -DO NOT OPEN.
- NO USER SERVICEABLE PARTS INSIDE.
- REFER SERVICING TO QUALIFIED PERSONNEL.
WARNING
TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT
TO RAIN OR MOISTURE!
Welcome
Congratulations on your purchase of an Amcron GEODYNE'” amplifier. The
GEODYNE I and IT are compact, professional stereo power amplifiers that are
engineered to meet the demanding sound reinforcement needs of the performing
musician. GEODYNE amplifiers compare very favorably to amplifiers costing much
more, providing clean sound and high signal-to-noise ratio.
This manual will help you successfully install and use your amplifier-we
strongly recommend you read all the instructions, warnings and cautions
contained within. If you plan to operate in one of the two MONO modes be sure
to read the Mono section. Also, for your protection, please save your bill of
sale since it is your official proof of purchase.
Unpacking
Please inspect your new amplifier for any damage that may have occurred during transit. If damage is found, notify the transportation company immediately. Only you may initiate a claim with the carrier for damage resulting during shipment. Even if the unit arrived in perfect condition, as most do, save all packing materials so you will have them if you ever need to transport the unit. NEYE R SHIP THE UNIT WITHOUT THE FACTORY PACK.
Features
- Full, uncoloured stereo power into a wide variety of loads.
- BRIDGE MONO or PARALLEL MONO operation provides optimum performance for high or low impedance mono loads.
- Patented ODEP® circuitry keeps amplifier running under adverse conditions without risk of damage.
- Unique heatsink/forced air cooling system dissipates heat rapidly to protect your investment and provide greater power.
- Triple input sensitivity switch can be set to 1.4 V,
- 775 V, or a fixed voltage gain of 26 dB.
- Full protection against sho1ted outputs, open circuits, mismatched loads, overheating, RF burnout, input DC, and input overload.
- Front panel power switch/circuit breaker.
- Front panel /OC® indicator.
- Tum on delay protects load against transients. 0 Fault protection circuit shuts off power supply in the rare event abnormal current is detected in output circuits.
- Full three year “No-Fault” warranty.
Installation
Always remove power from the unit and turn the input level controls fully
counterclockwise while making connections. This will eliminate any chance of
loud blasts damaging loudspeakers.
Follow the guidelines listed below, together with the specific steps required
for the mode of operation which you intend to use:
-
Install the unit in a standard 48.3 cm equipment rack or place it on a stable surface. Mounting dimensions: 48.3 cm wide, 8.9 cm tall, and 40.6 cm deep behind rack “ears.”
IMPORTANT! Allow for adequate ventilation and DO NOT BLOCK THE AIR VENTS. -
Use high-quality loudspeaker cables between the load and the output binding posts on the rear panel. Banana plugs are recommended at the amplifier end.
-
Use shielded cables to connect the output of your mixer to the inputs of the amplifier. Either balanced (tip, ring, sleeve) or unbalanced (tip, sleeve) 6.3 mm phone plugs can be used.
-
Amplifier usable at any AC voltage from I 00-240, ±10%, at 50 or 60 Hz, depending on internal settings. Your amplifier comes pre-configured for your country’s voltage. Should it be necessary to change the line voltage setting, contact the nearest Amcron Service Center.
Stereo
- Tum the level controls fully counterclockwise and tum off the amplifier.
- Set rear panel switch to STEREO. (Remove PARALLEL MONO jumper if present.)
- Connect the input and output cables as shown in the first example in Figure 3.
- Tum on the amplifier and independently adjust the level of each channel with its respective level control on the front panel.
CAUTION: In stereo mode, never parallel the two outputs by directly tying them together or parallel them with the output of any other amplifier.
Mono
The mono operating modes provide twice the power to one channel as the STEREO
mode. In BRIDGE MONO, the outputs are wired in series for twice the output
voltage. In PARALLEL MONO, the outputs are paralleled for greater current
capacity.
BRIDGE MONO mode is provided for loads with an impedance greater than 4 ohms.
PARALLEL MONO mode should be used for loads of 4 ohms or less.
BRIDGE MONO
- Turn the level controls fully counterclockwise and tum off the amplifier.
- Set rear panel switch to BRIDGE MONO. (Remove PARALLEL MONO jumper if present.)
- Connect the input and output cables as shown in the second example in Figure 3. Use only the Ch. I input and level control.
- Make sure the load is balanced (neither side shorted to ground) and do not use the black(-) binding posts.
- Turn on the amplifier and adjust the level using only the Ch. I level control on the front panel.
PARALLEL MONO
- Turn the level controls fully counterclockwise and turn off the amplifier.
- Set rear panel switch to PARALLEL MONO.
- Install a jumper (at least 1.5 mm2, solid) across the output between the two red ( +) binding posts.
- Connect the input and output cables as shown in the third example in Figure 3. Use Q!!!.y the Ch. I input.
- Turn on the amplifier and adjust the level using Q!!!.y the Ch. 1 level control on the front panel.
- In PARALLEL MONO mode, it is normal for the CH 2 IOC light to glow.
CAUTION: When wired for PARALLEL MONO mode, do not attempt to operate the
amplifier in STEREO or BRIDGE MONO mode until the output jumper is removed.
Failure to do so will result in inefficient operation, distortion and
excessive heating.
Load Protection
To protect your loudspeakers, you may want to put a fuse in series with each
loudspeaker cable. The fuse may be single (fusing the overall system) or
multiple (with one fuse on each driver). See Figure 4 for the correct fuse
size:
Example : A -Choose the peak music power that you want the loudspeaker to receive (in our example, 75 watts). B – Find the loudspeaker impedance (8 ohms). C- Draw a line between points A and B. The value of the fuse is found where this line crosses the middle scale (1.5 amps).
Input Sensitivity Adjustment
An input sensitivity switch is located inside the amplifier and was factory set to a sensitivity of 1.4 V. If your mixer output voltage is not 1.4 V, the GEODYNE sensitivity can be changed to 0.775 V or a voltage gain of 26 dB as follows:
- Tum off and unplug the amplifier from the AC source.
- Remove the top cover.
- Locate the access hole for the sensitivity switch, identified by a label.
- Set the switch to the desired position.
- Replace the top cover.
OPERATION
Precautions
Your amplifier is protected from external faults; however, the following
safety precautions are advised:
-
There are important differences in each of the three operating modes (STEREO, BRIDGE MONO and PARALLEL MONO). Refer to the preceding Installation section.
-
WARNING : Before changing the position of the Stereo-Mono switch, turn the amplifier off.
-
CAUTION: In PARALLEL MONO mode, a jumper is used between the red banana posts
(amplifier outputs). Be sure to remove this jumper for BRIDGE MONO or STEREO mode; otherwise inefficient operation, high distortion and excessive heating wiJI definitely occur. Also, check the Stereo-Mono switch for proper position. -
Use care when making connections, selecting signal sources and controlling the output level. The loudspeakers you save may be your own.
-
Do not short the ground lead of an output cable to the input signal ground. This may form a ground loop and cause oscillations.
-
Operate the amplifier from AC mains of not more than 10% variation above or below the selected line volt.age and only at the specified line frequency.
-
Never connect the output to a power supply output, battery or power main.
-
Circuit tampering by unqualified personnel, or making unauthorised circuit changes voids the warranty .
Remember: Amcron is not liable for any damage resulting from overdriving other components in your system.
Protection
The GEODYNE is protected against all common hazards that plague high-power
amplifiers, including shorted, open or mismatched loads; overloaded power
supplies; excessive temperature, chain destruction phenomena, input overload
damage, and high frequency blowups. The unit protects loudspeakers from DC in
the input signal and from tum on transients. It also protects against unwanted
DC on the outputs. An “Output Device Emulator Protection” (ODEP®) circuit
simulates the internal characteristics of the output transistors. The
amplifier can then detect and compensate for overheating and overload. If
umeasonable operating conditions occur, the protection circuitry limits the
drive level to protect the output transistor stages, particularly in the case
of elevated temperature. Controlled slew rate voltage amplifiers protect
against RF burnouts. Input overloads are stopped at the input to limit
current. The GEODYNE engineers have added still another protection scheme. In
the rare event of an output power transistor failure, your loads are protected
by the “Fault Protection” electronics. This circuit detects abnormally high
instantaneous currents in the output circuits and immediately removes the
power supply energy.
The front panel power switch/resettable circuit breaker along with a thermal
switch imbedded in the windings of the power transformer protect the power
supplies against overload. If the transformer overheats, the thermal switch
shuts off automatically, waits until the unit has cooled to a safe temperature
and then resets itself.
Fuse Replacement
TI1e GEODYNE low energy power supply does use an internal fuse for protection against catastrophic failure. You should never have a need to replace this fuse. In the rare event that this fuse blows, refer the amplifier to yow· Amcron service agent.
Cleaning
A dust filter is provided on the air intake to the cooling system. If this filter becomes clogged, the unit will not cool as efficiently as it should and may produce lower tllan normal output levels due to high heat sink temperature. To clean, remove the filter grille (3 phillips head screws). Use mild dishwashing detergent and warm water for best cleaning. New filters may be ordered from the factory. Dust filters are not I 00% efficient–over the long term this will require that the internal heatsinks be cleaned by a qualified technician. Internal cleaning information is available from your nearest service center.
Service
Your amplifier has very sophisticated circuitry which should only be serviced
by a fully trained technician:
CAUTION : TO PREVENT ELECTRIC SHOCK DO NOT OPEN. NO USER SERVICEABLE
PARTS INSIDE. REFER SERVICING TO A QUALIFIED TECHNICIAN.
Service may be obtained from an authorised Amcron Service Center. (Contact
your local Amcron representative or our office for a I ist of authorised
service centers.) Simply present your bill of sale as proof of purchase along
witll tlle defective unit to an authorized Amcron Service Center to obtain
service. They will handle the necessary paperwork and repair. Remember to
transport your unit in the original factory page
Amcron will pay the SUJface shipping costs both ways fur warranty service to
the authorized service center nearest you after receiving copies of all
shipping receipts. You must bear tlle expense of all taxes, duties, and
customs fees when transporting the unit.
Specifications
Amcron specifications are guaranteed for three years. Further, because our in- house specs arc more stringent than our published specs, every Amcron amplifier will exceed its published specs. All specifications apply to both GEODYNE I and II except where noted.
PERFORMANCE
Note: Measurements made in Stereo, both channels driven into 8 Q
- Frequency Response: ±0.1 dB from 20 Hz to20kHzat I watt.
- Phase Response: ±10° from 10 Hz to 20 kHz at l watt.
Hum and Noise:
- GEO DYNE I: At 26 dB gain, better than 100 dB below (20 Hz to 20 kHz) 220 W.
- GEODYNEII : At26 dB gain, betterthan I00dB below (20 Hz to 20 kHz) 320 W.
Total Harmonic Distortion (THO):
- GEO DY EI: <0.05% from 20 Hz to I kHz, increasing linearly to 0.1 % at 20 kHz at 200 W continuous average power into 8 Q.
- GEO DY E Il :<0.05% from 20 Hz to 1 kHz, increasing linearly to 0.1 % at 20 kHz at 310 W continuous average power into 8 Q.
I.M. Distortion:
- GEODYNE I : <0.05%from JO milliwatts to200W at26dB gain.
- GEODYNEII : <0.05%from 10milliwattsto310W at26dB gain.
- Slew Rate : >13 V per microsecond.
Power
- Output Power : (Max. average power at 1 kHz with 0.1 % THD.)
- GEODYNE I: Stereo-300 W/channel into 4 ohms, 220 W/ channel into 8 ohms, both channels driven.
- Bridge Mono-575 W into 8 ohms, 435 W into 16 ohms.
- Parallel Mono-575 W into 2 ohms, 435 W into 4 ohms.
- GEODYNE II : Stereo-400 W/channel into 4 ohms, 320 W/ channel into 8 ohms, both channels driven.
- Bridge Mono-965 W into 8 ohms, 680 W into 16 ohms.
- Parallel Mono-955 W into 2 ohms, 680W into 4 ohms.
- Load Impedance : Rated for 16, 8, 4, 2 ohm use. Safe with all types of loads, even reactive ones.
- AC Requirements: Available for use at 100, 120, 220/230 and 240 V AC, 50/60 Hz.
- AC Connector: Market specific three wire grounded connector.
CONTROLS/INDICATORS
- Controls: Front panel-A push on/off power switch/circuit breaker; also, a signal level control for each channel. Back panel -A three position switch which selects Stereo, Bridge Mono, or Parallel Mono mode. Inside the amplifier, a three position switch selects l.4 V, 0.775 V, or 26 dB voltage gai11 input sensitivity. Indicators: Red Enable indicator shows on/off status of low voltage power supply. Yellow IOC indicator for each channel ts if distortion of any kind exceeds 0.05%
INOUT/ OUTPUT
- Input Impedance: Nominally 20 K ohms, balanced, and 10 K ohms, unbalanced.
- Connectors : Inputs -balanced 6.3 mm phone jacks. Outputs -colour-coded5-waybindingpostsonl9mmcenters;spaced 19mmapa.tt.I
CONSTRUCTION
Black splatter coat steel chassis with specially designed flow through the
ventilation system.
-
Dimensions: 48.3 cm wide, 8.9 cm high, 40.6 cm deep behind r font mounting surface.
-
Weight: GEODYNE I 13.6 kg
GEODYNE II 14.5 kg -
Mounting: Standard EIA 310 front panel rack mount with suppo1ts for supplemental rear corner mounting.
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