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Description of Item:
5th generation design, now at Revision E.  This is the premier and only Phase Linear PL14 or PL20 Universal Control Board Upgrade kit available. It is a professional-class upgrade product, meticulously engineered to look and perform better than the original.  Professional grade, "UNIVERSAL" PL14A/B + PL20 main audio board Upgrade Assembly to enhance the quality of the components, circuit design and PCB on existing Phase Linear 400 and 700B amplifiers - direct drop in kit for PL14 A & B, PL20 and PL36 equipped amps (the vast majority of all Phase Linear amplifiers).  Design flexibility allows you to build it out as "stock Quasi-Complementary" or "enhanced Full-Complementary" by populating the component options you desire.  Swap out the original single-sided PCB with a premium double-sided, silk screened and solder masked circuit board.  Upgrade to high quality, low noise, metal film, precision resistors and improved audio grade Wima polypropylene and Cornell Dubilier (CDE) Mica (audio path) and Nichicon MUSE electrolytic capacitors  (power supply segments only) throughout.  Significantly improve the signal integrity of your amplifier while keeping the Phase Linear sound that you love.

Do you own a Phase Linear 400 Series 1 or 700B Amplifier (the ones with the 2 big VU meters)? They are great amplifiers but the original control board is aging and possibly not providing you the best possible sound performance anymore or has become intermittent and unreliable. Here is your opportunity to replace the original control board with a high quality, premium component equipped replacement and bring your favorite Phase Linear amp back to better than its original glory.   The complete kit and assembled boards use Wima Polypropylene and Cornell Dubilier Mica non-polar capacitors and Nichicon MUSE audio grade electrolytic polar capacitors to replace the original ceramic and aluminum electrolytic types and precision 1%, low noise metal film resistors throughout to replace the original carbon film types.  All discrete semiconductors are premium ON Semiconductor devices.  Kits and complete assemblies are provided with precision matched front end for low output offset.

This product is offered in Complete Kit and Fully Assembled configurations.  One Option is available as well, the Phoenix Contact Screw Terminal Connector kit.  These are orderable on the White Oak Audio Design eStore.

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 original single-sided PL-14 or PL-20 PCB. The replacement PCB is 0.062 inch thick double sided circuit board with plated through holes and white epoxy silkscreen legends 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 locations to secure it in the amplifier. This replacement board includes holes to securely attach the amplifier wire connections to the PL14_20 Control board rather than the original backside only solder connection used by Phase Linear. This feature can be seen pictured in the photo. The original wire attachment points would often separate from the PCB, ruining the board.

Complete Kit Configuration (PL14_20 - KIT)
This is a brand new, upgrade blank PCB kit to replace the original control board (PL14A or B or PL20) with a premium grade replacement. This kit includes the bare board and all electronic, heat sink and hardware components.   Assembly instructions and documentation will be provided electronically upon purchase. The components in the kit are pre-formed for you.  The components you receive in the kit may differ slightly in appearance from those pictured due to parts manufacturer changes.

You will get what you see installed on the PCB in the picture above:
  •  Brand new upgrade blank PCB to replace the original PL14 or PL20 PCB
  • All 1/4 and 1/2W 1% metal film resistors
  • All 3W 1% metal film resistors
  • All potentiometers as high quality Cermet type
  • All non-polar capacitors as Wima Polypropylene (higher value NP caps) or as Cornell Dubilier Mica (lower value NP caps)
  • All polar capacitors as Nichicon MUSE audio grade electrolytics
  • All Diodes (ON Semi)
  • All Transistors (ON Semi)
  • Premium, precision Burr Brown (TI) SoundPlus Audio Op Amp for the front end amplifier.
  • All voltage regulator ICs
  • All Aavid transistor heatsinks and transistor insulators
  • All hardware
  • Solid Copper Bus wire and Teflon tubing to allow tying power and ground for both channels together when used without White Oak Audio Backplane Kits.
Detailed photographs, assembly parts list and "crystal clear" assembly and installation instructions will be provided to you at time of purchase.
This kit is rated as ADVANCED.  This upgrade kit is for skilled technicians. Building and installation of this kit is more advanced than the several other White Oak Audio Design kits.  The installer should be familiar and comfortable with working on electronic equipment and using a soldering station and associated tools. Ensure good control of soldering iron temperature, not exceeding 600 degrees F, so the PC Board and components are not ruined by excessive heat. 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 assembly and installation for you. Complete kits and fully assembled versions of this PL14_20 control board are available on the White Oak eStore.

Fully Assembled Configuration (PL14_20 - ASSY)
As above in the Kit but professionally assembled by White Oak Audio Design.  Ready to install in your amplifier.

Phoenix Contact Screw Terminal Connector Option (CONN-OPTION)
This option allows the PL14_20 Assembly to be installed in the Phase Linear chassis using screw terminal compression clamping of the wires that attach to the bottom edge of the card instead of by soldering.  This option includes 2 - 13 pin connector strips (main connections), 2 - 3 pin connector strips (BIAS transistor connection).

Photos of the finished project are shown below (installed in chassis, installed in chassis with original PL14 PCBA component side showing for comparison, installed in chassis with original PL14 PCBA solder side showing for comparison, complete kit contents).
This kit is sold AS-NEW with no returns (due to potential damage to the circuit board once assembly has begun).

Shipping Weight:
16 oz. for Complete Kit or Assembly
White Oak Audio will pay USPS Small Flat Rate Box Priority Mail shipping charges (but not insurance) worldwide for Complete Kits and Complete Assemblies. When ordering from the eStore, select the proper ship to location to suit your destination.  If you require other than this shipping service, buyer will be responsible for shipping charges by method selected on the shipping weight stated above. If you do not pay for shipping insurance, delivery will be made totally at buyer's risk for loss and damage.

Your purchase will be professionally and neatly packaged for shipment within the standard USPS Small Flat Rate Box. International orders are welcome.

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