Note
QST, Apr 1932, p. 96.
Radio News, Apr 1932, p. 879. (shown with the Comet, so some overlap)
QST, Jul 1932, p. 81. (1.5–20 MHz)
QST, Nov 1932, p. 69. ("new and improved")
Radio Craft, Dec 1932, p. 362.
QST, Jan 1933, p. 2.
Radio News, Dec 1933, p. 373. (now with AVC and xtal filter)
Lafayette catalog number 56, p. 65.
Radio News, Feb 1934, p. 487. (ad with info and chart re xtal filter)
Lafayette catalog number 59, p. 99.
Radio, Feb 1935, p. 3.
After the introduction of the AVC and crystal filters, older models are referred to as the "Standard Pro." See, for example, Radio News, Feb 1934, p. 487.
The Hammarlund Comet Pro is an improved version of the Comet receiver that was introduced in 1932. It has a number of enhancements over the original Comet, including:
* Sharper cutoff RF pentodes in the mixer and detector stages
* Balanced antenna inputs
* Electron-coupled oscillator for improved stability
* Higher-power audio output
* Second filter choke in the power supply for independent operation of the speaker
The Comet Pro was also available with an optional RF amplifier, which further improved its sensitivity and selectivity.
Here is a table that summarizes the key differences between the Comet and Comet Pro receivers:
| Feature | Comet | Comet Pro |
|---|---|---|
| RF pentodes in mixer and detector | Screen-grid tubes | Sharp-cutoff pentodes |
| Balanced antenna inputs | No | Yes |
| Oscillator type | RC coupled | Electron coupled |
| Audio output power | Lower | Higher |
| Power supply filter choke | One | Two |
| Optional RF amplifier | No | Yes |
Overall, the Comet Pro is a more refined and improved receiver than the Comet. It has better performance in all areas, and it was aimed at a more professional market.
Standard Pro, $88.00
Comet Pro with crystal filter, $105.84
References
Review, part 1. Radio News, Aug 1932, p. 90
Review, part 2. Radio News, Sep 1932, p. 159.
Review, part 3. Radio News, Oct 1932, p. 224.
Review (improved version), part 1. Radio News, Jan 1933, p. 418.
Review (improved version), part 2. Radio News, Feb 1933, p. 483.
Brief description. Radio News, Feb 1936, p. 473.
