[49Stude63]

On chassis variations was it normal for Philco to add a tube? I picked up a 37-11 which when I look at Chuck's site at the tube manual it shows 9 tubes, I can see the sticker on the radio and it shows 10 tubes, I can count 10 tubes. I know that there were design variations in chassis versions but was it common to just add a tube?

[Chuck Schwark]

The 37-10 used 9 tubes. The 37-11 is a 37-10 with the extra tube.
Generally speaking it was not just add a tube, but also changes in components, improvements to a part with a new part number, re-wire a circuit and/or eliminate a component(s), etc.

See this Service Tip from my site:

PHILCO SERVICE HINTS & TIPS - NUMBER 35
Philco Code and Run Numbers Explained


Production Change Notes were issued for these Code and Run Number changes. I provide these notes (when applicable) in the info packets I provide.

The 1938 Tube Manual I have on line only covers up through the 1938 models and may not reflect subsequent Run and Code changes in those models.

[Ron Ramirez]

Chuck, I think "Stude" is referring to this page on your site:
http://www.philcorepairbench.com/tube/tcomp4.htm

in which you have Model 37-11 listed as having 9 tubes. The 37-11 actually has 10 tubes. The PDF on your site showing the 37-11 tube layout is correct, showing 10 tubes.

Just one of those things...Lord knows I make more than my share of errors...

[49Stude63]

I was looking at the list and not the pdf of the tube layout, if I had I would not have posted since the pdf agreed with the radio. I guess I also expected to see the 37-9/10/11 to follow the 38-1/2/3 format where each one has a different tube count but that is not the case with the 37-9/10. I guess I have a decent collection of the 37/38 models now, a 37-11, 38-2,4, 116

[Chuck Schwark]

D' oh!

Will fix the typo asap. Forest and Trees Effect . . . .

Mea Philca


[EDIT]: Tube Complement Page fixed now, I hope.

[49Stude63]

Chuck I just figured it was a code change so I wonder if that was normal, normally with the codes one just thinks of some type of engineering change but adding a tube seems more like a re-design. This was one of the magnetic tuning model and they basically have the same tube count, added one on the 37-11, so I guess it was more cabinet styling than chassis for the sales pitch. Ron how common are the 37-11's, I am stuck up here in Mich, without my book.

[Ron Ramirez]

Stude - There are two versions of the 37-11; 9,400 of the second version (which you now have) were made. 5,900 of the first version were made.

According the the Service Bulletin for Model 37-11, which also covers Model 37-10, the only difference between the two is in the 2nd detector-1st audio circuit. Model 37-10 has a 6Q7G performing both functions. Model 37-11 has a 6J5 second detector, connected as a dual diode (the grid is used as one of the diode "plates"); and a 6K5G is the 1st audio amp.

Philco would pull this trick several times in later years; having a lesser model using one tube as 2nd detector and 1st audio, and a higher priced model using two tubes for these functions. Some examples include Models 39-25 and 39-30; 40-150 and 40-155; 40-180 and 40-185/190; 40-195 and 40-200/201; 41-250 and 41-255; 41-280 and 41-285/287; 41-295 and 41-300/315.