APHEX JPRE 500 Jensen Transformer Coupled Mic Pre Module Owner’s Manual
- June 13, 2024
- APHEX
Table of Contents
APHEX JPRE 500 Jensen Transformer Coupled Mic Pre Module Owner’s Manual
SAFETY DECLARATIONS
WARNING
SHOCK HAZARD DO NOT OPEN
AVIS: RISQUE DE CHOC ELECTRIQUE NE PAS OUVIR
PREVENT FIRE OR SHOCK HAZARD DO NOT EXPOSE THIS DEVICE TO RAIN OR MOISTURE. DO NOT REMOVE THE COVER. NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL ONLY.
CAUTION: For continued protection against risk of fire, replace only with the same type and rating of fuse.
WARNING: Do not place objects containing liquid on this unit as it is not designed to protect against spillage. Do not expose this unit to dripping or splashing of liquids as the unit is not designed to protect against these occurances.
WARNING: This unit must be connected to a mains socket outlet with a protective earthing connection.
WARNING: The J PRE 500 has been tested and meets the FCC, CE and European Union rules, regulations, and guidlines for use. Do not attempt to modify or change the J PRE 500, as this could void the regulatory compliance, which would place you at risk of losing your authority to operate the J PRE 500.
WARNING: Do not place objects on top of this unit if they weigh more than 10 pounds.
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 generates, 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 off 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.
INSTALLING THE J PRE 500 IN A 500 SERIES RACK
- Turn off and unplug your 500 series rack frame. Inspect the card slot you intend you use to make sure that it is clean and free of any debris.
- Before removing your J PRE 500 from its box, discharge any static electricity buildup you may have by touching your 500 series rack.
- Pull your J PRE 500 module out of its box and carefully slide it into place in the designated opening. Sight down the back of the module (use a flashlight if necessary) and ensure the card edge connector is aligned to seat into the card slot of the frame.
- Firmly and evenly push the J PRE 500 module into place until its is positively seated in the card slot.
- Use the 2 thumb screws in the module to mount the J PRE 500 front panel to the 500 series rack. These screws have a pretty tight fit; please be careful not to cross thread.
- Plug your 500 series rack back into the AC source and power up your rack. Your J PRE 500 will automatically power up with your 500 series rack.
INTRODUCTION
The J PRE 500 mic pre is inspired by the Aphex flagship 1788A preamp. They both use the same Jensen JT11K8 nickel input Transformer. Both preamps also feature the Aphex patented Mic Lim limiter which limits before the preamp. Unlike the 1788A, the J PRE 500 also features a Jensen JT-11DL nickel output transformer for output balancing. This provides the cleanest possible balanced output signal
CONTROLS & INDICATORS
TRIM CONTROL
The Trim control boosts the input signal from +26dB to +65dB.
INPUT METER
This 20 segment input meter provides visual confirmation of the input signal
level. The top three LEDs of the meter are red. When the input signal reaches
the top red LED, the input signal wil clip.
OUTPUT LEVEL SWITCH
The output level can be set to +16dB, +20dB and +24dB. You will need to know
the maximum input level of the next device in the audio chain to set this
properly. Most professional audio devices can handle a +24db input signal
without issue.
However, some inexpensive computer audio interfaces have a maximum input level of less than +16dB. Most also offer a -20dB pad to address these kind of issues.
-26dB PAD
When the input signal is clipping the preamp with the input trim control
turned all the way down, the -26dB pad can be engaged to provide more
headroom.
PHASE
The Phase button will invert the input signal 180 degrees. Using two
microphones on the same source can cause phase problems.
Reversing the phase of one of the microphone signals will often clear up the issue.
75Hz HIGH PASS FILTER
Engaging the 75Hz HPF will roll off all the freqencies below 75Hz at
18dB/octave. It’s a good idea to use the HPF when recording voices or
instruments that don’t have much low frequency content. Only capturing the
relevant frequencies will provide a cleaner mix later on.
48V PHANTOM POWER
Condenser microphones require power to function. Sometimes a microphone will use internal batteries, but usually the required power is provided by the mic pre. Turning on the Phantom Power will send power through the cable to power the microphone. Be carefull though, as ribon microphones and some older dynamic microphones can be damaged or destroyed by phantom power.
MIC LIM
Pressing this button will engage the Aphex patented MIC LIM limiter. It limits before the preamp. This way a large transient signal will be limited before it is amplified. This protects the mic pre and provides a cleaner signal than standard limiters. When the Mic Lim is limit- ing, the Mic Lim button will flash red.
INSTRUMENT INPUT
The J PRE 500 provides a 1/4”, 10 MOhm instrument input. When an instrument is plugged in to this input it will override the XLR input on the receiving frame. This input makes it easy to record guitar and bass tracks with the J PRE 500.
APHEX is a member of the API Audio VPR Alliance.
The J PRE 500 is a VPR approved module.
SERVICE & WARRANTY
LIMITED WARRANTY
PERIOD
One year from date of purchase
SCOPE
All defects in workmanship and materials. The following are not covered:
a. Voltage conversions
b. Units on which the serial number has been defaced, modified, or
removed
c. Damage or deterioration:
- Resulting from installation and/or removal of the unit.
- Resulting from accident, misuse, abuse, neglect, unauthorized product modification or failure to follow instructions contained in the User’s Manual.
- Resulting from repair or attempted repair by anyone not authorized by Aphex Systems.
- Occurring from shipping (claims must be presented to shipper).
WHO IS PROTECTED
This warranty will be enforceable by the original purchaser and by any
subsequent owner(s) during the warranty period, so long as a copy of the
original Bill of Sale is submitted whenever warranty service is required.
WHAT WE WILL PAY FOR
We will pay for all labor and material expenses for covered items. We will pay
return shipping charges if the repairs are covered by the warranty.
LIMITATION OF WARRANTY
No warranty is made, either expressed or implied, as to the merchantability
and fitness for any particular purpose. Any and all warranties are limited to
the duration of the warranty stated above.
EXCLUSION OF CERTAIN DAMAGES
Aphex Systems’ liability for any defective unit is limited to the repair or
replacement of said unit, at our option, and shall not include damages of any
other kind, whether incidental, consequential, or otherwise.
Some States do not allow limitations on how long an implied warranty lasts and/or do not allow the exclusion or limitation of incidental or consequential damages, so the above limitations and exclusions may not apply to you.
This warranty gives you specific legal rights, and you may also have other rights which vary from State to State.
SERVICE INFORMATION
If it becomes necessary to return this unit for repair, you must first contact Aphex for a Return Authorization (RMA number), which will need to be included with your shipment for proper identification. If available, repack this unit in its original carton and packing material. Otherwise, pack the equipment in a strong carton containing at least 2 inches of padding on all sides. Be sure the unit cannot shift around inside the carton. Include a letter explaining the symptoms and/or defect(s). Be sure to reference the RMA number in your letter and mark the RMA number on the outside of the carton. If you believe the problem should be covered under the terms of the warranty, you must also include proof of purchase. Insure your shipment and send it to:
APHEX
3500 N. San Fernando Blvd. Burbank, CA. 91505 USA PH: 818.767.2929 FAX:
818.767.2641
SPECIFICATIONS
OPERATING LEVEL
Switch Setting +4dBu
INPUT
- Type: Transformer less, active balanced
- Impedance: 40KΩ
- Unbalanced: 20KΩ
- Nominal Level: +4dBu
- Maximum Level: +24dBu
- CMRR: >40dB
OUTPUT
- Impedance: 110Ω
- Nominal Level: +4dBu
- Maximum Level: +24dBu Unloaded
AUDIO
- Frequency Response: +0.5dB 10Hz-38KHz
- Dynamic Range: 120dB
- THD: 10Hz – 22kHz @ max output,
- IMD: .0003% 10Hz – 22kHz 0 max output, .0007%
CONNECTOR PINOUT
- CHASSIS GROUND
- OUTPUT + (+4 LEVEL)
- (unused)
- OUTPUT – (+4 LEVEL)
- COMMON
- (unused)
- (unused)
- INPUT- (+4 LEVEL)
- (unused)
- NPUT+ (+4 LEVEL)
- (unused)
- +16VDC
- POWER SUPPLY COMMON
- -16VDC
- (unused)
This product is protected under one or more of the following Aphex patents.
6,266,423
3500 N San Fernando Blvd. Burbank, CA 91505 USA
PH: 818.767.2929 FAX: 818.767.2641
www.APHEX.com
References
- Aphex | Products for Professional Audio, Recording, Broadcast, Audio Applications
- Manual-Hub.com – Free PDF manuals!