Embedded Files
Adding Reverb, an Effects Loop, and Bias Control to a 5F6A Bassman
Adding Reverb, an Effects Loop, and Bias Control to a 5F6A Bassman
The 5F6A Bassman is a wonderful amp, but let's face it, features like reverb, an effects loop and bias control would be great additions and make the amp more useful. The Amp-Aid ReverbFX3 module adds all these features in a package specifically designed for the 5F6A chassis-- without drilling additional holes. Whether used alone, or in combination with the BMTrem2 module, it converts any 5F6A into a much more flexible and capable amplifier.
The 5F6A Bassman is a wonderful amp, but let's face it, features like reverb, an effects loop and bias control would be great additions and make the amp more useful. The Amp-Aid ReverbFX3 module adds all these features in a package specifically designed for the 5F6A chassis-- without drilling additional holes. Whether used alone, or in combination with the BMTrem2 module, it converts any 5F6A into a much more flexible and capable amplifier.
What is the Amp-Aid ReverbFX3 module?
What is the Amp-Aid ReverbFX3 module?
Amp-Aid is proud to offer the ReverbFX3 module. Designed and optimized for the 5F6A circuit and chassis, the module mounts within the chassis by re-purposing the four speaker jack holes. Chassis rewiring is minimal. In addition to power and ground, only 2 wires insert the module into the existing Bassman signal path. Installation is straightforward and described in detail below.
Amp-Aid is proud to offer the ReverbFX3 module. Designed and optimized for the 5F6A circuit and chassis, the module mounts within the chassis by re-purposing the four speaker jack holes. Chassis rewiring is minimal. In addition to power and ground, only 2 wires insert the module into the existing Bassman signal path. Installation is straightforward and described in detail below.
Lush wet reverb is created with a real spring tank of your choice. Any tank with 8 or 10 ohm input impedance and medium output impedance can be used. A list of tank options is provided below. The reverb driver is a dedicated 2-3 watt power amp that drives the tank with the power needed to create deep vintage reverb. Unlike op amps, a real power amp drives the reverb tank harder, like vintage tube circuits. The recovery amp uses FET low noise circuits to keep hiss and hum all but inaudible. The FX loop is completely separate and independent of the reverb and also employs low noise circuits.
Lush wet reverb is created with a real spring tank of your choice. Any tank with 8 or 10 ohm input impedance and medium output impedance can be used. A list of tank options is provided below. The reverb driver is a dedicated 2-3 watt power amp that drives the tank with the power needed to create deep vintage reverb. Unlike op amps, a real power amp drives the reverb tank harder, like vintage tube circuits. The recovery amp uses FET low noise circuits to keep hiss and hum all but inaudible. The FX loop is completely separate and independent of the reverb and also employs low noise circuits.
The original amp signal (the Dry signal) is carefully handled and passed through the module so the original amp signal level, phase, and waveform are not impacted. Mixing the Dry signal with the reverb and FX signals is strictly additive. Unlike simple resistor mixing, there is no loss or change to the original Bassman signal. In fact the headroom of all the module circuits is greater than that of the Bassman circuits so module clipping or coloring of the Dry signal is impossible, even when driving the Bassman with gain pedals and fully cranked volume and tone settings.
The original amp signal (the Dry signal) is carefully handled and passed through the module so the original amp signal level, phase, and waveform are not impacted. Mixing the Dry signal with the reverb and FX signals is strictly additive. Unlike simple resistor mixing, there is no loss or change to the original Bassman signal. In fact the headroom of all the module circuits is greater than that of the Bassman circuits so module clipping or coloring of the Dry signal is impossible, even when driving the Bassman with gain pedals and fully cranked volume and tone settings.
In addition, the module includes dual bias controls on easily accessed pots that are sealed against dust and moisture. Setting output tube bias is simplified and more reliable. The ReverbFX3 includes all of these features in one module that fits perfectly into the 5F6A chassis and circuits.
In addition, the module includes dual bias controls on easily accessed pots that are sealed against dust and moisture. Setting output tube bias is simplified and more reliable. The ReverbFX3 includes all of these features in one module that fits perfectly into the 5F6A chassis and circuits.
The ReverbFX3 is constructed of high quality components and materials. There are no compromises in signal integrity or noise. The design is fully tested and validated under all playing conditions.
The ReverbFX3 is constructed of high quality components and materials. There are no compromises in signal integrity or noise. The design is fully tested and validated under all playing conditions.
How do I get it?
How do I get it?
The ReverbFX3 module is available assembled or as a kit. Amp-Aid is pleased to announce it has a distribution agreement with Kendrick Amplifiers. Contact Gerald Weber at 512 932 3130 or gerald20@earthlink.net to place an order.
The ReverbFX3 module is available assembled or as a kit. Amp-Aid is pleased to announce it has a distribution agreement with Kendrick Amplifiers. Contact Gerald Weber at 512 932 3130 or gerald20@earthlink.net to place an order.
If you're not comfortable building circuits, consider asking a qualified amp technician to do it for you.
If you're not comfortable building circuits, consider asking a qualified amp technician to do it for you.
How do I build and install the ReverbFX3 module?
How do I build and install the ReverbFX3 module?
Instructions for assembly and installation are below.
Instructions for assembly and installation are below.
I'm an amp technician, and I want to offer the ReverbFX3 installation to my clients.
I'm an amp technician, and I want to offer the ReverbFX3 installation to my clients.
Amp-Aid encourages amp technicians to offer ReverbFX3 installations to their clients. Skilled amp techs are in the best position to deliver a quality build and installation. Contact Gerald Weber at 512 932 3130 or gerald20@earthlink.net for more information or to place an order.
Amp-Aid encourages amp technicians to offer ReverbFX3 installations to their clients. Skilled amp techs are in the best position to deliver a quality build and installation. Contact Gerald Weber at 512 932 3130 or gerald20@earthlink.net for more information or to place an order.
Can the ReverbFX3 module be added to other amps?
Can the ReverbFX3 module be added to other amps?
The ReverbFX3 kit is designed for the 5F6A and its clones. However, other amps can use this module with appropriate component value changes. Whether you're planning a custom build, or considering an addition to an existing amp. The ReverbFX3 module will simplify your project and produce excellent results. The module can be adapted to work with almost any tube amplifier. Contact Gerald Weber at 512 932 3130 or gerald20@earthlink.net to discuss your project needs.
The ReverbFX3 kit is designed for the 5F6A and its clones. However, other amps can use this module with appropriate component value changes. Whether you're planning a custom build, or considering an addition to an existing amp. The ReverbFX3 module will simplify your project and produce excellent results. The module can be adapted to work with almost any tube amplifier. Contact Gerald Weber at 512 932 3130 or gerald20@earthlink.net to discuss your project needs.
Reverb tank options
Reverb tank options
Accutronics and MOD: 1ABxxxx, 4ABxxxx, 8ABxxxx, 9ABxxxxx
Accutronics and MOD: 1ABxxxx, 4ABxxxx, 8ABxxxx, 9ABxxxxx
Belton: BxxABxxxx
Belton: BxxABxxxx
(where "x" indicates that any option in the model number digit can be selected)
(where "x" indicates that any option in the model number digit can be selected)
ReverbFX3 build and installation instructions
ReverbFX3 build and installation instructions
Amp-Aid suggests careful reading of the information below prior to ordering or installing the ReverbFX3 module. The ReverbFX3 is designed for a standard 5F6A chassis and circuit. There are many variations of 5F6A amplifiers, so users should make sure all the installation steps are feasible in your particular amplifier.
Amp-Aid suggests careful reading of the information below prior to ordering or installing the ReverbFX3 module. The ReverbFX3 is designed for a standard 5F6A chassis and circuit. There are many variations of 5F6A amplifiers, so users should make sure all the installation steps are feasible in your particular amplifier.
The ReverbFX3 kit contains the following:
The ReverbFX3 kit contains the following:
PCB1 the module PC board
PCB1 the module PC board
All PCB parts
All PCB parts
Pointer knob
Pointer knob
24v power supply with two-sided foam adhesive
24v power supply with two-sided foam adhesive
Reverb tank and cables are not included - select these based on user preference and amp cabinet space.
Reverb tank and cables are not included - select these based on user preference and amp cabinet space.
ReverbFX3 Module Assembly
ReverbFX3 Module Assembly
Printed circuit assembly is straight forward by following the component layouts shown below. Both diagrams shows the component placements and outlines. The color image also shows the top-side board traces for reference. Resistors and film (rectangular) capacitors can be installed in any orientation. However, C4, C9, C15, C16, and C17 are electrolytic capacitors and must be installed in the indicated polarity/orientation. All semiconductors (diodes and transistors) must be installed in the indicated polarity/orientation. Note the alignment of the metal tabs on Q5 and Q6.
Printed circuit assembly is straight forward by following the component layouts shown below. Both diagrams shows the component placements and outlines. The color image also shows the top-side board traces for reference. Resistors and film (rectangular) capacitors can be installed in any orientation. However, C4, C9, C15, C16, and C17 are electrolytic capacitors and must be installed in the indicated polarity/orientation. All semiconductors (diodes and transistors) must be installed in the indicated polarity/orientation. Note the alignment of the metal tabs on Q5 and Q6.
NOTE: JP1 and JP2 are wire jumpers used to configure the board for use in varied amp circuits. For the 5F6A circuit, a clipped component lead should be soldered as a wire jumper for JP1. JP2 should be left open. Contact Gerald Weber for information about configuring these jumpers for other amplifier circuits.
NOTE: JP1 and JP2 are wire jumpers used to configure the board for use in varied amp circuits. For the 5F6A circuit, a clipped component lead should be soldered as a wire jumper for JP1. JP2 should be left open. Contact Gerald Weber for information about configuring these jumpers for other amplifier circuits.
If the effects loop (FXin and FXout) is not needed, it is advisable to short the FXin pad to the adjacent ground pads (FXG) using a short wire to prevent stray noise pickup.
If the effects loop (FXin and FXout) is not needed, it is advisable to short the FXin pad to the adjacent ground pads (FXG) using a short wire to prevent stray noise pickup.
Stop right here and seek professional assistance if you're not perfectly clear on how to build the circuit board.
Stop right here and seek professional assistance if you're not perfectly clear on how to build the circuit board.
When all the components are installed and soldered, check the board for orientation or placement errors and check the solder joints for suspect (cold) joints and errant solder bridges. High voltages are applied to the board during operation, so take your time and get it right. This is a case where it takes 10x as long to fix a problem than it takes to avoid one in the first place.
When all the components are installed and soldered, check the board for orientation or placement errors and check the solder joints for suspect (cold) joints and errant solder bridges. High voltages are applied to the board during operation, so take your time and get it right. This is a case where it takes 10x as long to fix a problem than it takes to avoid one in the first place.
The completed module looks generally like the image below. The appearance of the board below is slightly different from the current version due to the fact this image shows an early prototype PC board version. Use the layout diagrams above for component placement reference.
The completed module looks generally like the image below. The appearance of the board below is slightly different from the current version due to the fact this image shows an early prototype PC board version. Use the layout diagrams above for component placement reference.
Chassis Installation
Chassis Installation
Once the PCB is assembled, chassis installation can begin. The exact chassis appearance varies from case to case, but most 5F6A chassis should be similar. The prototype board images shown in the following instructions have a slightly different component layout, however, the board installation and connections between the board and the 5F6A amplifier are exactly the same for all board versions. Make sure you are completely comfortable with the outlined sequence of steps before you begin.
Once the PCB is assembled, chassis installation can begin. The exact chassis appearance varies from case to case, but most 5F6A chassis should be similar. The prototype board images shown in the following instructions have a slightly different component layout, however, the board installation and connections between the board and the 5F6A amplifier are exactly the same for all board versions. Make sure you are completely comfortable with the outlined sequence of steps before you begin.
Get a tech to help or do the install for you if you have any doubts or questions about any of this. It's not worth electrocution - whatever it is - it's not worth it.
Get a tech to help or do the install for you if you have any doubts or questions about any of this. It's not worth electrocution - whatever it is - it's not worth it.
1 - There are high voltage hazards in the amp so make sure you unplug it and discharge all capacitors before proceeding. Get professional tech help unless you know what you're doing and you understand the risks involved. The two layout figures below are derived from the Mojotone Tweed Bassman kit. They reflect the standard 5F6A layout, although originals and other clone amps will vary slightly. The gist of the instructions should be clear. If you have any questions or something is unclear to you, get help from a technician or contact Amp-Aid.
1 - There are high voltage hazards in the amp so make sure you unplug it and discharge all capacitors before proceeding. Get professional tech help unless you know what you're doing and you understand the risks involved. The two layout figures below are derived from the Mojotone Tweed Bassman kit. They reflect the standard 5F6A layout, although originals and other clone amps will vary slightly. The gist of the instructions should be clear. If you have any questions or something is unclear to you, get help from a technician or contact Amp-Aid.
2 - Remove the back cover to reveal the chassis internals. Compare your internals with those in the layout figures below. Make sure you can find the indicated circuit points in your amp.
2 - Remove the back cover to reveal the chassis internals. Compare your internals with those in the layout figures below. Make sure you can find the indicated circuit points in your amp.
3 - The Bassman has four speaker jacks connected to the output transformer secondary. Disconnect all the jacks and remove them. The holes marked J1 and P1 in the layout drawing below are used by the ReverbFX3 module. The hole marked "1" must be converted to a single 1/4 inch phone jack that feeds all speakers. A 1/4 inch jack requires an enlarged hole, so use a reamer to slightly enlarge that "1" hole for the jack. Insert and tighten the speaker jack in hole "1" and wire the OT secondary to it. The second layout figure shows the output transformer secondary connected only to Jack 1.
3 - The Bassman has four speaker jacks connected to the output transformer secondary. Disconnect all the jacks and remove them. The holes marked J1 and P1 in the layout drawing below are used by the ReverbFX3 module. The hole marked "1" must be converted to a single 1/4 inch phone jack that feeds all speakers. A 1/4 inch jack requires an enlarged hole, so use a reamer to slightly enlarge that "1" hole for the jack. Insert and tighten the speaker jack in hole "1" and wire the OT secondary to it. The second layout figure shows the output transformer secondary connected only to Jack 1.
Optional: If a pedal is desired to turn reverb on/off, a 1/4 phone jack should also be installed in the hole marked "2". Enlarge that hole until the jack fits. Insert and tighten that jack.
Optional: If a pedal is desired to turn reverb on/off, a 1/4 phone jack should also be installed in the hole marked "2". Enlarge that hole until the jack fits. Insert and tighten that jack.
4 - The "J1" and "P1" holes should still be empty. The "J1" hole needs to be enlarged for the stereo 1/4 inch jack (J1) on the module. This jack serves to both drive the pan and recover the pan signal. Carefully use a reamer to slowly enlarge the hole. Periodically check if J1 fits the opening and stop once it does. The "P1" hole should already be of sufficient size for the reverb control. The ReverbFX3 module should now fit in place. There may be a few wires that need to be moved aside, but the 5F6A chassis should not have anything in the area of the module that cannot be moved aside.
4 - The "J1" and "P1" holes should still be empty. The "J1" hole needs to be enlarged for the stereo 1/4 inch jack (J1) on the module. This jack serves to both drive the pan and recover the pan signal. Carefully use a reamer to slowly enlarge the hole. Periodically check if J1 fits the opening and stop once it does. The "P1" hole should already be of sufficient size for the reverb control. The ReverbFX3 module should now fit in place. There may be a few wires that need to be moved aside, but the 5F6A chassis should not have anything in the area of the module that cannot be moved aside.
Below is a picture of a Weber clone 5F6A before installing the module. Note the 1/4 inch speaker jack in hole "1" with the transformer secondary connected. Hole "2" has a 1/4 jack for a pedal. The "J1" and "P1" holes are empty and the "J1" hole has been slightly enlarged. Note the Accutronics 8AB2A1B reverb tank visible mounted on the bottom of the cab.
Below is a picture of a Weber clone 5F6A before installing the module. Note the 1/4 inch speaker jack in hole "1" with the transformer secondary connected. Hole "2" has a 1/4 jack for a pedal. The "J1" and "P1" holes are empty and the "J1" hole has been slightly enlarged. Note the Accutronics 8AB2A1B reverb tank visible mounted on the bottom of the cab.
The picture below shows the ReverbFX3 module in position. J1 and P1 stick out of the bottom of the chassis. Make sure the module PCB is clear of all contact with chassis or tube sockets or the other jacks. No part of the PCB should touch metal surfaces or connections.
The picture below shows the ReverbFX3 module in position. J1 and P1 stick out of the bottom of the chassis. Make sure the module PCB is clear of all contact with chassis or tube sockets or the other jacks. No part of the PCB should touch metal surfaces or connections.
5 - A small 24v power supply (included) is mounted on the side of the chassis near the power switches. See the photo below. The power supply is completely insulated, and attachment is by two-sided foam adhesive strip (included). Clearance above the power supply is needed for the bolt that holds the chassis to the cabinet, so ensure the power supply is flush with the chassis back opening and pressed gently down against the chassis bottom.
5 - A small 24v power supply (included) is mounted on the side of the chassis near the power switches. See the photo below. The power supply is completely insulated, and attachment is by two-sided foam adhesive strip (included). Clearance above the power supply is needed for the bolt that holds the chassis to the cabinet, so ensure the power supply is flush with the chassis back opening and pressed gently down against the chassis bottom.
Make sure the brown and blue wires are up towards the power switches and the red and back wires are down. The brown wire connects to 110-240 VAC. Connect it to the switched side of the AC switch. The blue wire is AC neutral and can be connected to the fuse or wire nut that is often used as AC neutral in many chassis. AC wiring varies from amp to amp, so make sure you identify appropriate connection points.
Make sure the brown and blue wires are up towards the power switches and the red and back wires are down. The brown wire connects to 110-240 VAC. Connect it to the switched side of the AC switch. The blue wire is AC neutral and can be connected to the fuse or wire nut that is often used as AC neutral in many chassis. AC wiring varies from amp to amp, so make sure you identify appropriate connection points.
The photo below shows the power supply in its correct position and orientation. The image also shows the Amp-Aid BMTrem2 module. Both fit into the same area without conflict. The layout figure below also shows the colored wire connections to the power supply.
The photo below shows the power supply in its correct position and orientation. The image also shows the Amp-Aid BMTrem2 module. Both fit into the same area without conflict. The layout figure below also shows the colored wire connections to the power supply.
6 - Remove the module from the chassis and prepare the Bassman circuits for installation. The layout figure below shows the initial speaker wiring and marks the wires that have already been removed or changed. In addition, there are 3 resistors to remove and one wire to remove from the standard Bassman circuit. Those are shown in red. Remove the 15k resistor in the bias circuit. Remove the two 220k grid leak resistors. Remove the wire from the treble pot wiper to the circuit board. Don't worry, the module will replace these components and connections with its own circuits.
6 - Remove the module from the chassis and prepare the Bassman circuits for installation. The layout figure below shows the initial speaker wiring and marks the wires that have already been removed or changed. In addition, there are 3 resistors to remove and one wire to remove from the standard Bassman circuit. Those are shown in red. Remove the 15k resistor in the bias circuit. Remove the two 220k grid leak resistors. Remove the wire from the treble pot wiper to the circuit board. Don't worry, the module will replace these components and connections with its own circuits.
7 - Now prepare the wire harness that connects the module to the Bassman circuits. To simplify the installation, measure wires first based on the eventual module position, and connect one end of each wire to the indicated Bassman chassis points. After all the wires are attached in the chassis, then install the ReverbFX3 module and solder all the wires to the module.
7 - Now prepare the wire harness that connects the module to the Bassman circuits. To simplify the installation, measure wires first based on the eventual module position, and connect one end of each wire to the indicated Bassman chassis points. After all the wires are attached in the chassis, then install the ReverbFX3 module and solder all the wires to the module.
The layout figure below has colored diamonds that identify connection points for the ReverbFX3 module. Each point is labeled with its module connection name. There are four connections to the right side of the module. B+ and Gnd are connections to the Bassman power supply at the points marked in layout figure 2. The In and Out connections replace the wire that was removed from the treble pot.
The layout figure below has colored diamonds that identify connection points for the ReverbFX3 module. Each point is labeled with its module connection name. There are four connections to the right side of the module. B+ and Gnd are connections to the Bassman power supply at the points marked in layout figure 2. The In and Out connections replace the wire that was removed from the treble pot.
The left side of the module has two connections (24 and Gnd) to the power supply installed in step 5. The red power supply wire connects to 24, and the black wire connects to Gnd, as shown. Since the red/black power supply wires are too short, they need to be extended with some 22 or 24 gauge hook up wire (not supplied). Solder the wire extensions and use insulating tape or heat shrink tubing to insulate the connections.
The left side of the module has two connections (24 and Gnd) to the power supply installed in step 5. The red power supply wire connects to 24, and the black wire connects to Gnd, as shown. Since the red/black power supply wires are too short, they need to be extended with some 22 or 24 gauge hook up wire (not supplied). Solder the wire extensions and use insulating tape or heat shrink tubing to insulate the connections.
Remember to measured and solder all wire harness chassis connections, but do not solder any wires to the module until all wires are prepared. Avoid excess wire length, although a bit of slack makes installation of the module easier. Reasonable lengths and direct wire paths ensure best results.
Remember to measured and solder all wire harness chassis connections, but do not solder any wires to the module until all wires are prepared. Avoid excess wire length, although a bit of slack makes installation of the module easier. Reasonable lengths and direct wire paths ensure best results.
The left module side also has connections to the Bassman bias circuits. The BiPS and BiRet connections are made to the points previously connected by the 15k resistor. Add wires that connect Bi1 and Bi2 to the points previously connected to the 220k grid leak resistors.
The left module side also has connections to the Bassman bias circuits. The BiPS and BiRet connections are made to the points previously connected by the 15k resistor. Add wires that connect Bi1 and Bi2 to the points previously connected to the 220k grid leak resistors.
The layout figure below shows all the wire harness connections and changes to the Bassman circuit.
The layout figure below shows all the wire harness connections and changes to the Bassman circuit.
As a sanity check, here is a classic Bassman schematic with the harness points and circuit changes marked. Note that the components and connections that were removed are marked with "x" and the speakers are all driven by one connector.
As a sanity check, here is a classic Bassman schematic with the harness points and circuit changes marked. Note that the components and connections that were removed are marked with "x" and the speakers are all driven by one connector.
Two options should be considered at this point. Neither in shown in the above wiring figures since they are not strictly needed and implementations may vary.
Two options should be considered at this point. Neither in shown in the above wiring figures since they are not strictly needed and implementations may vary.
Option1: If the effects loop is implemented, connectors for FXin and FXout must be available in the chassis and shielded wires run to the ReverbFX3 connections. Note that there are two ground pads (FXG) provided for shield ground connections on the module. Ideally, the FXin/out chassis connectors are isolated from chassis ground so the shielded wire connections provide the only connector ground. However good results may also be obtained with grounded chassis connectors.
Option1: If the effects loop is implemented, connectors for FXin and FXout must be available in the chassis and shielded wires run to the ReverbFX3 connections. Note that there are two ground pads (FXG) provided for shield ground connections on the module. Ideally, the FXin/out chassis connectors are isolated from chassis ground so the shielded wire connections provide the only connector ground. However good results may also be obtained with grounded chassis connectors.
Option2: If a reverb on/off pedal is implemented, the connector should be wired to the "Ped" pad on the module. If the speaker hole "2" has a jack for this purpose, add a short wire to the jack to reach the "Ped" pad. A chassis ground will serve for the pedal connector, so only a signal connection is needed from the "tip" connection of the jack to the module "Ped" pad. When "Ped" is floating, reverb is enabled. When "Ped" is grounded, the reverb signal is disabled. Note that Ped has no impact on the FXin/FXout signals. The external effects unit must provide a pedal to switch that effect on/off.
Option2: If a reverb on/off pedal is implemented, the connector should be wired to the "Ped" pad on the module. If the speaker hole "2" has a jack for this purpose, add a short wire to the jack to reach the "Ped" pad. A chassis ground will serve for the pedal connector, so only a signal connection is needed from the "tip" connection of the jack to the module "Ped" pad. When "Ped" is floating, reverb is enabled. When "Ped" is grounded, the reverb signal is disabled. Note that Ped has no impact on the FXin/FXout signals. The external effects unit must provide a pedal to switch that effect on/off.
8 - Once all the harness wires are attached to their circuit points, the ReverbFX3 module is permanently mounted in the chassis. Tighten the J1 and P1 bushings to hold the module in place. Tighten both nuts carefully to avoid stripping. The module is light weight and the two bushings offer ample support, but if additional support is desired, one of more of the holes around the module perimeter can attach to brackets or standoffs (user provided).
8 - Once all the harness wires are attached to their circuit points, the ReverbFX3 module is permanently mounted in the chassis. Tighten the J1 and P1 bushings to hold the module in place. Tighten both nuts carefully to avoid stripping. The module is light weight and the two bushings offer ample support, but if additional support is desired, one of more of the holes around the module perimeter can attach to brackets or standoffs (user provided).
9 - Now attach all the harness wires to their corresponding pads on the ReverbFX3 module. Wires are inserted from the rear and soldered on the front side of the module. Inspect all the wires and connections to make sure nothing is broken or misplaced and there is no contact between the module and surrounding metal. Fasten the knob to the reverb control. Below is an image of the module in place with harness connections.
9 - Now attach all the harness wires to their corresponding pads on the ReverbFX3 module. Wires are inserted from the rear and soldered on the front side of the module. Inspect all the wires and connections to make sure nothing is broken or misplaced and there is no contact between the module and surrounding metal. Fasten the knob to the reverb control. Below is an image of the module in place with harness connections.
10 - Before turning the amp on, turn the reverb control CCW to the minimum setting and center P2 and P3, the two bias controls (set the adjustment slots to vertical). Turn on the amp and adjust P2 and P3 to bias the output tubes to obtain your normal tube currents. Turning the pots CW should increase tube current. Usual 6L6 tube idle currents are between 35-40ma per tube. However, there are many variations of tubes, output transformers, power supplies, etc found in Bassman and clones, so what's "normal" for any specific amp will vary.
10 - Before turning the amp on, turn the reverb control CCW to the minimum setting and center P2 and P3, the two bias controls (set the adjustment slots to vertical). Turn on the amp and adjust P2 and P3 to bias the output tubes to obtain your normal tube currents. Turning the pots CW should increase tube current. Usual 6L6 tube idle currents are between 35-40ma per tube. However, there are many variations of tubes, output transformers, power supplies, etc found in Bassman and clones, so what's "normal" for any specific amp will vary.
Once bias is set, play the amp with the reverb control still at minimum to verify its normal operation. At the minimum reverb setting, only the Dry signal passes through the module so the amp should play with its original tone and behavior. Once normal amp operation is verified, the next step is to connect the reverb tank.
Once bias is set, play the amp with the reverb control still at minimum to verify its normal operation. At the minimum reverb setting, only the Dry signal passes through the module so the amp should play with its original tone and behavior. Once normal amp operation is verified, the next step is to connect the reverb tank.
11 - Prepare the connectors and cables for the reverb tank. Tank choice and installation details will depend on the amp cabinet and user preferences. Most tanks requires two RCA connectors, while the ReverbFX3 J1 connector requires a stereo 1/4 inch plug. Create the connectors and cables as shown in the figure below. Use shielded cable with both grounds connected at the phone plug sleeve. Mark the RCA plugs as Pan Drive (tank input) or Pan Recover (tank output) so they are clearly distinguished.
11 - Prepare the connectors and cables for the reverb tank. Tank choice and installation details will depend on the amp cabinet and user preferences. Most tanks requires two RCA connectors, while the ReverbFX3 J1 connector requires a stereo 1/4 inch plug. Create the connectors and cables as shown in the figure below. Use shielded cable with both grounds connected at the phone plug sleeve. Mark the RCA plugs as Pan Drive (tank input) or Pan Recover (tank output) so they are clearly distinguished.
Verify completed cable continuity with an ohmmeter before proceeding. Make sure the phone plug TIP connects to Pan Drive, and the phone plug RING connects to Pan Recover.
Verify completed cable continuity with an ohmmeter before proceeding. Make sure the phone plug TIP connects to Pan Drive, and the phone plug RING connects to Pan Recover.
12 - Replace the back cover of the amp. Plug the RCA connectors into the pan. Pan Drive is the tank "input" and Pan Recover is the tank "output". Insert the 1/4 inch plug into J1 on the ReverbFX3 module. Turn on the amplifier with reverb control still in CCW position, and verify amp operation.
12 - Replace the back cover of the amp. Plug the RCA connectors into the pan. Pan Drive is the tank "input" and Pan Recover is the tank "output". Insert the 1/4 inch plug into J1 on the ReverbFX3 module. Turn on the amplifier with reverb control still in CCW position, and verify amp operation.
When ready, turn the reverb control CW. At about 1/4 turn, you should begin to hear the reverb effect. Even at maximum reverb setting, the reverb should be clear and lush (and somewhat overwhelming). Mid control positions are most useful.
When ready, turn the reverb control CW. At about 1/4 turn, you should begin to hear the reverb effect. Even at maximum reverb setting, the reverb should be clear and lush (and somewhat overwhelming). Mid control positions are most useful.
If you implemented the reverb pedal, plug in an on/off pedal and test its operation. If you installed FXin/out jacks, test those with an external effects unit. While FX signal levels will vary greatly with amp input levels and control settings, nominal levels of 1-2 volts peak can be expected. Adjust the input and output levels of the external effects unit for desired results.
If you implemented the reverb pedal, plug in an on/off pedal and test its operation. If you installed FXin/out jacks, test those with an external effects unit. While FX signal levels will vary greatly with amp input levels and control settings, nominal levels of 1-2 volts peak can be expected. Adjust the input and output levels of the external effects unit for desired results.
That's it - enjoy the new sweet reverb tones coming from your Bassman. We hope you're as pleased with the outcome as we are proud to make it possible.
That's it - enjoy the new sweet reverb tones coming from your Bassman. We hope you're as pleased with the outcome as we are proud to make it possible.
We're happy to hear from techs and/or players. Send us your comments and reactions.
We're happy to hear from techs and/or players. Send us your comments and reactions.
DISCLAIMER: Amp-Aid is not liable for any damages or injuries in connection with this kit or with any amplifier. The customer must determine suitability of this product, and be responsible for its construction, installation, and use.
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