Comments: The Showman 12, Showman 15, and Double Showman all used the same head with the only difference being the size and speakers of the the speaker cabinet. Oxblood grilled Double Showmans exist, but are very rare. The harmonic vibrato tremolo circuit left half a dual triode (7025 or 12AX7) unused.
Thanks for your input. The Showman I have demonstrates that your information is still not complete. I have a serial #378 so a pretty early Showman that was eventually converted in Fender to an “A” probably, and it’s marked as an “ex Dick Dale” (who knows the truth). Anyway, my output transformer is actually a 45268 at 4-ohms coupled with a 67233 power transformer, so as you can see the Showman also installed the 45268, not only the Twin, and I was told also that these transformers were common in the Concert too and other amps. Fender was always using the parts he already had in stock before starting using new ones. You are absolutely right though, there are many variations of the same amp and, having personally compared quite a few of them, they all sound different. Some definitely sound louder and more “middy”, more blackface; some others break up a bit earlier, have more character, more bass, but less presence.
David, Often enough, for each component in the Fender product line, it’s just what was happenstantially available in appropriate quantities for any given production order period. This is borne out in the choice of the 4-terminal treble pots used during the Brownface era as well as the size of the choke used in the late professional-series Tweed amps. So the answer as to why certain transformers, chokes or even a 350k potentiometer with a 70k tap was used is because it was available, it was applicable, and it was cheap! So, even though that Tweed-era choke was huge and has a 400mA rating. It was just an “off the shelf” unit (according to Patrick Selvedge at Mercury Magnetics) that fit the application at a price that satisfied the economics of Fender production at the time.
Between the Tweed Twin with front-facing controls and the Blonde Showman amplifiers, there were no fewer than six different output transformers used—some clearly offering different impedance ratings, and others, who knows. Transformers for the Twin were not used on the Showman, and vice versa. Both the front-control Twin and the debut Showman were introduced using 6L6GC tubes, with the “A” versions later switching back to 5881 tubes (industrial 6L6GB). The different transformers were as follows: the Twin used 45268 and 45548, both with 4Ω secondaries. While the 45268 was paired with tube rectifiers, both were also used with solid-state power supplies. This raises the question—why two different transformers, especially since they started with the 45268, switched to the 45548, and then returned to the 45268, all while the output stage and speaker load remained essentially unchanged? The Showman started with the 45550 transformer (a sister to the Twin’s 45548, likely with an 8Ω secondary). The “A” version then possibly used the 45945, 45946, and eventually the 125A4A. It has been reported that the 45946 was a 16Ω transformer and the 125A4A an 8Ω transformer, but the specs for the 45945 remain uncertain. There is a lot of misinformation online about these amplifiers, so anything unverified should be treated with caution. I have personally seen all of these transformers except the 45548 and 45550. Among them, all the others are physically quite large—nearly twice the size of the classic 125A29A and 125A30A transformers used in all the Blackface Showmans. There was even another set of transformers for the very rare Showmans built to use 7355 tubes, though those are of little interest here. So, does anyone have credible input as to why there were two transformers for the Twin that appear otherwise identical, and why there were four transformers for the Showman when only three possible output impedance levels would have been needed? The 45548 and 45550 transformers were the only ones in the group that specified 6L6GC tubes; the rest specified 5881 tubes—though this distinction is minimal, as the 6L6GC is simply a higher-rated 5881 with otherwise identical characteristics. All of these amplifiers were powered by the same 67233/123P7A power transformer, which ultimately determines how much power an amplifier can produce. Any input on the specifics of these Showman transformers, or why the Twin used two seemingly identical ones, would be appreciated!
I’ve seen some with tapped tone controls. Which variation were these?
The 6G14 and 6G14A circuits are entirely different preamp topologies. The 6G14 Showman and 6G8 Twin employed the “James” preamp circuit. The latter circuit with the (A) signifier was the original precursor to the famous AB763 Blackface circuit.
7 comments
Thanks for your input. The Showman I have demonstrates that your information is still not complete. I have a serial #378 so a pretty early Showman that was eventually converted in Fender to an “A” probably, and it’s marked as an “ex Dick Dale” (who knows the truth). Anyway, my output transformer is actually a 45268 at 4-ohms coupled with a 67233 power transformer, so as you can see the Showman also installed the 45268, not only the Twin, and I was told also that these transformers were common in the Concert too and other amps. Fender was always using the parts he already had in stock before starting using new ones. You are absolutely right though, there are many variations of the same amp and, having personally compared quite a few of them, they all sound different. Some definitely sound louder and more “middy”, more blackface; some others break up a bit earlier, have more character, more bass, but less presence.
David, Often enough, for each component in the Fender product line, it’s just what was happenstantially available in appropriate quantities for any given production order period. This is borne out in the choice of the 4-terminal treble pots used during the Brownface era as well as the size of the choke used in the late professional-series Tweed amps. So the answer as to why certain transformers, chokes or even a 350k potentiometer with a 70k tap was used is because it was available, it was applicable, and it was cheap! So, even though that Tweed-era choke was huge and has a 400mA rating. It was just an “off the shelf” unit (according to Patrick Selvedge at Mercury Magnetics) that fit the application at a price that satisfied the economics of Fender production at the time.
Between the Tweed Twin with front-facing controls and the Blonde Showman amplifiers, there were no fewer than six different output transformers used—some clearly offering different impedance ratings, and others, who knows. Transformers for the Twin were not used on the Showman, and vice versa. Both the front-control Twin and the debut Showman were introduced using 6L6GC tubes, with the “A” versions later switching back to 5881 tubes (industrial 6L6GB). The different transformers were as follows: the Twin used 45268 and 45548, both with 4Ω secondaries. While the 45268 was paired with tube rectifiers, both were also used with solid-state power supplies. This raises the question—why two different transformers, especially since they started with the 45268, switched to the 45548, and then returned to the 45268, all while the output stage and speaker load remained essentially unchanged? The Showman started with the 45550 transformer (a sister to the Twin’s 45548, likely with an 8Ω secondary). The “A” version then possibly used the 45945, 45946, and eventually the 125A4A. It has been reported that the 45946 was a 16Ω transformer and the 125A4A an 8Ω transformer, but the specs for the 45945 remain uncertain. There is a lot of misinformation online about these amplifiers, so anything unverified should be treated with caution. I have personally seen all of these transformers except the 45548 and 45550. Among them, all the others are physically quite large—nearly twice the size of the classic 125A29A and 125A30A transformers used in all the Blackface Showmans. There was even another set of transformers for the very rare Showmans built to use 7355 tubes, though those are of little interest here. So, does anyone have credible input as to why there were two transformers for the Twin that appear otherwise identical, and why there were four transformers for the Showman when only three possible output impedance levels would have been needed? The 45548 and 45550 transformers were the only ones in the group that specified 6L6GC tubes; the rest specified 5881 tubes—though this distinction is minimal, as the 6L6GC is simply a higher-rated 5881 with otherwise identical characteristics. All of these amplifiers were powered by the same 67233/123P7A power transformer, which ultimately determines how much power an amplifier can produce. Any input on the specifics of these Showman transformers, or why the Twin used two seemingly identical ones, would be appreciated!
I’ve seen some with tapped tone controls. Which variation were these?
The 6G14 and 6G14A circuits are entirely different preamp topologies. The 6G14 Showman and 6G8 Twin employed the “James” preamp circuit. The latter circuit with the (A) signifier was the original precursor to the famous AB763 Blackface circuit.