Magnavox AC-2 Amplifier, 1921
Archived listing from the original vintage-amplifier.com. Prices, seller details and purchase links have been removed; this page is a reference record, and nothing here is for sale. About this archive.
Here’s a magnificent 1921 Magnavox AC-2 amplifier. The amp is original, it’s working, it’s in excellent condition (still has its original Magnavox hang tag and cabinet label), and it comes a good pair of early, tipped amber glass UV-201 tubes. The tubes have been tested in the amplifier, and they still work. The AC-2 was designed to be used with either radio or PA input, with B+ plate voltages running as high as 90v. It can be used with almost any 1920’s battery radio or crystal set and can be powered by either dry cell batteries or a regulated DC power supply (such as an ARBEIII).
As you can see in the photos, the condition of this amplifier is excellent throughout. The panel is beautiful and undamaged, with legible engraved lettering and original nickel plating on the control assembly that still gleams. Cabinet is likewise in excellent condition, with an original finish that’s still as smooth as satin and an original full-color Magnavox decal that’s almost perfect. Chassis is clean and correct and original, and the huge original Magnavox AF transformer is still good. The 1st stage rheostat is open on a single turn at the very beginning of its travel, but this has no effect on the functionality of the amp, as the rheostat is in the off position when the stator is at that setting anyhow. Both rheostats gradually raise and lower the voltage, as they should, and both amplifier stages work properly, as you toggle each one off and then on. A few of the binding post nuts have worn threads, but they can still tighten down on battery wires.
The Magnavox license on the underside of the base is original and the original hang tag is in excellent condition. If you want to operate the amp, you’ll need a regulated DC power supply or high current, low voltage dry cells for the tube filaments (1 amp) and high voltage, low current batteries for the tube plates. Please note: this is not an AC amplifier. You do don’t simply plug it into a wall outlet. Also, it must be impedance matched to both input and output devices, and it was designed to be used with early 1920’s radio and public address devices, not 1950’s audio gear. Depending on what type of input device you’re using, and how that device is grounded, a separate, dedicated DC power supply may be required for the amp.
About this model
The oldest amplifier in the archive by decades. The AC-2 is a 1921 two-stage audio amplifier for battery radios and crystal sets, with two UV-201 tubes, one per stage, and a large Magnavox audio transformer. It runs on batteries or a regulated DC supply: about one amp at low voltage for the filaments and up to 90 volts for the plates. The seller was emphatic that it is not an AC amplifier despite the name, and cannot be plugged into the wall.
The UV-201 was one of RCA's early receiving tubes, and the "tipped amber glass" the seller mentions is typical of early examples. Magnavox at the time was a young company; it had been formed in 1917 from the business of Edwin Pridham and Peter Jensen, co-inventors of the moving-coil loudspeaker.
| Maker | Magnavox, USA |
|---|---|
| Model | AC-2 |
| Year | 1921 (listing) |
| Type | Two-stage audio amplifier for battery radio and PA |
| Tubes | 2 × UV-201 (listing) |
| Power | Batteries or regulated DC; plates up to 90 V (listing) |
Questions collectors ask
Can the Magnavox AC-2 be plugged into the mains?
No. Despite its name it runs on batteries or a regulated DC supply, as the archived listing stresses.
What tubes does the Magnavox AC-2 use?
Two UV-201 triodes, one for each amplifier stage.
Sources: Wikipedia: Magnavox.
