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

[Jos Callinet]

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.

[David C. Poland]

Norman - re: the condenser block holding 7 caps - part 74 on the parts list.

Looking at the Riders info page 14-60  - it reads  7 x . 5  which I interpreted .05 , with missing 0 as a typo. And  with .05 being an oft seen value. Looking at the later Philharmonic Combo diagram I see only a couple .5 caps in the AM portion of that diagram.

You say they are 1/2 MFD.  not .05.   

I have not powered up my pointer model Philharmonic for many year. Last time I had it on my work bench may have been before I knew that was a condenser block. Was one of a number of things to check out next time on my bench. Plus I have a number of red Mallory resin sealed caps I installed  in the audio section over 50 years ago that I need to spot check for condition and possible replacement too.

[Jos Callinet]

Yes, just looking at my Philharmonic chassis makes me realize I have my work ahead of me - and an interesting question comes to mind: - which set do you think, evaluated openly, honestly and as dispassionately as possible, is the better performer over-all - the McMurdo-Silver Masterpiece VI or the E. H. Scott Philharmonic?  They were, respectively, each maker's premier offering at the time they were made and sold in 1937.   Has anyone done a side-by-side performance comparison and evaluation of these two premium radio sets?  (I've restored both a McMurdo Silver Masterpiece V AND a Masterpiece VI, which is the more complicated and later version of the two McMurdo sets.)  I know that the man, McMurdo Silver himself, was in an intensely fierce competition with his Chicago colleague, E. H. Scott, to see who could outdo the other by making "THE  BEST" radio.

Norman S Braithwaite said:

Jos:

Several of the gold dial sets have turned up but not many.  All that I know about them is that they have the same green phenolic backplate but painted gold.  When I was only aware of one, I thought that the backplate had been painted gold at sometime after the set had been purchased but a few more have turned up including one that I have.  You are correct about the tube sockets.  I recalled that the RF, oscillator, and mixer tubes use the ceramic Amphenol sockets held by spring clips and thought that the remainder were Phenolic wafer sockets as used in the AW-23 and Special Communications Receivers but that is not the case.  That will make the Philharmonic project more complicated than the McMurdo Silver one.

Norman

[Norman S Braithwaite]

Without employing any testing, it stands to reason that the Scott will outperform the McMurdo Silver in RF performance whereas the McMurdo Silver will outperform the Scott in audio reproduction.  Scott's superior RF performance is attributed to RF and IF circuit design with multiple AGC and ideal continuous variable selectivity along with RF and IF circuit construction practices employed.  The McMurdo Silver's superior audio performance is attributed to the use of a true high fidelity speaker enclosure.  As far as overall performance, weightings have to be assigned to every feature evaluated in order to develop an aggregated conclusion.  Good luck agreeing on the weightings!

Norman

[Russ Webb]

You might be interested in some of these blog posts. They can at least give you an idea of the scope of this project.

As already mentioned:

https://www.russoldradios.com/blog/77-chrome-plated-rivets

And these addressing A couple of Zenith Stratospheres:

https://www.russoldradios.com/blog/into-the-stratosphere

https://www.russoldradios.com/blog/1000z-stratosphere-poweraudio-amp

https://www.russoldradios.com/blog/another-1000z-stratosphere-resto...

These were all re-chromed.

Russ

[Jos Callinet]

Thank you, Norman - in essence, you're right in your assessment of the Scott being the superior one, in RF performance - all one has to do is LOOK at the Philharmonic's construction and the elaborate mechanism Scott used to vary the I F bandwidth, as well as study the schematic, to see that. 

McMurdo-Silver's Masterpiece VI is likewise no slouch in the quality of its construction, but it doesn't have quite the elaborateness of Scott's.

McMurdo Silver published a lengthy article describing HIS approach to building his Masterpiece VI with four fixed degrees of bandwidth. What he did, in essence, was to provide different I F transformers designed specifically for different bandwidths. He used a "Fidelity Switch" to select fixed I F bandwidths at 4, 8, 12 and 32 kHz - by dividing each by two, he arrived at the actual audio frequency bandwidth, which in the case of the 32 setting, gave high fidelity 16 kHz audio - and, conversely, the 4 kHZ setting was highly selective, allowing only a 2 kHz audio band-pass.

Silver boasted that his switched I F system worked just as well as, if not better than, Scott's mechanical continuously-variable one, and was much cheaper and simpler to build - all one had to do was rotate the Fidelity Control switch among the four settings depending on the signal being received.  But, did Silver's approach compare to Scott's design?  Surely Scott must have thought of varying his receiver's bandwidth in a similar manner - he would have saved himself the considerable trouble and expense of providing all that mechanical gearing. 

I am really looking forward to restoring my Philharmonic, because there IS something highly inspirational about the whole way Scott designed it - the superlative build quality and thought he put into his circuits, and the craftsman-like way he laid them out. 

When I asked you this question about comparing Scott's and McMurdo Silver's top-of-the-line radios, it occurred to me later that A FAIR AND JUST COMPARISON of the two would require having two certifiably completely-restored sets - each correctly wired with all the right parts in their right places - each having a set of fully-working tubes - each with all voltages at specification -  and each fully and correctly aligned.

ONLY THEN could both of them be tested together at the same time, under the same reception conditions, etc. 

A TALL ORDER!  I should have known better than to ask you this rather foolish question - perhaps a side-by-side comparison of these two radios HAS been done, but considering that both are eighty-plus-years old, they would both have to be fully restored with all life-expired parts replaced, before such a test could be run.

Norman S Braithwaite said:

Without employing any testing, it stands to reason that the Scott will outperform the McMurdo Silver in RF performance whereas the McMurdo Silver will outperform the Scott in audio reproduction.  Scott's superior RF performance is attributed to RF and IF circuit design with multiple AGC and ideal continuous variable selectivity along with RF and IF circuit construction practices employed.  The McMurdo Silver's superior audio performance is attributed to the use of a true high fidelity speaker enclosure.  As far as overall performance, weightings have to be assigned to every feature evaluated in order to develop an aggregated conclusion.  Good luck agreeing on the weightings!

Norman

[Y2K Bruce]

I agree with Norman. I have a 33 tube Philly and an MP 6 both restored by the same repairman who is the best I have found for my radios.  My opinion is the Scott is more selective and fine tunes in small stations 10 KC apart where as the MS 6 has superior sound quality. I don'y know how they did it using that super jumbo 18" speaker but it works.

[Russ Webb]

Here you go. Only problem is that nobody agrees:

http://www.antiqueradios.com/forums/viewtopic.php?f=1&t=246196

[Dave]

Agree with Norm, without doubt ! The MS execution is all about audio, why would anyone pay the premium, now and of the day, to own an expensive broadcaster. Super Giant aside, the MS thru any well executed speaker/ tweeter combo as I’ve employed, trumps the Scotts. For audio, I’d slip the Philco 37-690 between them. Many of my McIntosh contemporaries can’t believe the MS, they know tubes and audio. Anyway, fans are fans, metrics are metrics, somewhere I have the room response of MS Vs Scott, when it comes to broad baffles, you can’t beat the Giant waveguide. 
Norman S Braithwaite said:

Without employing any testing, it stands to reason that the Scott will outperform the McMurdo Silver in RF performance whereas the McMurdo Silver will outperform the Scott in audio reproduction.  Scott's superior RF performance is attributed to RF and IF circuit design with multiple AGC and ideal continuous variable selectivity along with RF and IF circuit construction practices employed.  The McMurdo Silver's superior audio performance is attributed to the use of a true high fidelity speaker enclosure.  As far as overall performance, weightings have to be assigned to every feature evaluated in order to develop an aggregated conclusion.  Good luck agreeing on the weightings!

Norman

[Jos Callinet]

To Dave, Norman and Y2K Bruce: Yes, I have fully restored both a McMurdo-Silver Masterpiece V and a Masterpiece VI, the later version, both of which I stripped down to the bare chassis the main receiver and power supply, as all of them were badly corroded and needed to be re-chrome-plated. 

I got about as deeply into McMurdo Silver's work as I could as a result, and in the process I came across literature he, Silver himself, published about both radios. He was especially detailed about the engineering circuit design he put into the Masterpiece VI, in a brochure describing in detail his reasoning behind the design he adopted for it. 

He was focused on all aspects of his set's performance, not least its audio quality - Silver faulted the use of 6H6 dual diode vacuum tubes at the point where the IF is translated into audio for amplification, asserting that a diode second detector (like the 6H6) introduces unwanted distortion into the audio, especially from when 100% modulation peaks occur - most broadcasts are severely over-modulated. McMurdo Silver used instead an infinite-impedance linear second detector, which can handle all modulation from zero to 100% without distortion, using a 6J5 triode instead of the usual 6H6 dual diode as the second detector.   

It's attention to audio detail like this that may be the reason why the Masterpiece VI sounds better than any Scott out there.  Also, I've read that E. H. Scott modified his original Philharmonic circuit design to address a problem with audio distortion caused by a design flaw in the IF circuitry.  My Scott Philharmonic is from one of the original pointer-dial model runs, so it could very well still have that design flaw, which when I tear this set down to the bare frame to have it re-chrome-plated, I will make sure to correct.

With all the effort Scott obviously put into his radios, it IS disappointing to hear (from these "radio shoot-outs" that the Scotts don't "make the cut" in audio performance!

Geeze! The sound should be stunning coming from those dual push-pull 6L6s in the power amplifier, coupled to the Scott Main Loudspeaker with its two treble speakers. Scott HAD to be very much greatly concerned with how well his radios sounded, as well as perform in their RF sections.  

After all, by naming his set the "Philharmonic" and "The Stradivarius of Radio Receivers," Scott was aiming at a very discerning buyer with highly refined musical taste and an appreciation for good sound.  One would think that a fully-restored Scott Philharmonic SHOULD sound every bit as good as either of McMurdo-Silver's late Masterpieces, the V and the VI.

[Norman S Braithwaite]

Jos:  Over-modulation was for all practical purposes not allowed in the 1930s because the practice produces "splatter" outside the legal bandwidth for the assigned frequency.  The FCC would be on the station faster than jack rabbits can multiply.  Processing and circuits that filter splatter and noise resulting from over-modulation came along much later.  Additionally whether or not distortion is produced in the diode detector has everything to do with the signal strength reaching the diode and the diode operating voltages.  Furthermore, the distortion developed in both detector circuits when properly designed pales in comparison to the distortion in source material and reproduction (speaker system).  Hence the McMurdo Silver argument that the diode detector produced more distortion in practice than the infinite impedance detector is nothing more than salesmanship.

Other than use of 1/2 of the double diode employed for audio detection being used initially optionally then normally for an impulse noise filter (spark plug noise), I am unaware of any change in the IF circuit employed in the Philharmonic or any documentation indicating the IF circuitry was changed to reduce distortion.  Please provide details when you find them.

Norman

[Jos Callinet]

Norman, thanks for your reply here.  I may know more about radios than I did before I restored my two McMurdo-Silver sets, but in all seriousness, I am still a "newbie" to radio in a large sense, as you've just illustrated. (For example, I still don't really understand how the degree to which a radio transmission signal is "modulated" affects how the signal is heard at the receiving end!) (For that matter, just what IS modulation? What role does it play?) As for where I came across the mention that there was a fault in Scott's I.F. circuit design which added unwanted distortion to the audio, I will try to find the specific article that mentioned it and share it with you here. 

What you said about Silver's use of a triode detector being nothing more than advertising flim-flam, I guess it goes to show how desperate he was to outshine Scott any way he could. Believe me, I have a lot to learn, and I am very grateful for this forum and all of you in it - I would be lost without it as I'm sure I'll find when I get into restoring my 1937 Scott Philharmonic Pointer-Dial set.

[jimmie o. ashabraner]

having rebuilt a beam of light and not having a speaker I feel for you! the speaker is gonna be a hard thing to find and expensive, so by using an output transformer from a jukebox using 6L6 tubes and a field coil speaker with a tap as the philharmonic used, I managed to use heavy wattage resistors and got the correct split and it works well. Could not wait til a speaker was available to enjoy this radio, jimmie