EH Scott Radio Enthusiasts

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SCOTT PHILHARMONIC MODEL XXX - Serial No. D-751 = MUST TEAR DOWN TO FRAME TO RE-CHROME CHASSIS

am the proud new owner of a Scott Philharmonic Model XXX, Serial Number D-751 on main chassis. Bought this chassis and its companion power supply (came with NO speaker or cabinet) on eBay from a seller in California (who knows nothing about old radios other than that they're interesting old items worth selling on his eBay site). I opened up the main receiver chassis, which arrived by FedEx today, Saturday, February 17, 2018, and it appears NEVER to have been worked on! NO replacement parts in it whatsoever, nor ANY evidence of work done. The chrome on the main receiver chassis is "ROUGH" at best - well past the "clean it up with chrome polish" stage - so this chassis is going to have to be completely re-chromed, including all the tube shields and coil covers, some of which have quite badly pitted chrome plating, but none are missing or dented.
I am faced with no less a task than to completely disassemble this radio down to the bare frame and START OVER, salvaging and thoroughly cleaning every good part for re-use. After I get the main and power chassis back from my chrome plating shop, I will have to basically reassemble this complex radio from scratch, treating it as I would, a "kit," using of course all new wiring and resistors and capacitors. I will have to meticulously follow Scott's original factory layout and workmanship, so I'll be photographing every section of the underside of this as-of-now UNTOUCHED radio BEFORE I take it apart and then later on, VERY carefully put everything back as closely as possible to as the factory did it. It is the ONLY way I can get at the main and power chassis to free them up to have them re-chromed. IF I can take this radio apart without damaging any of its precious and irreplaceable component parts and reassemble it CORRECTLY, according to the E. H. Scott Radio Laboratories' Schematic, I will be very intrigued to see just how well this radio can be made to work, if it's supplied with all good tubes, and I am able to align it according to Scott's own servicing instructions, which I got together with the complete schematic (for the Model Philharmonic XXX, which is a non-FM, non-Beam of Light set); those arrived on the scene later, around 1939 or 1940 / 1941. I think my radio dates from 1937, if its serial number can be traced to a factory listing.

I will be very much interested to hear from anyone else of you in this E.- H. Scott group who have had to rebuild your set from the ground up, as I am about to do with mine, in order to strip the chassis bare to be re-chromed. It's not enough simply to re-chrome the easily removable parts - I have no choice but to do this to both my power and main radio receiver chassis, to make this radio right again.

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Something that you might be interested in,  I did some software modeling of the bass boost circuit a few years ago.  Particularly in regards to the 60 Hz filter notch.  The post of the results are here:

http://antiqueradios.com/forums/viewtopic.php?f=6&t=278370

Hi, to Scott Seickel - I thank you most heartily (as I do all the others who have offered me their knowledge and suggestions) for giving me such a rich and valuable gold-mine of information! 

There is a lot for me to consider as I tackle restoring my complete and long-forgotten Philharmonic Pointer-Dial set.  If I am going to go to all the trouble of stripping my two chassis to the bare ground and start completely over, cleaning and servicing every re-useable component in the process, and giving the radio an entirely new set of the best wire, resistors and capacitors I can lay my hands on, plus the best NOS tubes I can find and test on my beautifully restored and calibrated Hickok tube tester - I want my Philharmonic to WORK as well as LOOK its best!  

As you've shown me through your in-depth analysis of the bass-control circuit with its pair of chokes and associated capacitors - all  of which for now are "unknown quantities" buried in the depths of my chassis, you have given me much to think about and work on. 

A related thought occurs to me - why not eliminate all filament-induced 60-Hz hum by building a full-wave, heavily-filtered rectifier to serve ALL the 6-volt tube filaments in this radio, giving them battery-grade 6.3 volts D.C. ?  Then I wouldn't have to find tubes with spiral-wound filaments, etc. I know I'd have to build a separate full-wave D.C. power supply for the filaments, using a tapped-secondary transformer and set of diodes together with adequate filtering.  

I suspect many here might suggest I am "gilding the lily" by doing this, but is supplying the filaments with D.C. an idea worth considering?


Scott Seickel said:

Something that you might be interested in,  I did some software modeling of the bass boost circuit a few years ago.  Particularly in regards to the 60 Hz filter notch.  The post of the results is here:

http://antiqueradios.com/forums/viewtopic.php?f=6&t=278370

Hi, Scott - I have accepted your friendship request - thank you.   I'm sorry you had such poor results from your plating shop with the underside of your receiver chassis!  The plater I use knows what they're doing! That's why my McMurdo-Silver chassis came back to me beautiful on the top side with the chrome done to perfection, and the underside done to perfection as well, with only a copper and nickel finish, so that I could solder my ground points to the chassis. I told my plater what my needs were and they understood and worked accordingly.

They are NOT cheap - as their motto posted in their front office says, "Cheap Work ain't Good, and Good Work ain't Cheap!"  They're perfectionists, and they have a fine reputation rechroming antique classic automobile parts, which have won First Prize in many Antique Car Concours contests, like the one held at Pebble Beach in California every August.  Here's the link to their website - they're called "The Finishing Touch," and you won't go wrong using them:  http://www.thefinishingtouchinc.com/

I had to have them re-do work done by another plater, who made a total mess of aluminum coil cover cans on my Masterpiece VI - they just about destroyed the aluminum - it was all my plater could do to salvage them and give them a PROPER chrome job - but  they told me DON'T try to chrome-plate aluminum pieces if at all possible.
Scott Seickel said:

Hi Jos.  That is a beautiful job you did on those radios.  Thank you for the pictures. 

That is how I want the bottom of my Philharmonic to look, unfortunately, it came back with copper showing and spots of chrome flash everywhere and it looks like a mess.  While the top looks good, I need to send my chassis out to a more competent plater so the chassis can be redone to look like yours.  The plater said that all the holes in the chassis gave him a hard time with the plating process.   Funny thing is that this plater did an excellent job on the tube shields which by all accounts are harder to do.  What plater are you using?

As for the tube shields, I would definitely have them rechromed.  They were chrome originally and chrome on aluminum is fine.  Polished aluminum will never look correct, plus even if polished, their shine will fade as the aluminum oxidizes.  Chrome is done on aluminum car wheels all the time and it has reasonable durability if done correctly. 

I also sent you a friend request on this forum.  Please accept it so I can send you a private message. 

Jos,

Throwing in my 2c late here as I've had my nose in other projects.

IMO, there are a number of steps you can take to insure that your Philharmonic is performing as it should "after initial rebuild and alignment". Too many guys leave it here.

The alignment procedure for the XXX has a section that describes how to reduce hum. Go through it.

Try to have a number of NOS tubes on hand extra for substitution. 1st and second audio tubes need to have good heater cathode isolation to keep hum low. It's also good to remember that the set came from the factory with not "good" testing tubes but new. I try to use high performing (85 to 90% new gm if possible) Any gas reading is a negative.

It also helps to match the output tubes withing 5% or so for minimum hum contribution and distortion.

I use 1612 type tubes for the expander stage. They are 6L7 equivalents with low noise and microphonics.

Grounds must be tight and tube sockets must be snug while switches should be clean with proper tension on contacts. you should be able to "drop" the front of the chassis two inches or more while playing and hear nothing change.

It should be pointed out that such a radio with so many gain stages can be subject to noise problems. I typically spend a day or more swapping tubes and retesting and retuning for sensitivity. (Especially RF, mixer and oscillator). You should be able to get down into the low single digits in uV. If you don't have the equipment to test for it, I'd advise investing in a good quality digital sig-gen with a wide range attenuator. The difference in performance and sound is remarkable.

The IF strip can be peaked as described but it's best to sweep it and align while checking at various bandwidths and input levels. This can take a lot of time!

I don't have issues with my radios overloading but it is important that the 6B8s used in the AVC circuits are high functioning if not new with the transformers aligned carefully.

Set up a decent antenna. These radios work with an ice pick in the antenna terminal but are designed for a longwire.

And then we have source considerations. Our post WWII channels give us about 5 kHz of audio response on a good day. To really hear what these sets were capable of, I use my Fluke 6060 sig. gen. with a clean audio source into the mod jack. This feeds a long wire running across my basement. I tune to the top of the broadcast band where it's quietest. With a set of tweeters, you can rival FM broadcast.

best of luck, Bill

Hi, Bill - Thank you! Excellent suggestions!  It's exciting to know how good these radios from our past can be, even in 2018 and beyond.  They are a real testament to the smarts, skill and enthusiasm Scott and his high-end peers had for and applied to the design of their radios. I will be sure to keep your suggestions and recommendations very much in mind as I do my restoration.  I'm SO looking forward to doing what I can to do full justice to this precious and wonderful old radio.



Bill Liers said:

Jos,

Throwing in my 2c late here as I've had my nose in other projects.

IMO, there are a number of steps you can take to insure that your Philharmonic is performing as it should "after initial rebuild and alignment". Too many guys leave it here.

The alignment procedure for the XXX has a section that describes how to reduce hum. Go through it.

Try to have a number of NOS tubes on hand extra for substitution. 1st and second audio tubes need to have good heater cathode isolation to keep hum low. It's also good to remember that the set came from the factory with not "good" testing tubes but new. I try to use high performing (85 to 90% new gm if possible) Any gas reading is a negative.

It also helps to match the output tubes withing 5% or so for minimum hum contribution and distortion.

I use 1612 type tubes for the expander stage. They are 6L7 equivalents with low noise and microphonics.

Grounds must be tight and tube sockets must be snug while switches should be clean with proper tension on contacts. you should be able to "drop" the front of the chassis two inches or more while playing and hear nothing change.

It should be pointed out that such a radio with so many gain stages can be subject to noise problems. I typically spend a day or more swapping tubes and retesting and retuning for sensitivity. (Especially RF, mixer and oscillator). You should be able to get down into the low single digits in uV. If you don't have the equipment to test for it, I'd advise investing in a good quality digital sig-gen with a wide range attenuator. The difference in performance and sound is remarkable.

The IF strip can be peaked as described but it's best to sweep it and align while checking at various bandwidths and input levels. This can take a lot of time!

I don't have issues with my radios overloading but it is important that the 6B8s used in the AVC circuits are high functioning if not new with the transformers aligned carefully.

Set up a decent antenna. These radios work with an ice pick in the antenna terminal but are designed for a longwire.

And then we have source considerations. Our post WWII channels give us about 5 kHz of audio response on a good day. To really hear what these sets were capable of, I use my Fluke 6060 sig. gen. with a clean audio source into the mod jack. This feeds a long wire running across my basement. I tune to the top of the broadcast band where it's quietest. With a set of tweeters, you can rival FM broadcast.

best of luck, Bill

I have a gold-dial Zenith 12S475 and everyone tells me it is actually blue that just faded out to gold.  I have trouble believing that because if the gold color is "just faded blue," it's one of the most uniform color fades in all of history, not a hint of bluishness or greenness anywhere.  But people I've asked insist it was blue originally.

So I guess my question is whether there's any chance the gold ones are actually just green ones, that faded to gold?  Proposing the hypothesis even though I don't half believe it myself.



Jos Callinet said:

Thank you, Norman, for letting me know about this interesting fact about the unusualness of the gold dial - I wonder if anyone knows why and for whom, perhaps, Scott might have reserved their gold dials?  Maybe Scott just gave gold a try and then decided against using it on their dials, the majority of which I assume are green?  Do you have any more information about the gold dials versus their green counterparts?

That is exactly what I had thought about the gold dial Scott Philharmonic until I procured one.  The gold is paint over the green phenolic.  I am now convinced it is original because the paint is old with a "shadow" of the dial scale evident and several disparate having been found.

Norman 

@ palegreenthumb - I'm not sure a parallel can be drawn or inferred between what Scott did with his dials and what Zenith did, with theirs. You do raise an interesting point, however - maybe there was a brief competitive flurry of interest among radio manufacturers in producing radios with gold dials, and both Scott and Zenith jumped on that bandwagon. As for them fading from blue (Zenith) and from green (Scott) - Norman here says Scott's gold dials still have the green phenolic backing behind them, so fading is evidently not an issue with the Scotts.

palegreenthumb said:

I have a gold-dial Zenith 12S475 and everyone tells me it is actually blue that just faded out to gold.  I have trouble believing that because if the gold color is "just faded blue," it's one of the most uniform color fades in all of history, not a hint of bluishness or greenness anywhere.  But people I've asked insist it was blue originally.

So I guess my question is whether there's any chance the gold ones are actually just green ones, that faded to gold?  Proposing the hypothesis even though I don't half believe it myself.



Jos Callinet said:

Thank you, Norman, for letting me know about this interesting fact about the unusualness of the gold dial - I wonder if anyone knows why and for whom, perhaps, Scott might have reserved their gold dials?  Maybe Scott just gave gold a try and then decided against using it on their dials, the majority of which I assume are green?  Do you have any more information about the gold dials versus their green counterparts?

Jos -

This thread has taken on many interesting sub-topics along the way. When restoring a set, there are many thoughts on originality vs. ideal operation. Some comments in this thread have addressed circuit modifications to enhance performance. It is certainly true that we know a lot more today than in 1937 when the set was built, and there are things to be done to enhance performance. 

On the flip side, if we stick to originality, we may sacrifice some performance, but maintain the original look and character of the set. I liked Bill's thoughts because he highlighted ways to enhance performance without altering the set with modern updates. 

Finally...Scott did make modifications along the way in the 1930s in all his sets. Which of these updates should be applied to your set? 

I don't have an answer for you. For myself, I try to maintain as much originality as possible, sometimes incorporating Scott sanctioned modifications where appropriate (example: I had a 23 that had been back to the factory for repair and clearly had undergone updates. I felt it appropriate to maintain those changes.) I go to the trouble of "re-stuffing" capacitors in rare, historically valuable sets to preserve not only functionality but appearance as well. Every set is unique and you'll have to consider and balance all your work to achieve what I am sure will be a superb restoration.

Kent

I suppose I was viewing it more as an issue with the paints, than the radio manufacturer.  I remember in the 1980s when any red car from the 70s or earlier had faded to pink, because the red paints oxidized so quickly.  I doubt Zenith or Scott formulated their own dial paints...they sourced paints from the paint industry. If the blue and green dyes of the day were not stable, then any manufacturer using them, whether radios, clocks, appliances, or cars, would have had similar issues with color instability.

Gold dial radios have survived admirably.  I don't know how they made their metallic gold colorants in the '30s, but those don't seem to have had any stability problems.  *Many* other colors have changed over time, with many drifting toward a muddy yellowish-brownish-goldish (non-metallic) color.

Just look at the under-chassis wiring. It all used to be the same as modern wire colors.  Now much of it is just sort of brown and you can't tell what was what.  That's not paint, but its a similar effect.



Jos Callinet said:

@ palegreenthumb - I'm not sure a parallel can be drawn or inferred between what Scott did with his dials and what Zenith did, with theirs. You do raise an interesting point, however - maybe there was a brief competitive flurry of interest among radio manufacturers in producing radios with gold dials, and both Scott and Zenith jumped on that bandwagon. As for them fading from blue (Zenith) and from green (Scott) - Norman here says Scott's gold dials still have the green phenolic backing behind them, so fading is evidently not an issue with the Scotts.

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