File Size: Kb Number of Views: After downloading, the file may take a moment to open in the browser. Fender – Bassman 5f6a -Schematic Thumbnail. The Bassman 5F6-A preamp contains two voltage amplifiers, one for the bright inputs and one for the Fender Bassman 5F6-A schematic of first two stages. 5F6A Amp Kit Item Code: 5f6a_c_kt We provide a layout and a schematic (on the Technical Details tab), but we do not include step by step assembly.

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The input resistor on the Hi input jack sets the amp’s input schekatic and acts as the V1B grid leak resistor. For amps with k grid leaks use a k pot and for amps with k grid leaks use a k pot. This master volume controls the signal level feeding the power tubes so you can use it for lower volume distortion and to control the balance between preamp and power tube distortion. The Presence control R35 and C21 removes a variable amount of high frequency from the negative feedback signal.

Another option to consider is changing the Normal channel’s. The 6V6, 6L6 and KTxx tubes have internal jumpers that do this. Increasing the value of the two schmeatic filter caps can help reduce 60Hz hum. A voltage elevated Humdinger can eliminate more heater hum than any other type of heater real or 5f6z center tap. There’s a small chance the Ice Pick Cap can induce oscillation at high volume.

The diode stripe marks the cathode and negative end of the diode. When a positive voltage signal arrives at the schematlc grid the reduction of blocking negative electrons on the grid allows electrons to flow from its cathode, through the grid, to its plate.

The “Raw Control” is a pot that controls the amount of tone stack bypass.

This is a universal circuit that can be used on pretty much any amp with a bridge rectifier. The new resistor will function as the V2A preamp’s grid stopper and help control the heavy overdrive caused by the cascade mod. Heater current in amps: It’s mounted on the preamp side to clear the transformers. Remove your current 6.


Prowess Amplifiers – Fender – Schematics – Bassman 5f6a – Schematic

The following seven mods add versatility but are switchable so I can run the amp as a normal 5F6A. You tap high voltage AC from the rectifier AC input and create an adjustable bias circuit.

Notice how multiconductor Mini-Star-Quad shielded cable is used to keep AC noise out from the power transformer and power lines. Put two wire wraps around the turret. In the diagrams below the switch is connected to the V2A cathode pin 3 but this switch could also 5c6a used on V1A pin 3 or V1B pin 8 if you remove the jumper between V1’s cathode pins 3 and 8 to separate the two cathodes.

Some Marshall amps have one channel 5c6a hot with scheatic ohm cathode resistor and the other biased cool with a 2. Since channel jumpering is so common among Fender players this mod will let you leave your jumper cable at home and jumper the Bright and Normal channels with the pull of the Normal volume knob. Then ground the other end of the 27k resistor at any convenient ground. Carl’s Custom Guitar’s Speaker Soak attenuator installed at upper right to allow for less-than-ear-splitting practice.

List of Mods

Upgrade the two tiny 8uF bias circuit schemayic caps to 50uF to reduce 60Hz hum. If you do go with Weber I recommend you have Weber break their speakers in for you so they will sound great right out of the box. Increasing the V1A load resistor from k to k will increase the channel’s gain and make distortion in the V2A preamp more likely. If your power transformer svhematic not come with a 6.

Fender Bassman 5F6A Amplifier Project – By Edmund Henke on Behance

Two 1N diodes running from the tube plate pins to ground will do the trick. My circuit increases the value of the two filter caps to reduce hum and reverses the value of the pot and resistor to increase the bias range to work with more amps and tube types.


Connect resistors R44 and R45 power tube grid stopper resistors to the Master Volume pot. AC from the power transformer: The Fender 5F6A schematic shows v as the bias voltage for tubes which would yield a significantly cooler bias. Tone Stack Fender’s 3-knob tone stack architecture is perhaps the most copied electronic circuit in music electronics.

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The voltage drop of an LED is about 1. Turn on the Power Switch then wait around 15 seconds for the tube heaters to come up to temp and for the pop resistor to charge the filter caps enough to prevent a current inrush which is what causes the pop.

The bias pot wired as a variable resistor and 27k resistor replace the 56k resistor above. My circuit increases the value of the two filter caps to reduce hum and increases the value of the pot to increase the bias range to work with more amps and tube types. If your power transformer does have a 6.

We do not recommend anyone attempting to build any of our kits that are rated at 3 or higher in complexity unless you have the assistance of a qualified amp builder or electronics technician. It is the first triode to go into overdrive and its interaction with the upstream gain stage adds a unique overdrive effect that limits clipping of both the positive and negative signal lobes. I get my Zener diodes from Mouser.

This is a universal circuit that can be used on pretty much any amp. The cab is a 5E3 combo but it’s vented and sized so it can also be used as a sealed back extension cab you can’t seal the back and run the 5E3 due to heat buildup. Pre Phase Inverter Master Volume in the standby switch hole.