|Tubes||13 tubes, 1 transistor|
|Phase Inverter||2x 12AU7|
|Vibrato||2x 6CG7, 12BH7|
|Preamp||3x 6EU7 (early) 12AX7 (late)|
|Speakers||2x Oxford 12"|
|Speakers||2x 5x7" oval mid-range|
The 480 was top of the line, most feature rich amplifier manufactured by Magnatone in the new 1961-1963 Estey era.
This was a true stereo amplifier. There are two input channels, and two separate output power amp systems, each consisting of a 12AU7 phase inverter, 2 6973 output tubes, a output transformer, and a 12" and 5x7" speaker pair. Unlike a Ampeg Super Echo Twin, where the signals for an input is dedicated to the signal of the output (i.e. Channel No.1 to Output No.1, and Channel No.2 to Output No.2), the 480 mixes the two input channels to each of the output channels via the stereo vibrato circuit. It is truly a magnificent circuit.
The vibrato is the super lush stereo vibrato that is the hallmark of the Magnatone amp. Being Magnatone's cadillac amp, the vibrato uses 8 varistors, a 6CG7, and a 12DW7, and a 12BH7. This is identical to the vibrato used later in the M14 and M15 Custom Series amps.
The reverb tank was driven by a 6DR7 and recovery was handled by a transistor. Reverb signal was fed only to the output stereo No.2, and because of the phase reversal due to the extra gain stage, the speakers of output No.1 and output No.2 must be reversed.
Early 480's were fitted with 6EU7's as the first preamp tube. This was eventually replaced with a 12AX7. There were also slight tweaks to the bright switch control (see schematics.