Note
QST, Mar 1979, p. 153.
The McKay Dymek DR-33 is a well-regarded general coverage communications receiver that was manufactured in the USA from 1975 to 1987. It's known for its distinctive "home stereo" aesthetic, which was a deliberate design choice to make it more appealing for home environments rather than just a dedicated "ham shack" radio.
Here's a breakdown of its key features and characteristics:
Key Features & Specifications:
* Frequency Coverage: 50 kHz to 29.7 MHz continuous.
* Modes: AM, LSB (Lower Sideband), USB (Upper Sideband), CW (Continuous Wave), and RTTY (Radio Teletype, with external converter).
* Receiver System: Triple conversion superheterodyne.
* Tuning: Unique "decade tuning" system with individual knobs for each digit of the frequency, plus a fine-tuning knob for \pm 5 kHz adjustment. The display is a 6-digit red LED, showing frequency down to 100 Hz.
* Selectivity: Selectable bandwidths typically including 4 kHz or 8 kHz for AM, and 2.2 kHz mechanical filters for SSB. Optional filters (375 Hz for CW, 1200 Hz for RTTY) were available.
* Sensitivity: Generally good, with SSB/CW sensitivity typically around 0.5 \mu V for 0.4-20 MHz.
* Audio Quality: Often praised for its excellent audio output, especially on AM. It has a built-in 4-inch speaker and external speaker connectors.
* Other Features:
* S-Meter
* Automatic Noise Limiter (ANL)
* Fixed 5000 Hz notch filter
* IF (Intermediate Frequency) output jack
* Line out (600 ohms)
* Attenuator
* Mute line
* Headphone jack
* Power: Operates on 110-120/220-240 VAC, 50-60 Hz (switch selectable), consuming a maximum of 30 watts.
* Physical: Dimensions are approximately 17.5" (445mm) wide x 5.1" (130mm) high x 15" (381mm) deep, weighing around 16 lbs (7.3 kg).
* Components: Utilizes a significant number of integrated circuits (56), FETs (31), transistors (20), and diodes (66).
Performance and Reputation:
The DR-33 is generally well-regarded for its robust signal handling and excellent audio. While its "decade tuning" system might take some getting used to for those accustomed to a single main tuning knob, it offers precise frequency selection. It was popular among radio broadcast engineers and was often used as an "off-air monitor" in radio stations due to its audio fidelity and reliability.
Some users note that it might lack certain "tweeker knobs" found on more modern receivers, such as continuously variable notch filters or adjustable AGC timing, but its fixed settings are generally considered to be well-executed for most modes.
Value:
As a discontinued model, the McKay Dymek DR-33 is considered "very scarce." Used prices for the DR-33C-6 (a common variant) have historically ranged from around $480-$600, although actual prices can vary significantly based on condition, included accessories, and market demand.
In summary, the McKay Dymek DR-33 is a classic and distinctive shortwave receiver known for its solid performance, particularly its audio quality, and its unique design that made it suitable for integrating into a home entertainment setup.
The McKay Dymek DR-33 and the DR-33C are essentially the same core receiver model, with the "C" likely indicating a later revision or a specific configuration that became the standard. The DR-33C is the most commonly referenced and detailed version.
Based on available information, the key features and improvements that are often attributed to the DR-33 (and by extension, the DR-33C as its primary manifestation) over earlier models like the DR-22, are what define the "33" series. These include:
* Noise Limiter (ANL): The DR-33C specifically highlights an "original noise limiter which effectively combats interference from power lines and automobiles on both AM and SSB-CW reception." This was a significant improvement.
* Improved Frequency Readout: The DR-33C features a 6-digit LED display with 100 Hz resolution, allowing for more precise tuning.
* Refined Circuitry: While both were triple-conversion designs, the DR-33/33C generally featured a higher component count (more ICs, FETs, etc.), suggesting internal refinements for better performance.
* Class D AM Envelope Detection: The DR-33C specifically mentions the use of Class D AM envelope detection for "much lower distortion levels than the conventional AM diode detector," contributing to its praised audio quality.
It's common for electronics manufacturers to release minor revisions of a product, sometimes denoted by a letter suffix like "C," without a drastic change in model number. These revisions often incorporate small design improvements, component updates, or perhaps a standardization of features that were optional on earlier un-suffixed versions. In the case of the McKay Dymek receivers, the DR-33C appears to be the definitive and widely recognized version of the DR-33 line.
References
Review: Popular Electronics, Oct 1979, p. 82.