The Fine Things are Always Hand Made
I just replaced the two 2.35 uf caps in the late 6khz crossover chassis on my AM/FM Phil. The caps are embedded in tar inside the crossover, so there is no visual of the actual capacitance. In fact there are three caps in parallel that make up the 2.35uf for each. I didn't hear any difference after the replacements. The cable that connects switching in the tuner to the crossover is actually a double pole that switches the tweeters in and out and unfortunately that cable is not shown on the crossover schematic in Riders page 14-12. I'm trying to draw an actual schematic showing the cable connections in the crossover but it's a challenge!
Norman, Interesting you had a manual switch to cut out the tweeters on that Philharmonic.
I just color coded Kent's crossover diagram from above in this thread and researched Rider diagrams.
G plug - I stand corrected: is a large 4 pin plug to the 115 AC socket on the amp to power 35Z3 which supplies
B+ to tweeter field coil(s).
Obstructed "G" legend would read "Amplifier Plug".
E plug is the small 4 wire plug to the receiver - carries audio to receiver and back to speaker voice coils.
The FM combo Philly diagram (Riders Vol 14 pg 5,6, dated October 1940) shows the "Network Switch" as located on the band switch to control the tweeters "on" for FM only. The Revised Laureate diagram Riders vol 15 pg 5,6 also shows the Network Switch ganged on the band switch to control the tweeters for FM only.
Riders Vol 14 crossover diagrams show permanent magnet tweeters with 2 pin plugs. In contrast, Kent's crossover diagram shows 4 pin tweeters and the 35Z3 which matches my crossover. So, mine feeds B+ to the tweeter field on tweeter pins 3 & 4. My crossover came with the my Laureat's co-axial 15 inch with center mount tweeter. My crossover has a 2nd 4 pin tweeter socket, so, I suspect there are some late production 1941 Phantom and Philharmonic models with field coil tweeters as well.
When I get to the restoration of my AM only remote control BOL Philharmonic, I wonder what I will find on the band switch. This AM only Philharmonic receiver has the same small Network Switch socket I now associate with the ganged band switch to control tweeters.
Evidently, your crossover has no rectifier and has 2 pin tweeter sockets. I also have this version crossover (from an FM Phantom - eBay). Case bottom says 6KC. Just now opened it up for the first time, several caps (more than two from what I can see) potted in tar on the case bottom.
In contrast, the caps in my crossover with 35Z3 are not potted, They are 3 separate capacitors -
two are large 2.36 MFD at 400 volts wax caps in the voice coil circuit and one smaller size 80 MFD @ 150 V electrolytic for B+ for the tweeter field coil as shown on Kent's diagram.
Kent's diagram matches nicely with the cable to the receiver Network Switch on the late receiver diagrams I just described, so should be a good guide for you to draw yours without the 35Z3 circuitry. Incidentally, when no extension speaker is used, the extension speaker socket has a dummy plug with wire bridging pin 3 to pin 4 to continue the audio circuit onto pin 4 of the small chassis cable plug.
Just pulled the bottom off my crossover. It also matches Kent's schematic and Dave's' description. I don't have any field coil tweeters so not sure if I will be using this piece.
David, did you notice on the schematic that Kent provided of the 35Z3 version that socket (E) from the "chassis cable" most likely serves the same purpose as the FM Phil tweeter cutout switch cable.
It's curious that the AM/FM Philly schematic show the tweeter cutout switch and cable but the network schematic (for PM tweeters) in Riders 14-12 does not show this tweeter cutout provision. Conversely, Kent's 35Z3 schematic shows a socket (E) for the tweeter cutout cable, but both the Laureate and Phantom FM schematics do not show a tweeter cutout switch and cable. I'm wondering if the actual Laureate tuner chassis' have provision for cutting out the tweeter on AM?
Tom there is a revised version Laureate diagram in Riders Volume 15 that shows the receiver's Network 4 pin socket and band switch cut out switch for the tweeters. The late FM Philharmonic Combo info in Riders 14 shows the cutoff switch as well as a little stand alone circuit.
I now believe the only difference between the two outboard crossovers is the addition of the 35Z3 rectifier circuit to the later version crossover to support tweeters with field coil.
I have a Laureate owners manual with a 1 page insert for the crossover but no reference to a rectifier version crossover. However my Laureate power supply does have a 4 pin socket to power my crossover rectifier as stated earlier.
1939-41 amps (Philharmonic & Phantom with 6L6's) have a 4 pin socket to feed house 115 ac to the on/off switch (pins 2 & 4) and, if remote control equipped 24 volt AC ( using pins 1&4) for remote control motors. Maybe Scott added yet another 4 pin ac socket on the late 1941 amps for the rectifier version crossover or had a way to stack the crossover plug in top of the the usual 4 pin socket (like the 1936 outboard volume expander got power from a tube socket).
Perhaps there is are owners manuals for Philharmonic or Phantom or Laureate with a revision or insert showing the rectifier version crossover.
I agree that the two versions of the cross-over differ only in the addition of the 35Z3 to power the tweeter field coils. I also believe that the 35Z3 version is later and the field coil tweeters were included because magnets were needed for military production.
We know that the four pin socket on the AM-FM Philharmonic power amplifier was used to power the later cross-over of the four unit speaker system (example I sold years ago) but I am not sure this socket would have been used for remote control on this model. Have any examples of the AM-FM Philharmonic been found with remote control capability?
Norman - Not aware of any off hand, but had not been attracted to FM version sets because of the added complications restoring with obsolete FM circuits.
But I know to look closely in the future as opportunity arises for Philharmonics and Phantoms for tweeters or remote control.
Using my Laureate as an example, any really late Phantom or Philharmonic amps (late 1941 or early 42) with Jones plugs would not have needed the 4 pin socket because the ac for the on/off switch and optional 24 volt for remote control were likely included in the 12 pin receiver Jones plug socket. So perhaps no 4 pin socket would be ordinarily needed, unless for the late version crossover in which case a 4 pin AC socket hole could be punched.
Remember - I found a rechromed long Scott amp base with large holes sized for Jones Plugs and 6 tubes. The tube holes were configured for either a Phantom 6L6 amp or a Philharmonic amp. It had no 3rd hole for an ac socket however. I used it to build up a Philharmonic amp incorporating the ac lines in the 12 pin socket like the Laureate diagram shows.
Maybe someone on this site has a Jones plug equipped Phantom or Philharmonic.
Joe, - Is this the FM Phantom you started this thread concerning the rectifier version crossover photo?
The amp has 2 Jones plug sockets - 10 pin for speaker and 12 pin for the receiver cable?
Does your FM Phantom amp (two 6L6's) also have a 4 pin socket for the crossover power plug?
or the optional remote control feature?
Dave, I'm not sure. I bought 6 sets of Scott chasses. Laureate, Red Dial Phantom Deluxe, Logging scale Phantom Deluxe, Phantom Deluxe AM/FM, AW12 singled dial, and a Masterpiece that turned out to be a Super XII. Here is some info you requested:
Phantom Deluxe with logging scale--has 4 pin plug and a 7 pin plug
Phantom Deluxe Red Dial--has a 4 pin plug and a 7 pin plug
Phantom Deluxe AM/FM--12 pin Jones Plug but it has two cables connected to it. One could be a power or for switching. Haven't opened it up to see yet.
Amp #1--6L6s and 5U4s, 7 pin socket to tuner, 4 pin socket to tuner, modified 7 pin socket for speaker. I think it drives two 12 inch Magnavox speakers that I also bought. May go with one of the Phantom non-FM chasses.
Amp #2--6L6s and 5U4s, 7 pin socket for tuner, 7 pin socket for speaker, 4 pin socket for receiver
Amp #3--6L6s, 5U4s, and 6J5s, Black transformer, 12 pin Jones, 10 pin Jones, 4 pin power
Still trying to figure out which goes with which, but I think Amp #3 goes with the AM/FM Phantom, but I don't have a speaker that takes a 10 pin Jones plug.