38-116 Speaker match. - Printable Version

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+--- Thread: 38-116 Speaker match. (/showthread.php?tid=30)

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38-116 Speaker match. - Frank - 10-12-2005

I'm nearing completion of restoring my 38-116 code 121 chassis, and noticed an odd thing about the speaker that came with this radio. I was checking the resistance of this speaker, and a spare 38-116 code 125 speaker that I have, and found that the one that came with the radio does not match the specs on the schematic. The primary of the output transformer seems to match a 1937 116 that would use 6A3 tubes. The 1938 set uses 6L6 outputs. So what I'm thinking is that somehow, Philco just had some left over 37-116 speakers, and used them in their early 38-116 sets. So, now I'm wondering if I should swap the speaker with the other one that I have that seems to have the correct primary resistance values per the schematic? Or, could it be that the schematic is wrong. Again, my set is a 38-116 code 121.

Thanks,

Frank.

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- Chuck Schwark - 10-12-2005

I believe the 38-116 models were virtually identical witht he 37-116's, just brought out the next model year with different cabinetry. So it would make sense you'd see a "37" speaker in an early "38" version of the same "116" set.

Could have been factory or later "repair" by someone??

Unless you're getting distortions or excessive output tube current draw, I'd stick with the speaker that came with the set.

Ron may be able to confirm my suspicions......

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- Ron Ramirez - 10-12-2005

WELL...the earlier 37-116 sets used the five individual "push pin" connectors to attach the five speaker leads to the Type W electrodynamic speaker with its audio output transformer. Later 37-116 models, and all 38-116 models, used a five-contact socket at the end of the speaker cable; there is a mating plug mounted on the speaker.

The 37-116 speaker had a 360 ohm field coil; the 38-116 speaker had a 350 ohm field (almost the same).

Model 38-116 has some circuit differences from the 37-116, most notably the use of 6L6G tubes in place of the 6B4G triodes used in Model 37-116.

The audio output transformers differ; P/N 32-7717 is used in Model 37-116; P/N 32-7751 in the 38-116.

Some Philco literature mentions Codes 125 and 126 versions of Model 37-116, using Type 6A5G output tubes instead of the 6B4G tube types. I've never seen a schematic for this version, nor have I ever seen any 37-116 sets using 6A5G tubes.

Frank, you mentioned 6A3 tubes. These were used in the 1936 Model 116X, not in the 37-116. The 6A3 has a four-pin standard base; the 6B4G is electrically identical to the 6A3, but has an octal base. Also, the speaker in Model 116X is a 10-1/2 inch U-5; the speakers in Models 37-116 and 38-116 are fourteen inch Type W units.

One more thing. There were two different 37-116 sets; a "De Luxe" model with automatic tuning (the most common version), and a "Standard Tuning" model WITHOUT the automatic tuning mechanism. The "Standard" version has a conventional dial above the concentric tuning knobs.

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