The Fine Things are Always Hand Made
Been a variety of threads here mentioning tweeters. And now on ARF, a growing thread on AW-23 tweeters.
Thought a separate tweeter thread here on the Scott site might be useful for newer Scott owners.
- Scott first offered optional tweeters in 1935 with the introduction of the early 5 knob AW-23 on account of a few new experimental wide band high fidelity AM radio stations at the top of the broadcast band - in a handful of major cities like Chicago. The 12 inch Magnavox 38 ohm pedestal speaker had provision for a pair of field coil tweeters via a 5 pin socket on the speaker pedestal. The tweeters were wired in series with a "Y" cable and a 2 MFD cap to limit low frequencies and favoring higher frequencies to the Q4 series tweeters #7077A and #7078A .
- Effective January 1936, Scott revised the speaker(s) in conjunction with other changes for the introduction of the 7 knob AW-23 model produced well into late 1937. The revised Magnavox 12 inch pedestal has a gray color cone, a 19 ohm voice coil and revised terminal board behind the little cover. The revised optional field coil tweeters are Q4 series tweeters #8685A and #8686A. Same field coils but different voice coils.
- The PHILHARMONIC introduced Spring 1937, offered an optional tweeter pair with permanent magnets, no field coils. Initially they look just like the silver painted AW-23 tweeters and were also wired in series on a "Y" cable with a 2 MFD cap but had a 2 pin plug for the 2 pin socket on the 15 inch 38 ohm speaker pedestal base.
- There may have been an appearance change to bullet shaped tweeter covers before 1940. Until 1940, no other Scott model was offered tweeters but the AW-23 and Philharmonic.
- Late 1939, the AM/SW PHANTOM amplifier was redesigned (Scott News: Vol 11 number 5) thusly: 1) to use a pair of 6L6's (instead of 6V6's), 2) the 6J5 drivers were relocated next to the two 6L6's, 3) 5U4s (replace the 5V4's) for a B+ circuit revised for the same B+ voltage as the Philharmonic and 4 ) a single 15 inch flange mount 38 ohm speaker with field coil with tap like the Philharmonic's. But no provision for tweeters.
-About March 1940 (Scott News Vol 12 number 2, page ) Scott announced the new optional 4 unit high fidelity speaker system. The same issue announced the first FM Scotts - an FM Phantom and the seldom found FM only tuner to add FM reception to any AM/SW Scott model using the phono input. The FM Philharmonic came a few months later in mid 1940. The standard Phantom and standard Philharmonic continued as well.
-The new optional 4 unit high fidelity speaker system had an outboard crossover with the output transformer to drive all speakers, each with 8 ohm voice coils. (Documented in Riders Vol 14 under Scott.) The tweeters each had a 2 pin plug, no longer in series on a "Y" cable. The crossover was more sophisticated with large caps and top mounted inductors. Also had a jumper plug to be repurposed for an auxiliary/remote speaker if desired. Only the main speaker had a field coil which was fed B+ via the crossover. The crossover had a small 4 pin cable to the receiver for the band switch to limit tweeter operation to the FM band only. Appears the Phantom and Philharmonic used the the same 4 unit high fidelity system, although the Phantom received a 12 inch speaker flange mount while the Philharmonic, a 15 inch. Both the 12 and 15 inch main speakers were 8 ohm and had a "High Fidelity" sticker and no output transformer attched.
-to add confusion - I recently acquired an FM Phantom that had been housed in a phono combo credenza cabinet and optional 4 unit speaker system. The main speaker was 15 inch, not 12. The crossover also has the 35Z5 rectifier and the two tweeters had field coils and 4 pin plugs. The radio used Jones plugs for both set and speaker cables. Evidently late production, possibly even early 1942 when materials were getting redirected for the war and Scott was assembling his last civilian radios.
-The 1941 FM/AM/SW Scott Laureate was offered a 12 inch standard speaker or the optional high fidelity speaker system, same crossover as my FM Phantom but with only one tweeter which was center mounted in a 15 inch speaker, thus a co-axial. Laureates were always fitted with Jones plugs for the set and speaker cables. My example has a same crossover with the same 35Z3 rectifier to power the field coil of the single tweeter (4 pin plug), and 2nd tweeter socked is unused. Same cable to receiver for band switch to control when the tweeter was active.
-I suspect there are some late Philharmonic examples equipped with Jones Plugs and maybe with the optional speaker system using field coil tweeters. Speak up if you have one.
- The post war 800B coax speaker was much like the prewar Laureate coaxial but the crossover function was not by outboard crossover. The 800B tweeter is switched off on AM and SW bands.
Additional info postings invited to this tweeter thread.