EH Scott Radio Enthusiasts

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New to site, Philharmonic circuit differences

Hi,

 

New to the forum, but not to E H Scott Radios! I got the bug as a kid because my dad had a Phantom Deluxe. A few Zeniths along the way but always wanted a Philharmonic.

 

I’ve narrowed my search to either an AM Beam of Light with 9 controls and the calibration dial or an AM/FM Philharmonic. Aside from the major differences of the old FM band and Volume Expander, I wanted to see if there are other circuit changes between the 2 sets, so I went through schematics and other info such as the books by Marvin Hobbs and Jim Clark. Below is a list of what I’ve found, and I’d appreciate any comments or corrections. I didn’t go into differences in tube types as that’s pretty well defined. As far as I can tell, the power amp chassis were the same, excepting possibly the rating of the power transformer.

 

AM Beam of Light

AM / FM

9 controls – Volume, Tuning, Band, Selectivity, Sensitivity, Bass, Expander, Scratch Suppressor, ??

9 controls – Volume, Tuning, Band, Selectivity, Sensitivity, Bass, Fidelity, Noise Limiter, Scratch Suppressor

Has UHF (Red) Band or Police Band

Has the old FM band

Has Volume Expander

No Volume Expander

Doublet antenna on 2 SW bands only

Doublet antenna on all 4 AM bands

Switch on Selectivity control to widen RF bandwidth

No switch

Volume pot has loudness tap

No loudness tap

Switch or pot on Selectivity control for treble cut

Separate Treble cut control

No Noise Limiter

Has Noise Limiter

2nd 6E5 for Expansion

2nd 6E5 for FM tuning

Bass Boost control with 60 & 120 Hz notches

Bass Boost but different circuit design

10kHz Notch filter

None ?

Power Amp – same as AM/FM?

Power Amp – Same as AM BOL?

Pedestal Speaker with socket for silver PM tweeters

Non Pedestal speaker with crossover box and black PM tweeters

 

Any info would be most appreciated, especially comments regarding why these changes were made.

 

Thanks! Karl

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Basically Scott did what they had to do to jamb the FM circuit into the chassis.  Something had to get cut. Your list seems to summarize it. 

Karl, I have an AM-FM Philharmonic in a Georgian cabinet and I'm a bit partial to it. The optional tweeters (Jensen PM) and crossover and the Jensen 15" woofer are outstanding. There's plenty of bass without the loudness compensation as noted. The tweeters only switch in when placed in the FM position, and I do that when playing records. Mine came with the Tauscher Sound board that I have tried with and without. A really remarkable radio. Have you read Richard Majestic's article on the Philharmonic in the Dec 2012 Antique Radio Classified? I don't agree with some of it. I'd like to hear from others concerning that.

The summary comments I have heard from some who are well versed in the Philharmonic, is that ARC article demonstrated 1) the author's lack of familiarity with the Philharmonic and restoration of same and 2) the lack of peer review of technical articles to be published in ARC.

I should have read this thread before adding comments a few minutes ago to the other current Philharmonic thread.

The list above looks pretty good. Earlier BOL Phillys continued to use the 5Z3 rectifiers for many months. BOL model continued with 6 controls plus dial and scratch suppressor button for well over a year of production. The switch to 5U4's was about 1940, about the same time the Phantom revision did the same. Also changed to using Jones plug.

Thanks for the responses! I read David's response to Ken Brown's posting and found the Scott Documents site. This is very helpful and clearly shows the differences in front panel controls, a detail I have not been able to find. It also points to the fact that the AM philharmonic schematic I was using was probably an early (7 knob pointer dial) version.

David, you mentioned you've heard summary comments regarding the ARC article - I've tried searching AudioKarma and this site, and I haven't found any discussions on the Philharmonic article. To me, the writing was more sour grapes than informative.

David C. Poland said:

The summary comments I have heard from some who are well versed in the Philharmonic, is that ARC article demonstrated 1) the author's lack of familiarity with the Philharmonic and restoration of same and 2) the lack of peer review of technical articles to be published in ARC.

I should have read this thread before adding comments a few minutes ago to the other current Philharmonic thread.

The list above looks pretty good. Earlier BOL Phillys continued to use the 5Z3 rectifiers for many months. BOL model continued with 6 controls plus dial and scratch suppressor button for well over a year of production. The switch to 5U4's was about 1940, about the same time the Phantom revision did the same. Also changed to using Jones plug.

Tom, These were conversations at radio meets, not published dialog. Although I now recall a comment in a thread on this site a few months ago. Anyway, I pulled the article to refresh myself somewhat.

I thought the tone of the article indicated his restoration effort was less than fully successful, and so the author chose to fault the engineering and choice of parts. Did he overlook a thing or two in his restoration? I think Scott and his folks knew what they were doing given the era (1930's) and the parts then available (example: wax dipped caps were the technology then and before use were tested for meeting specs, according to Scott literature).

I noted the article claimed significant distortion with a strong signal. Yet, Scott claimed far less, and his company was, after all, located in Chicago which by mid 1930's had a host of local 50,000 watt stations and furthermore, he shipped some radios to the greater Cincinnati area, home of the 500,000 Watt WLW station. I find it difficult to believe his radios failed to cope with strong local stations. And anyway, it had a variable sensitivity control and the owners manual takes some pains to explain its proper use.. The author's description of the scratch suppressor disagreed with Scott's description of its function.

But enough.

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