BANDMASTER AB763 SCHEMATIC FULL
BANDMASTER AB763 SCHEMATIC MODS

Hi input jack at left and ends at the speaker at upper right. Signal path above is shown by a thick red line. The amp's signal flow in the schematic below is shown by the thickįrom the Vibrato input jack on the left to the speaker at upper right. Most Fender aficionados consider the AB763Ĭircuit to be the Fender high water mark. Standard so high that all of the following circuit changes failed to Modern perspective the AB763 amp circuit is a benchmark which set the Fender Offers up plenty of power tube distortion.

BANDMASTER AB763 SCHEMATIC FULL

Its long tail pair (LTP) phase inverter can drive the 6V6 power tubes to full distortion at high volume settings so it Sounds a little spongy and more 'tubey' than the other AB763 amps.įixed bias power tubes sound clean, punchy and loud compared to earlier FenderĬathode biased amps. Voltage sag caused by the undersized power transformer and the Deluxe Reverb Which adds to touch sensitivity and sustain. The AB763 Deluxe Reverb's slightly undersized output transformer creates output volume compression at high volume levels

The extra gain stage (triode V4B) more than makes up for the loss and the Vibrato Channel ends up being the higher gain of Make up for losses incurred by the reverb and tremolo circuits. Reverb and tremolo (vibrato) effects into the signal chain and has another The Vibrato Channel has the Normal Channel's topology but adds the The Normal Channel, so much so that many AB763 players never use the NormalĬhannel. The Vibrato Channel in the AB763 is very different from Tone Stack Works for more info on the tone stacks. With the Treble and Bass tone controls set to maximum the tone curve clearly Graphĭeluxe Reverb Mid Scoop With Treble and Bass Set to Maximum The Mid control is set to 6.8k to simulate a fixed 6.8k Middle Resistor. This is what's meant when people say the TMB tone stack 'loads down' the signal. Relatively flat but the guitar signal is losing about 25dB to the tone stack. With the Treble and Bass tone controls set to minimum the tone curve is (Treble, Mid, Bass) tone stack sets this mid frequency scoop. The AB763 blackface tone is known for its 'mid scoop.' You can firm up the Deluxe Reverb with a larger firstįilter capacitor or even an upgraded power transformer but you will lose some of Have higher output power supplies that do not suffer from the Deluxe Reverb's The other AB763 amps like the Twin Reverb The AB763'sĬlean, clear tone comes from the use of lots of negative feedback.ĭeluxe Reverb is known for its under rated power supply which gives the ampĪ lot of feel and touch response but leads to a loose low end and even 'farting This trait also makes the AB763 circuit very pedalįriendly-it can play loud and clean to let the pedals do their thing. Ubiquitous voice are its mid scoop tone and loud and clear, but not too sterile character, especially when compared

Some of the elements that give the AB763 Deluxe Reverb such a Output Transformer are attached to the bottom of the chassis. The AB763 Deluxe Reverb ChassisĬontrols in front, Circuit Board inside, tubes on bottom and out of view. Page dedicated to the magical 5F6-A tweed BassmanĪmp and the ever popular 5E3 Deluxe.

Tube theory and other introductory material here so check it out if you have Tubes work in the very simple Fender 5F1 Champ. I recommend you take a look at my How Tube Amps Work and How Vacuum Tubes Work webpages for a detailed The 'blackface' nickname comes from the control panel Of how the amp circuit works, what each component does, and how changing those

I will try my best to give a not-too-technical explanation Vibroverb, Tremolux and no-reverb Deluxe. The '763' in the model name comes from the circuit change dateĭeluxe Reverb, Twin Reverb, Super Reverb, Bandmaster, Showman, Pro, Vibrolux, 'AB763' was Fender's internal model designation for the 1963Ĭircuit. Have comments or corrections? Email rob at: robinette at

BANDMASTER AB763 SCHEMATIC MODS

DRRI & 68 CDR Mods ] ] How the Fender AB763 Blackface Deluxe Reverb Amp Works The non-electronic tech's guide to understanding the classic AB763

Bandmaster ab763 schematic