In any case, why the bods at Fender saw need to replicate the chassis in so many slightly-varied guises is baffling… but we’re glad they did. The original Jensen P10R speakers are a big part of this amp’s appeal – and its superb tone. Some had minor differences like values for negative-feedback resistors to fine-tune headroom or match the NFB loop to the output impedance for optimum speaker damping. The 3×10″ 5E7 Bandmaster, 2×10″ 5F4 Super, and 1×15″ 5E5-A Pro were all essentially the same amp, other than speaker complement, output transformer, and occasional minor tweak in components (similar was the 2×12″ 5E8-A “low-powered” Twin of ’55-’58). In ’55, it took up the 3×10/narrow-panel configuration that then evolved to the more-desirable iterations of 1959. The Bandmaster arrived mid ’53 in a short-lived 1×15″ incarnation of Fender’s wide-panel tweed cab. Controls: Volume for Microphone and Instrument channels shared Treble, Bass, and Presence.And if you’re prepared to altogether collapse in a gelatinous heap, consider that the VG reader who owns this one also owns its successor, the 5G7 “middle-volume” pinkish-brown-Tolex Bandmaster – possibly the rarest of all production Fenders. There’s just something about the 3×10″ 5E7 Bandmaster that drives vintage-Fender nuts gaga. These are not the small magnet G12-20s, but are actually 25W Greenbacks with a different cone, sounding different than a typical 25W Greenback from a 1960s 4×12″ cab.If ever there was an amp to make a fan of tweeds go wobbly in the knees, this is it. These G12-20 speakers were ‘M’ ceramic magnet speakers with an H1777 cone. The speakers were two 12″ Celestion G12-20 speakers. Very few of the 1972 2×12″ (horizontal) extension cabinets (for the JTM45 1962 amp) were built and these cabinets are very rare. Late 1965 or early 1966 the ceramic speakers were replacing the AlNiCos. These 12″ AlNiCo speakers were essentially the same speaker as the Celestion VOX Blue speakers. They were angled front cabinets and were fitted with four 12″ Celestion G12-15 speakers, instead of the four 10″ Jensen speakers in an open cabinet like Fender did. In 1964 these cabinets were given the model number 1960. These first speaker cabinets didn’t have a model number at first. This amp was in production from 1965 to 1966. Schematic with 4x ECC83, 2x KT66 & GZ34 (Marshall). The original JTM45 was renamed to this model 1987. Schematic with 4x ECC83 & 2x KT66 (Marshall). These PA amps had JTM 45 and MK III printed on the front panels. Note that the typical 100pF bright cap wasn’t fitted on the earliest models. This was the amp Eric Clapton used on the legendary John Mayall’s Bluesbreakers “Beano” album early in 1966. This amp used the 1986 bass tremolo chassis in a 2×12″ combo cabinet. JTM45 1962 Bass & Lead, 45W 2×12″ combo (Blues Breaker) This amp used the 1987 tremolo chassis in a 4×10″ combo cabinet. Schematic of the Bassman Tweed 5F6-A Amp (Fender). Later (probably in 1963) aluminium panels were used having JTM 45 and MK II printed on them (implying the first serie of amps were MK I). The first JTM45 amps had no model number printed on them. There was also a power switch and a standby switch with a power indicator. Next came the low, mid, high & presence controls. These amps had 2 channels with each a volume control and two inputs (making a total of four inputs). Sometime (late) in 1966 these mix resistors were raised in value to 470kΩ. The mix resistors (which mix together both channels after the first triode sections) were originally 270kΩ on the early models. The Fender Bassman used a 12AY7 as the input tube but the JTM45 was fitted with a ECC83/12AX7 which has a higher gain. It is said that the first prototype and early production amps were fitted with two 5881 beam power tetrodes, three ECC83/12AX7 tubes and a GZ34 rectifier tube, but soon KT66 tubes were used instead of the 5881 tubes. The circuit was a 1959 Fender Tweed Bassman (circuit 5F6-A) clone. It didn’t actually have a model name or number at first, but later it was called the JTM45. These were the very first Marshall combos. In these early years the amps, their circuits and especially the cosmetics varied a lot.Įarly 1965 saw the introduction of models 19. The very first (prototype) Marshall amps were built in 1962 in Jims kitchen.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |