The Fine Things are Always Hand Made
Can it be an additional tube for this purpose? As e.g. in Philco 38-690?
The AM Masterpiece model appears to be an enhanced Super XII sporting 2 more tubes. Seems Scott "honored" the demise of McMurdo Silver by upgrading the low priced model by naming it for the former competitor.
- The AM Masterpiece ramps up the audio with 2 additional audio tubes. Both models have a 6K7 1st audio. The Super XII single 6F6 dual triode inverter/audio tube that drives the 6F6 outputs is replaced by 1) a 6J5 triode inverter plus 2) a pair of 6J5 push-pull triodes as 2nd audio driving the 6F6's. To accommodate the 2 additional tubes on the receiver, the pair of 6V6's is moved from the receiver to the separate power supply for the first 3 tube amp since the AW-15.
-- The AM Masterpiece upgrades to the same 12 inch speaker as the previous Sixteen and early Phantom models.
-- The AM Masterpiece adds a 5th red band - for ultra shortwave and TV.
-- The rare last version Super XII had already increased the controls from 4 to 6 (plus dial knob), making it look like a Scott Masterpiece at first glance, by adding a separate radio/phono switch and a variable sensitivity control.
-- The AM Masterpiece added a fidelity (treble) control (separating it from the selectivity control), and relocated the separate radio/phono switch to the stepped selectivity control.
So, a diagram comparison - seems the Super XII tapped volume control feature for low volume tone was deleted in the Masterpiece design. Appears the Masterpiece manual makes a bogus claim it is low volume "Tone Balanced" .... unless someone has an AM Masterpiece with a tapped volume control.
My example has a replacement volume control already, unfortunately. I am considering whether during my restoration to put in a tapped 500K volume control with resistor and cap like the Super XII, to make it tone balanced.
I just looked and my Masterpiece 14 is serial no NN-332.
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