TheRed1
Console Conservationist
After reading the thread about Stephen J's 100-T which, at some point, turned into a thread on Fisher's MPX adapters, I thought now might be a good time to start a dedicated Fisher MPX thread.
Fisher's first MPX adapter, the MPX-10 came out in 1959 (perhaps as a 1960 model). It was designed to work with the Crosby multiplex system; then used by a handful of broadcasters who were experimenting with it at that time. It is the model Fisher recommended for use with both the 1960 Custom Electra III and the 1960 Premiere in their owner's manuals. It is a 5-tube model comprising 4-12AX7s and 1-12AU7.
The MPX-20 came out in 1960 specifically for concealed installations. Also intended for the Crosby system reception, it was designed to fit right into the chassis of the FM-100, 100-T and 202-T. It's curious that the 101-R tuner isn't mentioned. It is a 4-tube model using 12AX7s.
The MPX-100 was being advertised as early as May 1961 (only a month after the FCC decision) alongside such models as the TA-800, 500-S, FM-200 and the FM-50. It is a "Universal" MPX unit designed to work with any high quality, high fidelity FM receiver or tuner. The 1962 President used it conjunction with a 202-R tuner. I know I have seen an image of that control panel somewhere but I can't seem to find it. It is very impressive. The MPX-100 is a 5-tube unit consisting of 1-12AT7, 1-6AB4, 1-6AU6, 1-ECH84 and 1-12AX7.
The MPX-200 was a 4-tube version of the MPX-100 designed for concealed installations. Despite having one less tube, it has the same specs as the 100. I don't have a firm date for its release but it was out in time for the 1962 model year.
Fisher put out a pamphlet on FM Stereo Multiplex for the 1962 model year (copyright 1961) which goes into some detail on the subject. The following are some pertinent sections:
In 1963 there were three different, new MPX units: MPX-60, MPX-65 and MPX-77. All were 3-tube units with the MPX-60 consisting of 2-12AT7s and 1-12AX7. Both the MPX-65 and -77 use 3-12AX7s. I only know of MPX-60 units from the high-end consoles like the President VIII, Regent and Executive VIII - though perhaps they were also used on the very high-end tuners like the R-200 (Perhaps you could check when you get a chance, Jon). The MPX-65 is quite common, occurring in the ubiquitous 400, 500-C and 800-C receivers as well as in all of the mid-line 1963 console tuners. The MPX-77 was used in the low-end console units like the Diplomat and the Philharmonic III.
The MPX-65 and MPX-77 carried over into 1964. I'm not sure about the MPX-60. Further research is required.
In 1965 the new 2-tube MPX-125 was being used in the mid-line consoles. The MPX-77 continued on the low-end models. I'm not sure if there was a premium MPX used in on the high-end consoles. Again, further research required.
And I realize now that I didn't look at 1966 but I suspect that solid state MPX units would have made their appearance by this time. I doubt whether they had individual model numbers and were most likely an integrated part of the chassis. The MPX-77 or MPX-125 may have survived on the still-tube Philharmonic and the MPX-65 was certainly still available on the 400, 500-C and 800-C at this time.
Did Fisher ever produce a separate, solid-state MPX unit? I rather doubt it.
Further information, corrections, clarifications or questions welcome.
Fisher's first MPX adapter, the MPX-10 came out in 1959 (perhaps as a 1960 model). It was designed to work with the Crosby multiplex system; then used by a handful of broadcasters who were experimenting with it at that time. It is the model Fisher recommended for use with both the 1960 Custom Electra III and the 1960 Premiere in their owner's manuals. It is a 5-tube model comprising 4-12AX7s and 1-12AU7.
The MPX-20 came out in 1960 specifically for concealed installations. Also intended for the Crosby system reception, it was designed to fit right into the chassis of the FM-100, 100-T and 202-T. It's curious that the 101-R tuner isn't mentioned. It is a 4-tube model using 12AX7s.
The MPX-100 was being advertised as early as May 1961 (only a month after the FCC decision) alongside such models as the TA-800, 500-S, FM-200 and the FM-50. It is a "Universal" MPX unit designed to work with any high quality, high fidelity FM receiver or tuner. The 1962 President used it conjunction with a 202-R tuner. I know I have seen an image of that control panel somewhere but I can't seem to find it. It is very impressive. The MPX-100 is a 5-tube unit consisting of 1-12AT7, 1-6AB4, 1-6AU6, 1-ECH84 and 1-12AX7.
The MPX-200 was a 4-tube version of the MPX-100 designed for concealed installations. Despite having one less tube, it has the same specs as the 100. I don't have a firm date for its release but it was out in time for the 1962 model year.
Fisher put out a pamphlet on FM Stereo Multiplex for the 1962 model year (copyright 1961) which goes into some detail on the subject. The following are some pertinent sections:
If your stereophonic high fidelity system does not include an FM tuner, the best method of adding multiplex would be to purchase an FM-Stereo-Multiplex tuner, with the multiplex circuits fully integrated in the tuner design. This method is less costly than purchasing a separate tuner and adapter, and is more compact. There are three new integrated FM-Stereo-Mulitplex tuners in the Fisher group of high quality high fidelity components. These are the FM-50-B, FM-100-B and FM-200-B. Each unit combines complete multiplex facilities with the highly praised characteristics of its pre-multiplex version (Models FM-50, FM-100 and FM-200). The FM-100-B and FM-200-B include the Fisher STEREO BEACON and Automatic Switching System, while the FM-50-B has another new Fisher development - STEREO BEAM. This remarkable circuit performs in the same manner as STEREO BEACON, it signals the presence of a multiplex program. In this design, however, it is the FM Tuning Indicator that shows the presence of a multiplex program.
Those who do not own a stereophonic high fidelity installation and want to enjoy the pleasures of FM-Stereo-Multiplex can make a completely new start. The most convenient and least costly plan is to purchase an FM-Stereo-Multiplex Receiver - with everything you need on one, easy-to-install chassis. Such receivers include FM (or FM-AM) tuners, multiplex circuits, Preamplifiers, Audio Control Centers and Stereo Power Amplifiers. Simply add two speaker systems and a turntable for a complete high fidelity stereo system. If this type of stereophonic high fidelity system appeals to you, the Fisher 500-B FM-Multiplex Receiver, or the 800-B FM-AM Multiplex Receiver, will meet your most exacting requirements.
Fully anticipating the advent of FM-Stereo-Multiplex, Fisher engineers have included facilities for multiplex conversion in all Fisher stereophonic radio-phonographs. Owners of the Fisher Philharmonic II (P-25), Custom Electra V (E-46), Futura III (F-50), and Ambassador IV (A-60) can easily convert to multiplex by adding the Fisher MPX-70 adaptor. The Executive VII (Model 990) and President VII (Model 7000) are already equipped to receive multiplex stereophonically. All other models can be converted for stereophonic reception of FM-Stereo-Multiplex by the addition of the MPX-100 Universal, the MPX-200, and for some, the MPX-50. Inquire from your Fisher dealer which model to get.
In 1963 there were three different, new MPX units: MPX-60, MPX-65 and MPX-77. All were 3-tube units with the MPX-60 consisting of 2-12AT7s and 1-12AX7. Both the MPX-65 and -77 use 3-12AX7s. I only know of MPX-60 units from the high-end consoles like the President VIII, Regent and Executive VIII - though perhaps they were also used on the very high-end tuners like the R-200 (Perhaps you could check when you get a chance, Jon). The MPX-65 is quite common, occurring in the ubiquitous 400, 500-C and 800-C receivers as well as in all of the mid-line 1963 console tuners. The MPX-77 was used in the low-end console units like the Diplomat and the Philharmonic III.
The MPX-65 and MPX-77 carried over into 1964. I'm not sure about the MPX-60. Further research is required.
In 1965 the new 2-tube MPX-125 was being used in the mid-line consoles. The MPX-77 continued on the low-end models. I'm not sure if there was a premium MPX used in on the high-end consoles. Again, further research required.
And I realize now that I didn't look at 1966 but I suspect that solid state MPX units would have made their appearance by this time. I doubt whether they had individual model numbers and were most likely an integrated part of the chassis. The MPX-77 or MPX-125 may have survived on the still-tube Philharmonic and the MPX-65 was certainly still available on the 400, 500-C and 800-C at this time.
Did Fisher ever produce a separate, solid-state MPX unit? I rather doubt it.
Further information, corrections, clarifications or questions welcome.
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