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Masterpiece

3/16/2018

4 Comments

 
Or Masterpieces - which seems a bit contradictory.

In the 1920s and 1930's there were several radios that went by the name "Masterpiece". The term would seem to indicate the best of the best at least as much a one individual or manufacture was concerned. There was the exceedingly common Freshman "Masterpiece" which was rather average as far as 1920s TRF radios go. It was a good radio, but that was about it. A better name would have been, Freshman Average Radio. Then there was the Parker McCrory Masterpiece 733 From 1937  (See: https://www.russoldradios.com/unique-radios.html  3rd entry) which was a really nice 30's battery radio. It was way above average, but a "masterpiece"? Well maybe. And then there was McMurdo Silver, a guy that intended every one of his radios to be a masterpiece. By the time he got to his 5th version, the Masterpiece V, I would say the name fit very well.
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Masterpiece V on Rt. and a Masterpiece VI on the left. Both are in Clifton cabinets
I was doing the chassis restoration on a Zenith Stratosphere for a friend and fellow radio accumulator when he mentioned having several (about 7) McMurdo Silver Masterpieces. For the most part, they had been awaiting restoration since 2015. The project had been started, a lot of the parts had been rechromed, but the chassis restoration was unfinished. One thing led to another and before I knew it I was up to my elbows in Master-pieces.
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Most radio collectors do not own a Masterpiece. I would guess that  significant percentage have never seen one,   face-to-dialface.. Even more elusive are the 18-inch "Super Giant" pedestal speakers since many of them were removed along with the separate amplifier and sent off to be use for other purposes.
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Heartwarming. A  bunch of Super Giants sitting  by the fire.
Having entered into this project at the end, I never got to see the original cabinets. For that matter and as you can see, UPS just started delivering parts and pieces. And, at that, many of the speakers/chassis had been partially disassembled. It was a GRAND jigsaw puzzle.

In the photo above note the chromed pedestal on the V and VI Super Giants. They were not built that way and had been chromed along with a lot of the other parts as a matter of taste. Two were to be kept and two more were to be sold along with the matching radios. The V is on top with two VIs below.
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The Super Giant used in the MSMV has a tweeter switch that was not used on the model for the VI. The crossover is also much different.
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Underside of the main (radio) chassis of a MSMVI.
There seems to have been a lot of changes around the addition of a "MIC" circuit along with the "Phono" input for the VI. (left side of chassis)
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Underside of the main (radio) chassis of a MSMV.
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Above is the power supply/amp for a MSMV. Note the 6 tubes - 2 each 5Z3, 6J5 and 6L6s. That combination gets really HOT. Keep the power cables away from the tubes. As a note for future restorers, the MSMV amp/speaker incorporates 2 field coils in addition to the 2 chokes seen above. FC 1 has a DC resistance around 400 ohms and FC2 around 4K ohms. FC 1 is inline with the B+ to the radio and FC2 is shunted to ground. You get about 350V  to power the main chassis.
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The MSMVI PS/amp above has a 25hz power transformer which is much larger than a standard 60hz unit.
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The MSMVI power supply/amp only has 4 tubes 2 each 5U4s and 6L6s. The supply is very similar to the V less the 2 6J5s, but the DC resistance of the field coils is considerably higher than the V with FC1 at around 700 ohms and FC2 around 8K ohms. So the speakers are not interchangeable.

Another interesting thing to note at this point is that the tubes on a MSMV are all metal by Raytheon with the exception of the two 5Z3s. On the MSMVI all of the tubes are glass except the two 6L6s which may have also been glass on some units (ST bulb). At the time of manufacture the only difference between the 5Z3 and 5U4G was the base.
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MSMV topside with coil covers (shields/cans) removed.
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MSMVI topside with coil covers (shields) removed.

There are 3 more tubes on the MSMVI receiver chassis but 2 less on the PS/amp chassis for a gain of 1 over the MSMV.
Video of a MSMVI in action.
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Nice, don't you think?
4 Comments

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                         Russ Webb

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CUSTOM DESIGN BY SUE WEBB  06/2013       Redesigned by Russ Webb     Approved by Fuzzy   Updated:  Pretty much all the time, but I forget to change this date
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Photos used under Creative Commons from valart2008, rafeejewell