New Member AM Phantom Deluxe second issue

[Kirk Spalinger]

Scott Enthusiast members

 

Second issue:

 

My second issue with my newly acquired AM Deluxe is a previous owner cut out the noise suppression circuit in the receiver. This was purposely done by someone that new what they were doing. The wires were snipped right at the terminal solder points so they could be easily reattached.  There are three wires cut running to 6H6G noise limiter tube, there is also a red wire cut at the IF that leads to tube 6B8G part of the scratch suppression circuit.

 

I know this circuit cuts high frequencies at low volume for recorded music, maybe this circuit was causing a problem when playing a record? Unless the suppression switch doesn’t work you should be able to turn off the suppression circuit.

 

My question is should I leave it as? At least until I can test the set?

[David C. Poland]

Before trying to address that issue, first the receiver and amp should be extensively recapped. Get the radio playing well before trying to deal with the dynamic scratch suppressor circuit.

I just completed restoration of a Phantom Deluxe. There is a rectangular metal box attached to the inside middle partition - there are 4 caps inside to replace - I cut it open with a drummer tool and melted the tar inside for extraction of the old caps. Also deal with the 4 section filter cap near by - I rebuild mine and reinstalled it. The 3 diode assemblies also have caps to replace, too.

[Kirk Spalinger]

Hi Dave

I thought about recapping before I even warmed it up, although not beyond my capacity, I would need help with the caps since this is not my area of expertise and would not want to use incorrect type caps. Not sure has anyone put together a list of caps needed and or have a source for all these caps?

I visually inspected both receiver and amp and besides the suppressor circuit nothing was amiss, it appears to be in very good shape.

[Kent King]

As Dave said, you should replace the paper capacitors throughout the set. Go to Antique Electronic Supply (or any of the folks that sell new caps), and buy a bag of about 25 .047ufd@630v caps. Those will replace any of the .05 caps in the set, whether they are 200v or 400v. A great universal replacement. You may find a few other values in the set (.25ufd or maybe some .01ufd): look over the schematic (found here in the Scott Info Archive) and order the other odd values you might need. Again the 630v standard units work universally. The schematic will also tell you what filter caps to get. Remember, with caps - the voltage rating should always be equal to or higher than the old unit. 

[Kirk Spalinger]

Kent King said:

As Dave said, you should replace the paper capacitors throughout the set. Go to Antique Electronic Supply (or any of the folks that sell new caps), and buy a bag of about 25 .047ufd@630v caps. Those will replace any of the .05 caps in the set, whether they are 200v or 400v. A great universal replacement. You may find a few other values in the set (.25ufd or maybe some .01ufd): look over the schematic (found here in the Scott Info Archive) and order the other odd values you might need. Again tGhe 630v standard units work universally. The schematic will also tell you what filter caps to get. Remember, with caps - the voltage rating should always be equal to or higher than the old unit. 

[Kirk Spalinger]

Great information Kent, Thank you!

[Thomas Day]

Kirk; Until you can find the correct speaker, check out Antique electronic Supply as mentioned for the capacitors. They also carry a line of Hammond (not the organ co.) transformers and have one that will match 6L6 tubes to any speaker.  The field coil can be subbed with the proper value power resistors. You can use the speaker you have, if you can sub in the correct value of power resistor to go with the field coil you have. Check the schematic for field coil values and current rating.  You also could carefully remove  the original speaker socket and replace it with a different one, keeping the original safe with the amp, to reuse when you find the right speaker.  All of the capacitors need to be changed, including the electrolytics on the chassis and the power supply.  

This should be great radio when you are done.  

Thom

Kirk Spalinger said:

Great information Kent, Thank you!

[David C. Poland]

Thomas - Hammond makes some universal output transformers. At several watt ratings like 2, 5 10 and up to 15 watts. With 6 output lugs covers a lot of tube/voice coil combinations but max out at about 16 ohms. Radio Daze also carries some Hammond output transformers.  But no combination appears right for the 38 ohm voice coil of some of the speakers Scott supplied for some models. So when Kirk finds the right 12 or 15 inch Scott speaker  with the right tapped field coil, hope the attached transformer is good. A 15 watt rated output transformer is shy of the capability of the 6L6 amp for the Phantom Deluxe. The speaker he came up with ought to work out well by addressing the addressing the field coil issue per above.

I found out the 15 watt Hammond 125-E has room to add turns to the secondary on the outside of the coil inside the the iron core and exterior frame. Which is what I did for a 14 tube Scott Masterpiece (after some research) to reduce the primary to secondary ratio.  There are other more expensive Hammond transformers for higher watt output with suggested output tubes, but I haven't identified a candidate for p-p 6L6 to match  the 38 ohm voice coil in some Scott speakers.  

[Kirk Spalinger]

Hi Thomas, thank you for your input, I started a spreadsheet and listed needed capacitors for the receiver and amp. Most of the schematics for the Phantom Deluxe are difficult to read when blown up enough to read written cap values. I went back to both receiver and amp to look at a couple values I could not make out on the schematic and could see two electrolytic caps soldered underneath one of the multi-section cans on the topside of the amp. That disconnected filter was the one in the middle with a value of 30,30 mfd 450V, weird thing is I believe they used the outside filter can with a value of 20,20,20,20, wired three caps together for the 60 mfd circuit for the disconnect can. Then the added caps underneath with a higher value wired to the circuit for the outside can.

I will take some picture and post them, I know a lot of you are SME's subject mater experts on these old radios and will guide me straight.

Dave, you are way above me adding turns to a coil to increase output, that is why I am glad to be part of this group, (I have a go to when I need help). This will be my first go at a recap. somewhat excited to do it but want to understand what I need and what changes were made before I order the caps.

[David C. Poland]

Kirk - Don't concern yourself now with the possible need for output transformer until you actually need one. If and when, then I can give you detail on what I did to modify an output transformer.. 

Meanwhile, you appear to have a serviceable 15 inch speaker with output transformer from another radio which used 6L6 output tubes - how convenient. Permanent speakers were not so good through the 1930's because the magnets tended to loose strength. Hence, good radios performed better with field coils energizing the iron pole piece for magnetism and dropped voltage in the process. A speaker field coil has two purposes:1)  energize the magnet and 2) help smooth out the pulsating B+ from the rectifier tubes. 

Your issue now is to deal with field coil issue of the speaker you have now, until you find the correct Scott speaker. 

Think of a tapped field coil as two coils in series, thus:  515 ohm plus 410 ohm = 925 ohms per specs.

You already have a 500 ohm field, which is enough to energize the the magnet for the speaker to operate.   Think  of the 410 field coil as missing for which you will substitute a 400 ohm 10 watt (or larger wattage) resistor, in order to satisfy the electrical requirements of the Phantom Deluxe power supply. I would not be overly concerned that your 500 ohm field coil plus a 400 ohm power resistor only adds up to 900 ohms. You are trying to provide a serviceable speaker so you can test out your radio after recapping and then to be able to detect any other issues to address. Remember, your Scott radio was designed to function well on house voltages ranging from about 100 volts to upwards of 130 volts AC and so the B+ voltages might vary widely in the home.

Also, the Phantom of 1938-9 is not the same as the Phantom Deluxe of late 1939 through 1941. Be sure you are referring to the one using the amp using two 6L6's and two 5U4 rectifiers.

[Kirk Spalinger]

David

I wanted to reply now that I am ready to address the speaker.

I recapped the receiver and the amp, I found a couple of cracked resistors and those paper caps hiding in the metal cans under the chassis.

Three issues you mentioned I needed to correct for the speaker was 1. Need 400 Ohm 10w power resistor to run in series with field coil. 2. You mentioned running a  2 mfd cap in series across the voice coil for the tweeter. 3. Find a Scott speaker 7 pin connector or one that will work. Is this correct?

David C. Poland said:

Kirk - Don't concern yourself now with the possible need for output transformer until you actually need one. If and when, then I can give you detail on what I did to modify an output transformer.. 

Meanwhile, you appear to have a serviceable 15 inch speaker with output transformer from another radio which used 6L6 output tubes - how convenient. Permanent speakers were not so good through the 1930's because the magnets tended to loose strength. Hence, good radios performed better with field coils energizing the iron pole piece for magnetism and dropped voltage in the process. A speaker field coil has two purposes:1)  energize the magnet and 2) help smooth out the pulsating B+ from the rectifier tubes. 

Your issue now is to deal with field coil issue of the speaker you have now, until you find the correct Scott speaker. 

Think of a tapped field coil as two coils in series, thus:  515 ohm plus 410 ohm = 925 ohms per specs.

You already have a 500 ohm field, which is enough to energize the the magnet for the speaker to operate.   Think  of the 410 field coil as missing for which you will substitute a 400 ohm 10 watt (or larger wattage) resistor, in order to satisfy the electrical requirements of the Phantom Deluxe power supply. I would not be overly concerned that your 500 ohm field coil plus a 400 ohm power resistor only adds up to 900 ohms. You are trying to provide a serviceable speaker so you can test out your radio after recapping and then to be able to detect any other issues to address. Remember, your Scott radio was designed to function well on house voltages ranging from about 100 volts to upwards of 130 volts AC and so the B+ voltages might vary widely in the home.

Also, the Phantom of 1938-9 is not the same as the Phantom Deluxe of late 1939 through 1941. Be sure you are referring to the one using the amp using two 6L6's and two 5U4 rectifiers.

[David C. Poland]

Yep - Finding a speaker plug will be a challenge. The standard  7 pin plug or tube base has two fat pins side by side being pin #1 and #7 ( counting clockwise from prong side).

The speaker fat plug pins are #1 and #4 - May have to make one. Best to find proper speaker with the cable and that plug attached. Either 12 and 15 inch speakers exist for the Phantom Deluxe (or Philharmonic) will suffice for the amps using 6L6's.

[Kirk Spalinger]

David

 

I completed the recap and on the radio and amp and finished adding the 10 watt 400 ohm power resistor in series with the field coil, I am now showing 887 ohms across the coil, I also added a 2uf cap in series with the tweeter as you suggested.

 

I am a little confused matching the correct pinout from the amp’s speaker socket to the speaker. Looking at the schematic, (correct me if I am wrong) speaker socket pin 1 is ground and pin 4 is to the field coil (900 ohms), Pins 5,6 and 7 are to the output transformer. Are pins 2 and 3 not used in this case?  There are five wires running from the speaker amphenol connector to the speaker: one to ground, one to the field coil and the other three to the output transformer. There is a jumper on pins 2 and 3 of the speaker amphenol, I assume they are not used?