Here is a Zenith console that I have, it is my favorite console. I think I picked it up in late 2017. When I got it, all you could hear was hum, and one side was dead, but I really liked the design. It was I believe the last year Zenith used tubes in their high end units - this one is a hybrid with a tube tuner and a separate chassis for the amp. All of the transistors were germanium when I got it. Right away I decided to replace the expensive output transistors with silicon outputs. There were a few (OK maybe 10 or so) resistors I had to change to make the output stage work, but now it runs cool and I believe it made a difference in the high end response. I really didn't have to do anything to the tuner except for replacing the paper and electrolytic caps. The amplifier stages in the tuner chassis were also germanium and over the past couple of years I kept chasing intermittent noise and hiss issues, so I decided to replace those as well with silicon. That was a little trickier to adjust the bias, so I ended up adding a regulated supply to stabilize the driver stage. I think the amplifier has "real" rating of somewhere between 20 and 25 watts per channel, even though Zenith says it's 320 watts of "Peak Music Power". There are no original transistors in it, they have all been replaced with silicon.
The changer was a mess and would stall with the slightest drag, but it had the in-house Zenith built 2G changer which is what I wanted. That changer was a challenge to take apart and clean up, but it works great. I like the idea of the belt driven platter. The motor spindle is a turret style that runs an idler wheel, which in turns drives the platter from a pulley on the top of that idler. The platter is about 3 pounds and is cast aluminum that rests on rubber grommets in the support suspension which was driven by the belt. It soundd much more complicated that it is, and the changer is quite good.
The woofers were the original, but they weren't very good, I did replace them with ones with butyl rubber surrounds (I didn't want to have to replace the foam later). I hear low frequencies I never would hear with the original ones. At the same time I enclosed the speaker boxes (this was a great console to do this).
Hear is a picture of the front of the console.
- Zenith MM2670 front.jpg (92.66 KiB) Viewed 2119 times
Here is a picture of the inside with Zenith's changer. The changer did get a couple of design changes in the subsequent years, but the mechanicals stayed the same. When I listen to my media player for hours (connected to the tape input) the top of the radio chassis does get warm, The console uses a minimum of 100 watts between both chassis at low volume and it will jump up to almost 200 watts a higher volume. I have a 1.5 amp slow blo fuse to protect it, (it originally had a 3 amp fuse), and I have never blown it yet.
- Zenith inside.jpg (81.83 KiB) Viewed 2119 times
Here's the back of the console showing one side of the speaker section. The way the console was built, it was very easy to add cleats and a back panel to seal it up. I also added some fiberglass inside, but didn't pack it tight. I can play pipe organ music and actually feel it in my listening chair. Even at low listening levels there isn't a lack of "bottom end". This is the console I have spent the most time on between chasing intermittent issues and hiss, but I don't think I could ever get rid of it. I smile all the time when I listen to it.
- Zenith speaker back.jpg (72.46 KiB) Viewed 2119 times
The only thing I am not totally happy with is the sound from the changer. It's clear, but lacks bass. There is a button on the tuner called "Ext Bass", but I can't leave it on using any other input as it makes the sound very boomy. I am contemplating on adding a magnetic cartridge and a preamp for the phono, but really don't want to alter the mechanics. The cartridge is very pricey to purchase another one to test (if it's available at all), and I don't use the phono all that much.
Now you have my Zenith story.
) has RCA transistors with a 274 code, with a Zenith 121-number.
