70s Fender Twin Reverb ID

[ca7922303]

Have a '73 according to numbers on transformers and back plate is s similar to another '73 I just had, but this backplate reads 135 watts which I believe to be '77-'81? Any info appreciated. Thanks.

[ca7922303]

Have a '73 according to numbers on transformers and back plate is s similar to another '73 I just had, but this backplate reads 135 watts which I believe to be '77-'81? Any info appreciated. Thanks.

1st two photos is the 135 watt backplate with transformers that read '73, second two is 135 watt backplate with transformers that read '78, third two photos are transformers that read '73 with backplate of 100 watts.

[glebert]

UL output transformer should have a couple extra leads on the primary side, right?

[ca7922303]

UL output transformer should have a couple extra leads on the primary side, right?

That preset voltage switch on the 2nd group of two photos is throwing me. The 1st and third group of photos have transformers that are marked '73, but one has a 100w backplate, the other a 135w backplate and they both have an ac outlet on back which is consistent with a '73 I believe, but a '73 is not supposed to have a 135w backplate unless someone put the wrong backplate on it?

[ca7922303]

That preset voltage switch on the 2nd group of two photos is throwing me. The 1st and third group of photos have transformers that are marked '73, but one has a 100w backplate, the other a 135w backplate and they both have an ac outlet on back which is consistent with a '73 I believe, but a '73 is not supposed to have a 135w backplate unless someone put the wrong backplate on it?

Also noticing that group 1 & 2 of photos has a hum balance, line/recording, and a output tubes matching pots that group 3 doesn't.

[Helmholtz]

That preset voltage switch on the 2nd group of two photos is throwing me.

Why that? They're just export models. All of my BF and SF Fender amps (naturally) have it.
Also check for MV with or without push-pull switch.

[g1]

The following is taken from this link: http://www.superiormusic.com/page195.htm

1970-1989 -Most amps do not have a date code stamped on the tube location chart. These codes are for amps with the serial number beginning with a letter:
B+5---digits - 1975-1976
A6+5-digits - 1976
A7+5-digits - 1977
A8+5-digits - 1978
A9+5-digits - 1979
F0+5--digits - 1980
F1+5--digits - 1981
F2+5-digits - 1982/83
F3+5-digits - 1983/84
F4+5-digits - 1984/85
F9+5-digits - 1979-1980

Twin Reverb AB763, AC568, AA769, AA270 (silverface)
A10500 to A11300 - 1967
A10500 to A16500 - 1968
A16500 to A21400 - 1969
A21400 to A25600 - 1970
0100 to 3400 - 1970
A25600 to A37000 - 1971
A37000 to A50500 - 1972
A50500 to A68000 - 1973
A68000 to A99999 - 1974
A81000 to A99999 - 1975
B01000 to B15000 - 1975
B15000 to B68000 - 1976

[glebert]

I would also say it is not unheard of to take two not working amps and combine them into one, so transformers and chassis (and backplate) might not match. I had a Vibroverb clone that was made with a 73 Super Reverb chassis, which looked pretty correct except that it had a 2 ohm load spec on the backplate.

[ca7922303]

The following is taken from this link: http://www.superiormusic.com/page195.htm

1970-1989 -Most amps do not have a date code stamped on the tube location chart. These codes are for amps with the serial number beginning with a letter:
B+5---digits - 1975-1976
A6+5-digits - 1976
A7+5-digits - 1977
A8+5-digits - 1978
A9+5-digits - 1979
F0+5--digits - 1980
F1+5--digits - 1981
F2+5-digits - 1982/83
F3+5-digits - 1983/84
F4+5-digits - 1984/85
F9+5-digits - 1979-1980

Twin Reverb AB763, AC568, AA769, AA270 (silverface)
A10500 to A11300 - 1967
A10500 to A16500 - 1968
A16500 to A21400 - 1969
A21400 to A25600 - 1970
0100 to 3400 - 1970
A25600 to A37000 - 1971
A37000 to A50500 - 1972
A50500 to A68000 - 1973
A68000 to A99999 - 1974
A81000 to A99999 - 1975
B01000 to B15000 - 1975
B15000 to B68000 - 1976

Appreciate that. So group 1 photos turn out to be a'77 serial number with '73 stamped transformers and group 2 of photos has '78 serial number with '78 stamped on transformers. Both of those have push/pull master volume. Don't recall the '73 master volume. Guessing not.