[theblurrrr]

I just bought a console at a local auction--it has no model number label. I've determined it is either a 660 or 665, but I cannot tell the difference in my resources. Ron's book even says they used the same cabinets--How can I determine which version it is??

Thanks in advance!

[Ron Ramirez]

Blurrr,

If you bought a 660L or 665L, they used the same cabinets. But if you bought a 660X or 665X, their cabinets differ. View the differences in my online Photo Gallery.

660X: http://www.philcoradio.com/gallery/1936a.htm#ap
665X: http://www.philcoradio.com/gallery/1936b.htm#al

The tube layouts are the same on each, and both use ten tubes and have four bands, so you would need the Service Bulletins for each (available from Chuck) to know exactly what you have, if you had a 660L/665L.

Scroll down toward the bottom of each page to see these models.

I have yet to see a 660L or 665L. But the 660X and 665X sets are out there and not terribly difficult to find.

Take a look at the pictures in the Gallery and let us know what you determine.

[Chuck Schwark]

T. Blurr,

There are a couple subtle circuit differences between the virtually idnetical 660 and 665 chassis'.

On the 75 DET tube in the 660, both diode plates are tied together, but in the 655, there is a small value cap tied across the two plates.

Also, in the 660, the Shadow Meter has a 2,000 ohm resistor in parallel with the Shadow Meter coil. The 665 has no such shunt resistor on the Shadow Meter circuit.

[theblurrrr]

Thanks for the information. I had looked at those pictures and others elsewhere, but found that some of them had labeled the 660 as a 665 and vice versa, so I was confused.
Using these pictures, I can see that I have a 660X. Honestly, I like the 660X cabinet better.
I printed the schematics for each and noted the differences between them. I don't know if the 665 chassis was actually superior or just less expensive to build, as I have noted the deletion of several parts on the 665 chassis. At least my experiences with the other Philcos I have will help --I have a 91, a 16B, two 37-116s, a 38-116 and a 38-690.

[Chuck Schwark]

TB,

Remember too, that there are many Production Change Notes for these two models as well as the orignal service bulletins -- parts changed added, removed, etc., depending on which production run you have.

[Ron Ramirez]

The 660 and 665 are very similar electronically to the 1936 Model 116B chassis; they even used the same chassis pan.

They differ in frequency coverage and, of course, the 116 uses eleven tubes while the 660/665 uses ten. The 660/665 uses a single tube, a Type 75, as 2nd detector-1st audio; this job is handled by two separate tubes in the 116 - Type 37 as diode-connected 2nd detector, Type 77 as 1st audio. The 116 uses a five-point tone control; the 660/665 has a four-point tone control.

The 660/665 has a large, round metal hole cover over a hole cut for a Type 77 tube socket which was used in the 116B. The 660/665 wave trap adjustment is underneath this hole cover.