5F6-A Tweed Bassman Electronics Component Pack

Before purchasing read this

Build your own Fender 5F6-A Tweed Bassman, one of the most famous guitar amps ever made and the circuit Marshall based the JTM45 on. Two channels, a full Treble, Bass, Middle and Presence tone stack, a long-tail phase inverter and a pair of 5881 power valves give it big, punchy clean tones and a thick, singing overdrive when you turn it up.

This pack contains the electronic and hardware components needed to assemble a complete 5F6-A chassis, from the transformers, choke and valves down to the wire, screws and solder lugs. The full list, with quantities, is below.

There are a range of 5F6-A schematics and layouts on the internet. This pack is based on Rob Robinette's 5F6-A layout, which we feel is one of the clearest and best documented. Rob covers the circuit and dozens of popular changes in his 5F6-A Bassman modifications guide. Please check every part against the schematic and layout you build from.

Kit Features & Highlights

• Two Channels, Four Inputs: Normal and Bright channels, each with its own volume and Hi and Lo inputs. Jump the channels for the classic thick tweed sound.
• Full Tone Stack: Treble, Bass and Middle controls plus a Presence control in the negative feedback loop, the layout that inspired a generation of Marshall and Fender amps.
• Authentic Valve Tone: A 12AY7 and two 12AX7s in the preamp and phase inverter, a matched pair of Tung-Sol 5881 power valves and a GZ34 / 5AR4 valve rectifier.
• Genuine Hammond Iron: 290D2EX 240V power transformer, 1750K output transformer with the original 2 Ω secondary, and a 194B choke.
• Ready to Build On: Includes a 5F6A narrow-panel chassis, a 5F6A turret board with its separate filter cap board, Fender-style ceramic sockets, CTS pots, vintage cloth pushback wire, and every resistor and capacitor on the list below.

What's Included in the Box

Every item and quantity in the pack. Where an item is a pack (fuses, screws, solder lugs, stand-offs), the quantity is the number of packs.

About the layout: Rob Robinette's layout adds a standby switch with a small anti-pop capacitor to the original 1950s circuit, and this pack includes both. The original schematic shows a 5kΩ Presence pot, but most production amps used 25kΩ, which is what we supply. The bias is fixed, as on the original; if you want to add a bias adjustment pot, Rob's guide shows how.

Speaker load: the 1750K output transformer has a 2 Ω secondary, like the original. That suits the classic four 8 Ω 10" speakers wired in parallel. Always match your speaker load to the output transformer.

Knobs are not included, so you can choose the style that suits your build. Browse our amplifier knobs range to find a set for your 6 controls.

Product Specifications

• Output Power: ~40–50 Watts RMS
• Preamp Valves: 1 x 12AY7 / 6072A (V1) and 1 x 12AX7 / ECC83 (V2)
• Phase Inverter: 1 x 12AX7 / ECC83 (V3), long-tail pair
• Power Valves: 2 x 5881 (6L6GC also suits), fixed bias
• Rectifier Valve: 1 x GZ34 / 5AR4
• Controls: Normal Volume, Bright Volume, Treble, Bass, Middle, Presence; 2 inputs per channel
• Impedance Output: 2 Ohm (four 8 Ω speakers in parallel)

Finish Your Tweed Bassman

The classic Bassman sound comes from four 10" speakers. We recommend four Jensen P10R 8 Ω speakers for vintage tone, or four Jensen P10Q 8 Ω speakers for more headroom. For the period-correct look, cover the cabinet in our gold tweed authentic woven fabric and choose from our grill cloth range; our free Tolex & Grill Cloth Estimator tells you how much to order. See our 5F6-A Tweed Bassman parts list for everything else, including tools.