The AMG PRA went beyond being a transparent preamp
with 1M Ohm input. A user-selectable 4 stage “Active Low
Frequency and Harmonic Gain” control gave it distinctive
characteristics to enhance the speaker performance, a
world-first in preamp design.
AMG PRA
USER’S MANUAL
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Table of Contents
FCC Notice - Declaration of Conformity Information .................................................................... 2
EU Declaration of Conformity ...................................................................................................... 3
Safety Instructions ....................................................................................................................... 4
Introduction ................................................................................................................................. 7
Specifications .............................................................................................................................. 8
NuPrime’s Limited Warranty and Limitation of Liabilities .......................................................... 10
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FCC Notice - Declaration of Conformity Information
This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference in a residential installation. This equipment uses and can radiate
radio frequency energy and, if not installed and used in accordance with the instructions, may
cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular installation. If this
equipment does cause harmful interference to radio or television reception, which can be
determined by turning the equipment o and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
• Consult the dealer or an experienced radio/TV technician for help.
WARNING: Only peripherals complying with the FCC class B limits may be attached to this
equipment.
Changes or modifications made to this equipment, not expressly approved by us or parties
authorized by us could void the user’s authority to operate the equipment. This device complies
with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device
may not cause harmful interference, and (2) this device must accept any interference received,
including interference that may cause undesired operation.
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EU Declaration of Conformity
Hereby, NuPrime Audio, Inc. declares that this device is in compliance with the essential
requirements and other relevant provisions of Directive 2004/108/EC.
The manufacturer of this product is NuPrime Audio, Inc., 1712 Pioneer Ave. Ste 1817, Cheyenne,
Wyoming 82001, USA.
The Authorized Representative for EMC and product safety is NuPrime Audio, Inc., 1712 Pioneer
Ave. Ste 1817, Cheyenne, Wyoming 82001, USA.
For any service or guarantee matters please refer to the addresses given in separate service or
guarantee documents.
For Customers in Europe
Disposal of Old Electrical & Electronic Equipment (Applicable in the European
Union and other European countries with separate collection systems)
This symbol on the product or on its packaging indicates that this product shall
not be treated as household waste. Instead it shall be handed over to the
applicable collection point for the recycling of electrical and electronic
equipment. By ensuring this product is disposed of correctly, you will help
prevent potential negative consequences for the environment and human health,
which could otherwise be caused by inappropriate waste handling of this product.
The recycling of materials will help to conserve natural resources. For more detailed information
about recycling of this product, please contact your local Civic Office, your household waste
disposal service or the shop where you purchased the product.
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Safety Instructions
There are two categories of Safety Instructions included in this manual:
• Product Warnings, (i.e., what must never be done to assure avoiding those hazards that
• could cause bodily injury or property damage); and
• User Directions (i.e., what must always be done to assure the safe use of your device).
The Safety Instructions contained in this manual have been categorized in accordance with the
seriousness of the potential hazards through the use of Signal Words. Those Signal Words, and
their intended meanings, are as follows:
DANGER: Indicates that a failure to observe the Safety Instructions could result in death or
catastrophic bodily injury.
WARNING: Indicates that a failure to observe the Safety Instructions could result in serious
bodily injury.
CAUTION: Indicates that a failure to observe the Safety Instructions could result in minor bodily
injury or property damage.
NOTE: Designates important information that relates to activities and/or conditions that might
result in loss of data and/or damage to your device.
Safe Use and Operation of Your Device
This equipment emits stray RF energy and will interfere with the reception of signals by airborne
electronic navigational devices or medical devices. Do not operate this equipment near any
sensitive medical devices.
WARNING: Use only grounded AC power cords.
Always immediately disconnect the power to the equipment in the event the device emits an
unusual odor or sound or generates smoke.
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WARNING: Never attempt to disassemble, repair or make any modification to your device.
Disassembly, modification or any attempt at repair could cause bodily injury or property damage,
as well as damage to the device itself.
WARNING: Your device is not a toy. Never allow children to play with your device. Misuse, rough
or improper handling of your device by children could result in serious bodily injury for any of the
enumerated safety warnings in this manual. In addition, always keep all accessories and
components out of the reach of small children as small parts might present a choking hazard.
Seek immediate medical attention if choking occurs or if any small part has been swallowed.
CAUTION: Never raise the sound volume level too high when using your device with earphones.
An excessive sound volume level could cause damage to your hearing.
WARNING: To reduce the risk of re or electric shock, do not expose the unit to moisture or
water.
Do not allow foreign objects to get into the enclosure. If the unit is exposed to moisture, or a
foreign object gets into the enclosure, immediately disconnect the power cord from the wall.
Take the unit to a qualified service person for inspection and necessary repairs.
Read all the instructions before connecting or operating the component.
Keep this manual so you can refer to these safety instructions.
Heed all warnings and safety information in these instructions and on the product itself. Follow
all operating instructions.
Do not use this unit near water.
You must allow a minimum 10 cm or 4 inches of unobstructed clearance around the unit.
Do not place the unit on a bed, sofa, rug, or similar surface that could block the ventilation
openings. If the unit is placed in a bookcase or cabinet, there must be ventilation of the cabinet to
allow proper cooling.
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Keep the component away from radiators, heat registers, stoves, or any other appliance that
produces heat.
The unit must be connected to a power supply only of the type and voltage speci ed on the rear
panel. Connect the component to the power outlet only with the supplied power supply cable or
an exact equivalent. Do not modify the supplied cable.
Do not route the power cord where it will be crushed, pinched, bent, exposed to heat, or
damaged in any way. Pay particular attention to the power cord at the plug and where the cord
exits the back of the unit.
The power cord should be unplugged from the wall outlet during a lightning storm or if the unit is
to be left unused for a long period of time.
Immediately stop using the component and have it inspected and/or serviced by a quali ed
service agency if:
• The power supply cord or plug has been damaged.
• Objects have fallen or liquid has been spilled into the unit.
• The unit has been exposed to rain.
• The unit shows signs of improper operation.
• The unit has been dropped or damaged in any way
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Introduction
The design goal for AMG PRA was to deliver a transparent sounding analog preamp with its
distinctive characteristics. Several new design concepts were developed and used in the AMG PRA
besides 1MΩ input impedance to achieve the best analog inputs.
Users of smallish speakers would often detect a distinct drop in bass response with some audio
tracks. Instead of a simple “Bass Boost” function that lifts a targeted low-frequency band, a user-
selectable 4 stage “Active Low Frequency and Harmonic Gain” control compensates for the lack of
bass presence. It achieves some bass extension and a more natural roll-off.
Additional features such as the 2 stage gain control and invertible phase control increase the
compatibility of the AMG PRA with other power amplifiers.
The ultra-wide bandwidth low noise JFET input feeds the latest generation of NuPrime’s “Single-
Ended, Non-Negative Feedback” Class A module and MUSES8920 Op-amp input amplification
stage. This circuitry produces harmonics similar to vacuum tube amps, which has an “airy and
velvety” sound.
The layout of the AMG PRA takes excellent care in isolating the sensitive audio signals from the
power circuitry. The power circuitry comprising of a star topology power and ground layers is built
on one board while a separate board houses the pre-amplification circuit. An isolation layer
separates these two boards, which further minimizes interference. The effect is a highly
transparent sound that is natural and not over etched.
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Specifications
• Frequency Response: 10Hz to 200kHz; +-0 to -0.1dB
• THD: 0.008 %
• Input Impedance:
o Balanced IN: 1M Ohm @ 10 Hz ~ 200 kHz
o Line IN: 1M Ohm @ 10 Hz ~ 200K Hz
• Rated Output Voltage: 2 V (LINE) / 4V (BAL) @ 100 Ohm
• S/N: 95 dB
• Loudness Compensation:
o 2.2 dB (125 Hz)
o 4.5 dB (100 Hz)
o 5.3 dB (75 Hz)
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• Gain : 3.2 (High) / 2.1 (Low)
• Dimensions: 235 mm W x 300 mm D x 55 mm H (including feet)
• Weight: 2.5 Kg
• Worldwide AC voltage: (90VAC~130VAC // 210VAC~ 250VAC) With Voltage Select Switch
• AC Fuse: Slow-blow, 1A, 250VA
AC Inlet Voltage Selector:
Make sure that the AC Voltage selector switch at the bottom of the unit is switched to the
appropriate voltage for your country. All AMG series are shipped with the switch set to 230V AC
in order to prevent accidental damage.
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NuPrime’s Limited Warranty and Limitation of Liabilities
ADDITIONAL RIGHTS
For consumers, who are covered by consumer protection laws or regulations in their country of
purchase or, if different, their country of residence, the benefits conferred by this warranty are in
addition to all rights and remedies conveyed by such consumer protection laws and regulations.
This warranty does not exclude, limit or suspend any rights of consumers arising out of
nonconformity with a sales contract. Some countries, states and provinces do not allow the
exclusion or limitation of incidental or consequential damages or allow limitations on how long an
implied warranty or condition may last, so the limitations or exclusions described below may not
apply to you. This warranty gives you specific legal rights, and you may also have other rights that
vary by country, state or province. This limited warranty is governed by and construed under the
laws of the country in which the product purchase took place.
LIMITED WARRANTY
For a period of TWO (2) YEARS from the date of retail purchase by the original end-user
purchaser (“Warranty Period”), NuPrime warrants (in) this product against defects in materials
and workmanship, and (ii) that each Product, unmodified and under normal use and conditions,
will substantially comply with NuPrime’ applicable written technical documentation for the
Product. NuPrime reserves the right to make substitutions and modifications from time to time
in the specifications of Products sold by NuPrime, provided that such substitutions or
modifications do not materially affect overall Product performance.
If a hardware defect exists and a valid claim is received within the Warranty Period, at its option
and to the extent permitted by law, NuPrime will (1) repair the hardware defect at no charge,
using new or refurbished replacement parts, (2) exchange the product with a product that is new
or which has been manufactured from new or serviceable used parts and is at least functionally
equivalent to the original product, or (3) refund the purchase price of the product. NuPrime may
request that you replace defective parts with user-installable new or refurbished parts that
NuPrime provides in fulfillment of its warranty obligation. A replacement product/part assumes
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the remaining warranty of the original product or ninety (90) days from the date of replacement
or repair, whichever provides longer coverage for you. When a product or part is exchanged, any
replacement item becomes your property and the replaced item becomes NuPrime's property.
When a refund is given, your product becomes NuPrime's property.
OBTAINING WARRANTY SERVICE
If you purchased the product in the U.S., deliver the product, at your expense, to any NuPrime
Service Center located in the U.S. If you purchased the product outside of the U.S., deliver the
product to any NuPrime Authorized Importer in the country where you purchased the product.
Be aware, however, that not all countries have NuPrime Authorized Service Providers (‘NASP’)
and not all Authorized Service Providers outside the country of purchase have all parts or
replacement units for the product. If the product cannot be repaired or replaced in the country it
is in, it may need to be sent to a different country or returned to the country of purchase at your
expense for repair or replacement. If you seek service in a country that is not the country of
original purchase, you will comply with all applicable import and export laws and regulations and
be responsible for all custom duties, V.A.T. and other associated taxes and charges. Where
international service is available, NuPrime may repair or exchange defective products and parts
with comparable products and parts that comply with local standards.
You can always deliver the product to NuPrime’s U.S.A or Taiwan service center for obtaining
warranty service, however, you may have to pay for shipping cost.
NuPrime may send you user-installable new or refurbished replacement product or parts to
enable you to service or exchange your own product (“DIY Service”). Upon receipt of the
replacement product or part, the original product or part becomes the property of NuPrime and
you agree to follow instructions, including, if required, arranging the return of original product or
part to NuPrime in a timely manner.
When providing DIY Service requiring the return of the original product or part, NuPrime may
require a credit card authorization as security for the retail price of the replacement product or
part and applicable shipping costs. If you follow instructions, NuPrime will cancel the credit card
authorization, so you will not be charged for the product or part and shipping costs. If you fail to
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return the replaced product or part as instructed or the replaced product or part is not eligible for
warranty service, NuPrime will charge the credit card for the authorized amount.
EXCLUSIONS AND LIMITATIONS
This Limited Warranty applies only to hardware products manufactured by or for NuPrime that
can be identified by the "NuPrime" trademark, trade name, or logo affixed to them. The Limited
Warranty does not apply to any non-NuPrime hardware products or any accessories, even if
packaged or sold with NuPrime hardware. Non-NuPrime manufacturers, suppliers, may provide
their own warranties. Other accessories distributed by NuPrime under the NuPrime brand name
are not covered under this Limited Warranty. This warranty does not apply: (a) to damage
caused by accident, abuse, misuse, misapplication, liquid contact, fire, earthquake, non-NuPrime
products, or other external causes; (b) to damage caused by service performed by anyone who is
not a NASP; (c) to a product or a part that has been modified without the written permission of
NuPrime; (d) to consumable parts, such as batteries, or protective coatings designed to diminish
over time unless failure has occurred due to a defect in materials or workmanship; (e) to cosmetic
damage, including but not limited to scratches, dents, and broken plastic on ports; (f) to defects
caused by normal wear and tear or otherwise due to the normal aging of the product; or (g) if any
NuPrime serial number has been removed or defaced.
Important: Do not open the hardware product. Opening the hardware product may cause
damage that is not covered by this warranty. Only NuPrime or a NASP should perform service on
this hardware product.
This warranty and remedies set forth above are exclusive and in lieu of all other warranties,
remedies and conditions, whether oral or written, express or implied. NuPrime specifically
disclaims any and all implied warranties, including, without limitation, warranties of
merchantability and fitness for a particular purpose. If NuPrime cannot lawfully disclaim implied
warranties under this limited warranty, all such warranties, including warranties of
merchantability and fitness for a particular purpose are limited in duration to the duration of this
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warranty. No NuPrime reseller, agent, or employee is authorized to make any modification,
extension, or addition to this warranty.
NuPrime is not responsible for direct, special, incidental or consequential damages resulting from
any breach of warranty or condition, or under any other legal theory, including but not limited to
lost profits, downtime, goodwill, damage to or replacement of equipment and property, any
costs of recovering, reprogramming, or reproducing any program or data stored in or used with
NuPrime products, and any failure to maintain the confidentiality of data stored on the product.
NuPrime specifically does not represent that it will be able to repair any product under this
warranty or make a product exchange without risk to or loss of programs or data.
Some states and provinces do not allow the exclusion or limitation of incidental or consequential
damages or exclusions or limitations on the duration of implied warranties or conditions, so the
above limitations or exclusions may not apply to you. This warranty gives you specific legal
rights, and you may also have other rights that vary by state or province.
Proof of purchase in the form of a bill of sale or receipted invoice which is evidence that the unit is
within the Warranty period must be presented to obtain warranty service.
Replacement as provided under this warranty is the exclusive remedy of the consumer. Nuprime
shall not be liable for any incidental or consequential damages for breach of any express or
implied warranty on this product. Except to the extent prohibited by applicable law, any implied
warranty of merchantability or fitness for a particular purpose on this product is limited in
duration to the duration of this warranty.
