Tuesday, December 1, 2009

Restoration Complete! Zenith Model K725, Chassis 7K01

I am very excited because I just completed the restoration of my
Zenith model K725 (chassis 7K01). This radio has a build date of
February 22, 1954. It is capable of both the standard AM broadcast
band and the modern FM band (88-108 MHz).

The build quality is very good. The internals were very clean and
easy to service. It was very straight foreword to find things from
the schematic inside of the radio. I'm sure this radio was designed
to be serviced.

The audio quality of this radio is absolutely amazing! I think this
is largely due to the fact that its audio power amplifier is a single-
ended class A power amp with negative feedback. There is a tone
control knob that is located on top of the tuning indicator that
adjusts the frequency response of the feedback network for this audio
power amplifier. All of this results in a nice warm sound on the FM
bands. The local jazz program sounds amazing, especially when soft
jazz guitar or a mellow Hammond B3 organ song is played.

I will write up a web article on my site about this with more details
to follow soon.