The Fine Things are Always Hand Made

Scott AM Masterpiece - 1939 14 tube model

I acquired a Scott Masterpiece 14 tube model a couple years ago - ser# JJ-382 which should already be in the Kent's Scott serial number data base.

Starting restoration for installation in the a nice 1931 FADA lowboy cabinet. Really great chrome, maybe 98% receiver and the amp, too. Finally removed the bottom plate to look inside. Appears to have had an earlier extensive restoration as it is now full of blue Solar brand wax caps, a few back beauties and a bumblebee cap. Suggests a 1950-60's restoration. Also, replacement volume and bass controls. I will recap it all.

My Masterpiece owners manual says this model has low volume tone compensation - which I expected would use a tapped volume control and little circuit like the Super XII tapped at 20K does, which I just recently restored. However, the Masterpiece diagram does not show a tapped volume control. The replacement volume control has no tap, which is not unexpected.

Anyone have experience with this model with regard to the volume control? Comment anyone?

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Permalink Reply by Leonid Soloviev on February 13, 2015 at 10:42am

Can it be an additional tube for this purpose? As e.g. in Philco 38-690?

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Permalink Reply by David C. Poland on February 13, 2015 at 1:48pm

Hello Leonid,
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.
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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.
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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.