Variax Guitar Replacement Battery Cable (RVP-1)

RVP-1 Replacement Battery Cable with "built-in" Reverse Voltage Protection for your “1st Generation” Line6© Variax™ Guitar

(Battery Cable Replacement)

For the “1st Generation” Variax™ Guitar Models (300/500/600/700), primary power is supplied through an internal battery. Power is supplied to the Main Printed Circuit Board (MPCB) via a cable that incorporates a “9V Battery Snap” connection at one end to connect the battery, and a “JST-PH2” connector on the other end to connect to the MPCB. Battery Power is sourced from either a standard 9V battery or a cartridge that holds 6 standard AA batteries. The cartridge connects to the Battery Snap exactly the same way as a 9V battery. It is this connection (battery to Battery Snap) that can lead to catastrophic “Reverse Voltage” conditions that will damage your “1st Generation” Variax™ Guitar.

 H & H Guitars has developed a “Reverse Voltage Protection” device (RVP-1) that is incorporated into a replacement cable for the OEM battery connection. This results in a replacement cable (for damaged OEM cables) that also acts as primary protection to the internal circuits of your “1st Generation” Variax™ Guitar. Also, as the RVP-1 is designed as a replacement for the OEM battery cable in any “1st Generation” Variax™ Guitar, it is longer than the OEM cable and can make exchanging the battery or cartridge significantly easier as a result.

Description

If the power source to the MPCB is reversed (even for a short period of time) a bad thing will happen; the current from the battery will flow in reverse through a diode on the MPCB and potentially destroy the diode. This results in an “open circuit” that will prevent normal power from reaching the MPCB until this diode is replaced. Since this diode is a “surface-mount device” (SMD), it is not easily sourced or replaced without specific information and specialized equipment.

This can (and frequently does) occur as easily as briefly touching the “Battery Snap” to the battery or cartridge with the connectors misaligned (backward). There is nothing inside the “1st Generation” Variax™ Guitars to prevent this “Reverse Voltage” condition.

In the RVP-1, we incorporated a PMOSFET reverse voltage protection circuit into the “Battery Snap” connector that is very efficient to protect “1st Generation” Variax™ Guitars from reverse polarity related damages. The circuit acts as a battery polarity protection circuit. Our design team believes that the best way to design a reverse polarity protection circuit is by incorporating a simple P-MOSFET, because PMOS cuts off the positive rail and the “reversed” circuit will not get any voltage.

Installation

Note: This procedure may be considered difficult if one is not familiar with basic lutherie procedures and common electric guitar construction. If this is your case, H & H Guitars recommends taking the guitar (along with the RVP-1) to your technician for installation.

Installing the RVP-1 is as simple as replacing the OEM power cable. As previously stated, one end of this cable is located inside the Battery Compartment, and the other end attaches to the MPCB inside the guitar. As anyone who is familiar with “1st Generation” Variax™ guitars knows, some models are harder than others to access the MPCB, but some make it as easy as removing a rear cover on the guitar. Detailed instructions are included with each purchase.