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Description of Item:
This is the premier Phase Linear PL 400 LED Lightboard upgrade kit on the web. It is a professional-class upgrade product, meticulously engineered to look and perform better than the original.
  • 3 separate jumper or switched meter sensitivity settings
  • Adjustable Meter illumination level
Do you own a Phase Linear 400 Series 1 Amplifier (the one with the 2 big VU meters)? It is a great amplifier but maintaining the original incandescent meter light bulbs that frequently burn out can be a real nuisance, Here is your opportunity to replace the original light board with a high-quality, long-life LED powered replacement.

This is a brand new, upgrade assembly to replace the original incandescent light bulb board (PL18A) with a long life, low power, LED based board assembly.
You get what you see in the pictures above (except for the DPDT toggle switch shown in the 4th and 5th pictures).  The 18" wire whips to wire in the switch are provided, but the switch is up to you to choose.  A recommendation is E-Switch Part Number 100DP3T1B1M1QEH but the choice is up to you.

The light board allows you to select the meter sensistivity that you desire with 3 settings.  The settings are:

  • 0 dB (half as sensitive as the stock PL board setting)  100W = 0dB reading on the meter scale.
  • -6dB (same sensitivity as the stock PL board setting)  50W = 0dB reading on the meter scale.
  • -20dB (5x as sensitive as the stock PL board setting)  10W = odB reading on the meter scale.,
These settings can be accomplished by either:
  • Installing the 2 jumpers in the appropriate position on the 3 pin headers, or

  • Using the optional wire whip and a switch kit (purchased separately)
In addition to the light board assembly, you will receive:
  • 4 - 6-32 hex nuts
  • 4 - Tyraps to neaten up the wiring harness
  • 12 - #6 Nylon washers to correctly space the height of your assembly within your meters (there is some variability in the meters over the years that Phase Linear was in production

An optional wire whip and switch kit is available if you desire to mount an externally accessible switch to control the meter sensitivity.  This kit includes:

  • 2 - 18" red-white-black wire whips with 3 position connectors to connect the attenuation control switch to the LED Light Board
  • 1 - three position toggle switch to mount in the chassis rear (above the RCA input jacks and below the 4 output binding posts is the most common mounting location - requires drilling one 1/4" diameter hole in chassis to mount switch)

There are 4 ultra-bright, wide dispersion LEDs for each meter providing a consistent wash of light for meter illumination. You can choose warm-white, clear white or blue LEDs for your application depending on which LEDs you specify.

The LEDs are powered with a forward current of up to 18mA to provide bright, pleasing illumination while reducing the power requirements by over 80% from the original board. A single potentiometer allows you to control the illumination intensity of all the LEDs to your desired effect.

A bridge rectifier plus an adjustable low drop out voltage regulator (LDO) are located in the center of the board surrounded on the left and right with 2 filter capacitors. This combination provides a smooth DC source for the LEDs. The cool running LEDs eliminate the heat associated with the original equipment incandescent bulbs and last indefinitely. No more replacing those hard to find bulbs and no more discoloration of the meter plastic due to the excessive heat from the incandescent bulbs.

The printed circuit board is a high quality FR-4 based, epoxy-glass PCB with HASL tin/lead plating on the solder pad areas replacing the cheap original single sided PL-18A PCB. The replacement PCB is 0.062 inch thick double sided circuit board with plated through holes and white epoxy silkscreen legending on the component side and green solder mask on both sides. It is a direct drop in for the original board size, using the original mounting hardware to secure it in the amplifier. This replacement board includes holes to secure and strain relieve the amplifier wire connections to the LED Light board. This feature can be seen pictured in the photos. The original PL18A wire attachment points would often separate from the PCB, ruining the board.

This upgrade kit is for skilled technicians. You can see from the pictures, no soldering is required.  All wiring connects to the convenient 5 position terminal block using a small screwdriver.  Each wire terminal location is nicely labeled in the board silkscreen.  While installation is not a difficult procedure, the installer should be familiar and comfortable with working on electronic equipment and using associated tools.  If you are not familiar with working on electronic equipment or do not possess the proper equipment, it is recommended that you take your amplifier to a service technician that can perform the LED Light Board Upgrade and installation for you.

Photos of the finished project are shown below (installed in chassis, front view with BLUE water clear LEDs, front view with BLUE diffused LEDs, front view with WHITE water clear LEDs, component side of the finished assembly, solder side of the finished assembly).
This kit is sold AS-NEW with no returns.

Ship From Zip Code: 01564
Shipping Weight: 12 oz.
Your purchase will be professionally and neatly packaged for shipment. International orders are welcome

Shipping charges are not included and will be computed based on your 'ship to' location (please provide a ZIP code for USA addresses and your complete address if an international destination).

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