Three-digit
serial numbers
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on a Bass-Master
might indicate that the amp is from 1965 or 1966, before the four-digit serial
numbers were used.
The circuit in [that amps] is built on a phenolic turret board instead of the
Fender style fibre board used [later.]
[...] it appears that Traynor/Yorkville used three digit serial numbers up until 1968. [An example is an] YBA-1A Bass Master Mark II [...] with the serial number M 601 [...] [whose] potentiometers date from 1968 [...] [and on which] 'Range Expander' is screened below the controls, not above.
(Eric Knudsen,
Rob Mercure,
Scott)
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Four-digit
serial numbers
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seem to follow this pattern
[I assume my Bass-Master, YBA-1 is from 1971, serial n. 5XXX]
1966 0XXX
1967 1XXX
1968 2XXX
1969 3XXX
1970 4XXX
1971 5XXX
(dhr)
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Seven-digit
serial numbers
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are coded as follows
s/n: 1020629
First digit: Last digit of year of production (1 ^= 1971, 3 ^= 1973)
Second and third digit: Month of production (01 ^= Jan., 11^=Nov.)
Last four digits: Numbered unit produced within that year?
(JRogersjr)
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Filter caps/Circuit breakers
codes
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dates coded as follows
Mallory capacitor code 235-7051Y:
235 is Mallory's EIA code, 51st [week] of 1970
Mel Rain Corp circuit breaker code 834-7305:
[834 is Mel Rain Corp's EIA code,] 5th week of 1973
Mel Rain Corp circuit breaker code 834-7328:
[834 is Mel Rain Corp's EIA code,] 28th week of 1973
(Eric Knudsen)
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Other dates
etc.
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Dates on schematics etc.
Often there are schematics inside an amp with sometimes hand-written
revision dates on them, or on other pieces of paper, e. g. quality control
etc.
(-)
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