Somewhere toward the back of Magnavox's 1963 catalog are tube models being offered with a longer warranty.
This was a clever way to move the last ones out with an incentive that addresses the preference for new Astro-sonics having "no tubes to burn out"
With no exceptions, all the tube Magnavox consoles I saw used either push-pull 6L6, 6V6 or 6BQ5. Never a single-ended amp did I see. Over the last year, I have encountered these Magnavox consoles I always knew existed but never saw one until two were in the shop a year ago.
The Amplifiers come in two versions; AMP196 and AMP86 as do the tuner chassis; 79-XX and 59-XX. The next post will highlight the differences between them, problems I encountered and creative solutions to them.
This year of production of Magnavox should make an interesting topic. I was not aware of any Magnavox stereo that used a 6L6 in 1963. And I understand that the AMP-series of amps were done after 1960.
Life can be tough. It can be even tougher if you're stupid.....
electra225 wrote: ↑Thu Dec 07, 2023 4:04 pm
This year of production of Magnavox should make an interesting topic. I was not aware of any Magnavox stereo that used a 6L6 in 1963. And I understand that the AMP-series of amps were done after 1960.
I meant to say the 6L6 tubes are only in the 40s models I have, most later amps used 6V6GT until these last ones including AMP 93 used 6BQ5
Further pictures and analysis will most certainly compare only the last of these 6BQ5 consoles as they were phased out .
Magnavox phased in solid state Astrosonic and Magnasonic electronics and phased out tube models over the 1963-64 model year. The last tube models appeared similar to earlier tubed models but designs were intended now to prolong component life. The swan song of Magnavox tube models was underway as Fisher, RCA Victor, Motorola and Zenith were still making full-power tube amps.
A "Silver Seal" warranty was offered on these last tube models as they were expected to need fewer repairs. This is akin to the automakers dropping compression ratios on the V8 engines model years 1971-72. As you felt the difference under your foot and in your seat, this difference can be clearly heard in the amplification and overall sound quality.
The AMP-175 and AMP-185 were fantastic 6V6 pp stereo amps through 1962, a very similar AMP-88 used 6EU7 instead of 12AX7 and reduced power supply voltages, reducing power output and requiring more preamplification from few tubes just like the portable tube models.
The early series 59-01 to 08 tuner/controls used in 1962 models have provision to add FM mpx and tape input. There is one preamp tube 12AX7 right after tone controls, the output is a higher level going to the AMP-196, allowing gain to be balanced between two stages to reduce hum and other noise.
the models that had a tuning meter used similar chassis 79-10, which I mentioned in the first post.
Looking at the later series after tuner/preamp chassis 79-10 was phased out, series 59-10 to 14 tuners used just ONE preamp tube on the amp. The 12AX7 has been eliminated with a hole plug instead. These tuner/controls have no provision to add mpx either. I have just done one like it with just a three-position AM-FM-Stereo selector, not even a TAPE input!
Even the speakers were changed to 12" "square magnet" woofers the cheaper SS models used. Manufacturers changed from CTS 137 to Mag 232, a downgrade in this case.
In conclusion, the last of Mag's tubed models were kind of lame. The biggest issue is the reduction to one preamp stage. This required a higher-output ceramic cartridge, more gain needed to drive the 6BQ5s resulting in very compromised fidelity like a portable player. The best thing about it was the Micromatic record changer that all models used.
To the best of my knowledge, the Magnavox "AMP-XXX" designation for their amps and components ended with the 1960 model instruments. Starting with the 1961 models and continuing thru the last tube models in 1963, Magnavox used the "XX-XX-XX" six digit designation. "88-02-00", "93-02-10". "57-03-00", you get the idea. My 1963 model 2ST653 stereo has the 88-series amp with 6V6 P-P output. The connections for the various components, phono, tape, MPX are all on the top of the chassis, like was done on the Astro-Sonic amp chassis, rather than on the rear apron of the chassis like on the earlier models. Also, this chassis has a unique Molex connector so you can't use the previous 70-series Multiplex Adapters. You have to use a proprietary model like was used in component systems. There is an AC plug provided on the chassis to plug a MPX in. Magnavox started using Japanese-built tubes in their amps and in some tuners starting in 1961. Siemens is alleged to be the manufacturer. My 1961 Symphony with the 93-series amp had RCA-sourced 6BQ5 output tubes and a Sylvania-sourced 5U4 rectifier. My 1961 Concerto has the 88-series amp with Japanese-sourced 6V6 P-P output. The 1962 Stereo Theater I have had all Radio Shack tubes in it when I got it, except the 5U4 rectifier. That was Sylvania-sourced. I don't know who built the original output tubes, but I always figured they were also Japanese. The 6CA4 rectifier in the Concerto is Sylvania-built. All the tubes that I have had out of the 1963 Contemporary 2ST653 have been made in Japan. All the tubes except one of the 6EU7's are original in this little stereo. I will respectfully disagree with your statement about chintzy performance in the '63 tube models. Ours is my wife's daily driver. A very high hour set. It has a 12" and a 4' and a 5" speaker in each channel. Bass is adequate. Like all the 88-series amps I have or have had experience with, you have to run the treble control fully advanced for the audio to be sufficiently bright. The '63 Magnavox tube tuners had AFC, a massive improvement in selectivity and to prevent drifting, the bane of earlier Magnavox tube tuners. Mine still uses the S-600 version of the Collaro changer with the 9" platter. This one has an EV 132 cartridge. It still has the traditional hardwood cabinet with "ten coats of hand-rubbed oil finish". The 2ST653 is the lowest-priced stereo I have in my Magnavox collection. And, like I have mentioned before, my personal opinion is that the smaller Magnavox stereos are the equal, if not better, performers of their bi-amped relatives. To the best of my knowledge, only the 88- and 93-series P-P amps were offered in 1963. The bi-amped Imperial and Concert Grand models are not listed in the '63 catalog. I have never seen a documented example of either of these instruments for 1963.
The way Magnavox tossed their tube models under the bus, while introducing the Astro-Sonic models has to go down in history as one of the more bizarre marketing schemes there ever was. But, in fairness to Magnavox, they never built a hybrid chassis in their stereos. You either got all tubes, or all transistors. RCA, Zenith and most of the other players in this business, made hybrid chassis. They either couldn't get their scald right on the solid state models, or they couldn't decide which direction they wanted to go. RCA brought out their New Vista series of Victrola stereos in 1963 to take advantage of their new Dynagroove recordings. I'm not up on the history of Zenith and the others, but 1963 was a pivotal year for recording techniques and for the reproduction instruments. I know GE and maybe Admiral still made all-tube models later than 1963. I have a Motorola stereo with a hybrid chassis from 1965.
Life can be tough. It can be even tougher if you're stupid.....
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