Fender Bandmaster

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The Fender Bandmaster was a musical instrument amplifier made by Fender. It was introduced in 1953 and discontinued in 1974.[1] Some early models had both a microphone input and instrument inputs. Beginning in 1960, Bandmaster amps were equipped with a vibrato effect. In the 2000s, vintage Bandmaster amps remain in use by blues, Americana and rock and roll bands.

Timeline[edit]

Timeline gleaned from[1]

Year Inputs Output Form Speakers Controls Circuit/Model Price
1953 2 instr, 1 mic Combo (Wide Panel)
Tweed
(1) 15" + ext jack
Jensen P15N
Volume, Treble, Bass 5C7 $229.50
1954 2 instr, 1 mic Combo (Wide Panel)
Tweed
(1) 15" + ext jack Volume, Treble, Bass 5D7
1955 2 instr, 1 mic 26 watts Combo (Narrow Panel)
Tweed
(3) 10" + ext jack Volume, Treble, Bass, Presence 5E7
April 1960 2 channels, each with

high & low sensitivity
input jacks

40 watts Combo
(w/Modern Fender style)
brown Tolex
each channel: Treble, Bass, Volume

Vibrato channel also: Speed, Intensity
master Presence

6G7
End 1960 2 channels, each with

high & low sensitivity
input jacks

40 watts Combo
brown Tolex
each channel: Volume, Treble, Bass

Vibrato channel also: Speed, Intensity
master Presence

6G7-A
Feb 1961-

June 1963

2 channels, each with

high & low sensitivity
input jacks

40 Watts Piggyback ("head")
cream Tolex
(2) 12" + ext. jack

Oxford 12M6-10, Jensen C12N

each channel: Volume, Treble, Bass

Vibrato channel also: Speed, Intensity
master Presence

6G7-A
July 1963 2 channels, each with

high & low sensitivity
input jacks

40 watts Piggyback ("head")
black Tolex
None each channel: Volume, Treble, Bass

Vibrato channel also: Speed, Intensity
Presence removed, "Bright" added

AB763
1968 2 channels, each with

high & low sensitivity
input jacks

Piggyback ("head") None each channel: Volume, Treble, Bass

Vibrato channel also: Speed, Intensity
Bright

AA568
1969 2 channels, each with

high & low sensitivity
input jacks

Piggyback ("head") None each channel: Volume, Treble, Bass

Vibrato channel also: Speed, Intensity
Bright

AA1069
1974 Discontinued . . . . .

Cosmetics[edit]

Circuit notes[edit]

5C7[edit]

The first Bandmaster was in all respects almost identical to the Fender Pro, a dual-6L6 26-watt amp with a 1x15 speaker, with one difference: separate treble and bass controls, where the Pro like all other Fender amps to that time only had a single "Tone" knob. Like the other larger Fender amps, the Bandmaster used cathode-biased 6L6G output tubes, a 6SC7 paraphase inverter, and two more 6SC7s in the preamp with a 5U4 rectifier.

5D7[edit]

The D-series circuits represented Fender's shift from octal preamp tubes, e.g. the 6SC7, to nine-pin mini-tubes of the 12A(n)7 family, as well as the introduction of the floating-paraphase inverter.

5E7[edit]

Negative feedback and filter choke added, and the output section given fixed (grid) rather than cathode bias. Phase inverter changed to cathodyne (concertina) type.

6G7-A[edit]

The 6G(n)-A circuit was used in several Fender amplifiers, including the Bandmaster.[2] It produces 40 watts into 4 ohms. The circuit was used from 1961 until July 1963 when the "AB763" circuit was introduced. "Blonde" aficionados feel this circuit has superior tonal characteristics when overdriven, to the AB763 circuit. The 6G7-A circuit used the long-tail pair phase inverter introduced with the 1957 Bassman, and also included a vibrato that is heralded as Fender's best by many enthusiasts. Power tubes were now 5881s (6L6WGBs).[3]

AA/AB763[edit]

The AA763 (July 1963) and improved AB763 (March 1964) circuit is arguably considered the "best" circuit version produced for this amp by collectors and aficionados. The complex brownface "harmonic vibrato", however, was replaced by a simpler electro-optic oscillator. Power tubes were the even beefier 6L6GC. Amps retrofitted to this circuitry are described as having been "blackfaced," a reference to the black faceplate used on these amps during much of this era.

AA568[edit]

The AA568 version (introduced May, 1968) was met with popular dislike by Fender's customers. It is referred to at times as the "silverface" circuit, referring to the brushed aluminum control plate used from 1968 to 1974. The circuit change and the cosmetic change didn't happen at the same time; some 1967 and early 1968 Bandmasters still possessed the AB763 circuitry.

Unfortunately, the tube chart inside the amp head cannot be reliably used to differentiate the AB763 from the later circuits, as Fender continued using the older tube charts for a while after changing the circuit configuration.

AA1069[edit]

Some of the changes from the AA568 were reverted in October, 1969, yielding the AA1069 circuit, but many of the changes remained in place.

See also[edit]

References[edit]

  1. ^ a b Teagle, J. and Sprung, J.: Fender Amps: The First Fifty Years
  2. ^ 6G4-A (Super), 6G5-A (Pro), 6G7-A (Bandmaster), 6G12-A (Concert) and 6G13-A (Vibrasonic), together with an 85-watt four output-tube variant 6G8-A (Twin) and 6G14-A (Showman)
  3. ^ schema electrique pour un fender ban master 1961