EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Hi,This is my Scott Philharmonic, I am trying to fix it, I would like to know where to plug in REEL TO REEL or phono, how do I switch them?ThankS! Kimi

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I saw your work, it's great! I'm still curious about the original sound, I'm looking for a 15" original speaker first, if I can't find it I'll consider an alternative, thank you!

mike hadley said:

I made a speaker substitute box for my philharmonic a few years ago, you don't have to make something as elaborate but this works

https://ehscott.ning.com/forum/topics/philly-speaker-substitute

I'm using a generic 15" PM speaker.

Mike's solution is very cool. Fashioned an outboard plug-and-play unit with 1) a stock output transformer suitable for the 6L6s matching his speaker and 2) a power resister substitution needed for the high voltage circuit the radio requires. The 2MFD cap is his crossover. And leaves his amp unchanged for easy change to a correct Scott speaker if and when he finds one.

I would side step trying to replicate the Scott crossover in favor of using the 2 MFD film cap in series with the tweeters to block low frequencies from the tweeters. This is what Scott did from 1937 to 1940 for the Philharmonic before the advent of his optional hi-fi speaker system. And what Scott did with the optional 1935-7 field coil tweeters for the AW-23 Hi Fi radio model. Determine the output transformer suitable to match the quad of 6L6's to your PM speaker voice coil (8 ohm?). There are "Universal output transformers" with multiple secondary tap combinations for today's standard speakers of 4 ,8, or 16 ohm voice coils. You would not bother replicating a cable to the receiver chassis and just let the tweeter be always ON and control higher frequencies with the receiver's treble control (far upper left). 

If your speaker is a coaxial, just treat it as a separate woofer and tweeter.  For the Philharmonic, appears Scott choose a pair of 16 ohm tweeters in series to approximately match the the 38 ohm voice coil of the standard 15 inch speaker of 1937-1940. Otherwise, nothing magical about having 2 tweeters like Scott did. Indeed, in 1941, for the Scott 18 tube model Laureate, the optional hi-fi speaker system is a 8 hm 15 inch co-axial with single center mounted tweeter with that Scott crossover. FYI the 2MFD cap acts as a crossover at roughly 2000 Hertz. The early Scott crossover in 1940 initially had a 2000 K crossover too, and later crossovers were marked 6000 Hz on the crossover.

Good luck.

I don't have the ability to make a crossover by myself, but I want to repair this broken speaker first, can this spring plate be repaired?

Regarding the chassis I'm already in the process of modifying it, I believe within 10 days, it will have a good look.

A speaker repair company would replace your broken spyder with a more contemporary version, which would be glued in place. Voice coil looks ok and would be saved and reused. Depending on which version AW-23 speaker, it would be 38 ohm or 19 ohm. But it is wrong for your Philharmonic, so consider selling as is to someone else. May be a challenge to replace the voice coil if it is damaged

I found something special, I don't know if it's a crossover, or an impedance transformer. It only has a circuit diagram, it hasn't arrived yet, hope it will come in handy, plus I have a 3-way crossover that I need to change or match.

Hi Mike,

Can you help me make a NETWORK? I am willing to pay for it. The Philharmonic is combined with my SCOTT MAGNOVOX 12" + JENSEN Q4 tweeters (they belong to 23) and I figured there must be a way to connect them as I don't want to sell these speakers.

Thanks!

Kimi

mike hadley said:

I made a speaker substitute box for my philharmonic a few years ago, you don't have to make something as elaborate but this works

https://ehscott.ning.com/forum/topics/philly-speaker-substitute

I'm using a generic 15" PM speaker.

Hi Kimi,

As Dave already mentioned unfortunately there are too many differences between the AW23 speaker and the Philharmonic,

you really would be better off finding the correct speaker or making a adapter for a more modern type,

maybe you could do a trade with another member of this site or ebay the one you have.

Mike

Thank you Mike,So I need something like PHILLY SPEAKER SUBSTITUTE right? I have a 15" 8 ohm coaxial speaker.

Kimi

mike hadley said:

Hi Kimi,

As Dave already mentioned unfortunately there are too many differences between the AW23 speaker and the Philharmonic,

you really would be better off finding the correct speaker or making a adapter for a more modern type,

maybe you could do a trade with another member of this site or ebay the one you have.

Mike

Sell your AW23 tweeters for lots of $$.  Use that money to pay someone local to build a crossover.    Not complicated stuff here.   Use permanent magnet tweeters of your choice along with the 15" you already have.  Bottom line is that you can't reasonably use those AW23 speakers, but you can use permanent  magnet speakers.   Do you have someone to restore that AM/FM remote chassis for you?  I would not be playing that thing until all the paper capacitors and electrolytic capacitors have been replaced. 

You might want to post on Audiokarma as you might get some help there, but ultimately you need someone to build this for you, and it might not be all that easy to find someone willing. 

Again, an AW-23 speaker in good condition is electrically wrong for a Philharmonic. Nor is the output transformer in the speaker pedestal or the voice coil impedance. Trying to make do with decidedly inappropriate parts is folly. Don't expect anyone here to help you on a fools errand. 

Electro magnet speakers were customary in the 1930, because magnets for PM speakers were inferior and inclined to weaken, which meant loss of audio volume. But an energized coil around the speaker's steel pole produced a  a strong magnet every time the radio was powered up.  Also, filter caps of larger capacity to control 60 cycle hum were relatively new and expensive. And the speaker's field coil (electromagnet) doubled as a choke to help eliminate 60 cycle hum in the high voltage circuit.  

Before World War 2, speaker designs, field coil specifications and voice coil impedance varied widely between companies, and from model to model for each company. Was a "Wild West" of designs by radio engineers. Further complicated by annual redesigns. Each design was unique, and today finding suitable replacements of damaged or missing speakers is difficult unless you can find the exact speaker from an identical junk radio, unless you have the technical where-with-all to modify the radio for some other speaker.

The developments in alloy steel for permanent magnets made great strides during the World War 2. So after WW2, good reliable magnets became available to industry and in turn, standardized speakers using reliable magnets with standardized  impedance on 4, 8 and 16 ohm voice coils came about. Electrically, it is fair to say most postwar 8 ohm permanent magnet speakers are interchangeable. But few prewar field coil speakers are interchangeable without rewinding field coils and trying to find a suitable output transformer satisfactory for the output tubes in combination with the non standard prewar voice coil. Trying to hook up disparate parts to see if it will work could cost you the set of 6L6 tubes and produce distortion meanwhile and maybe damage parts in the high voltage circuit. 

Per Scott's advice above, sell the valuable AW-23 field coil tweeters. Maybe someone will want to rebuild the the AW-23 speaker. Take the money and buy the output transformer you need for your PM speaker. Or watch for the correct Philharmonic speaker in good condition for a plug and play solution. For tweeters, permanent magnet tweeters are an easy resolution, wired with a 2 MFD cap to block low frequency sound from the tweeter(s).

Enough said.

I'm curious about the sound of the JENSEN Q4, so I want to make a power supply for it, how many volts does it need? Does anyone have a circuit diagram for it? And the power supply voltage of the 12-inch bass? ,thanks!

Little progress.
Bass has been restored, original voice coil.

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