Dating music man amplifiers
Music Man amps look very much like a typical Fender combo amp from the 60ies or 70ies.
Like those black-face Fenders, they have a black control plate, a silver grill cloth to protect the speakers, and are covered with black tolex.
Fender or other tube amps – including Marshalls – normally have about 450 – 550 volts here.
About 1980 Music Man changed from 6CA7 to 6L6 tubes.
The distortion that is created when a tube amp is overdriven was something invented by creative musicians or by chance when musicians tried to get as much volume out of their amps as possible.
Fender didn`t focus on the distorted sound, in the contrary, they even tried to avoid it.
Apparently this had not to do with tonal preference but with supply facilities at that time.
The tremolo effect is very effective, but also sounds different than on Fender amps.The reason was that a certain malfunction of this tube could cause severe damage to the complete output section, including a damage to the power tubes and the expensive output transformer.The amps with the new solid-state phase inverter still sound very similar to the earlier models, but are nevertheless by some considered as sounding not as warm as before. This is not realized by switching off some of the power tubes like some other manuyfacturers do, but with a reduction of the voltages at which the power tubes run.All early Music Man amp models were 2-channel amps.The reverb and the tremolo effect affects the second channel only.The rectifier was solid-state (diodes) and not a tube rectifier like in many early Fender amps.A tube rectifier causes a drop in voltage during the moment the amp is driven to maximum output.However, the circuit was rather different from Marshall.The power tubes in a Music Man amp operate at up to 700 volts at the plate.So it is not a big surprise that they used a solid-state design (ICs and transistors) for the pre-amp section.Solid -state requires lower voltage and less energy and thus causes less heat.