Audiophile Quiz
November 1957 Radio-Electronics

November 1957 Radio-Electronics [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Electronics, published 1930-1988. All copyrights hereby acknowledged.

I could be wrong, but I'm guessing the average audiophile in the 1950s and 1960s were probably more technically astute than modern day audiophiles in terms of electrical and physical specifications. That is largely due to how integrated, matched, and compatible system components (receivers, players, amplifiers, speakers, etc.) are nowadays. Newer audio components are also more tolerant of non-optimal configurations. In 1957 when this Audiophile Quiz appeared in Radio−Electronics magazine, the vast majority of electronics equipment used vacuum tubes that used lethally high voltages, so connection and servicing mistakes could be more costly to life, limb, and hardware. Topics like AFC (automatic frequency control), frequency response of recording and playback devices, required technical knowledge for achieving the best performance. See answers at the bottom of the page.

Audiophile Quiz

By Herman Burstein

1. If a power amplifier rated at 100 watts produces 12.5 watts for an input of 0.5 volt, it will produce 25 watts for an input of 1 volt.

2. It is more important for phonograph turntable to rotate at a steady speed than at an accurate speed.

3. Single-cone speakers are often superior to coaxial and two-way systems in the same price class.

4. Many AM broadcast stations meet high-fidelity requirements so far as frequency range is concerned.

5. Since afc (automatic frequency control) increases distortion, it is best to operate an FM tuner with afc off, if this is optional.

6. The principal difference between professional and home tape recorders operating at 7:5 ips is in their high-frequency response.

7. If a high-fidelity system contains a loudness control, then a gain control is superfluous.

8. Sometimes 300-ohm TV ribbon (antenna lead-in) is used to connect a power amplifier to a speaker, often because it is flat and therefore convenient for running beneath a rug. However, since the impedance of the power amplifier and of the speaker is usually in the range of 4 to 16 ohms, it is not advisable to use 300-ohm wire for this purpose.

9. To minimize record wear, the tracking force of a phonograph stylus should be as light as possible consistent with its faithfully following the undulations of the groove. If one does err, it is better to err in the direction of slightly too little rather than slightly too much tracking force.

Quizzes from vintage electronics magazines such as Popular Electronics, Electronics-World, QST, and Radio News were published over the years - some really simple and others not so simple. Robert P. Balin created most of the quizzes for Popular Electronics. This is a listing of all I have posted thus far.

Audiophile Quiz Answers

  1) False - It will produce 50 watts, because power varies with the square of the voltage.

  2) True because most human ears can tolerate deviations from correct speed - for example, 34 instead of 33 1/2 revolutions per minute - of as much as 1%, 2% or even 3% without these deviations being perceptible or annoying. However, extremely small departures from steady rotation (wow and flutter) - well below 0.5% - are perceptible and annoying to most persons.

  3) True - Mere division of the audio spectrum between two or more speakers is not sufficient for reproduction that is smooth, low in distortion and adequate in range. There are several single-cone speakers on the market which in these respects outperform multiple speaker systems at comparable total price. On the other hand, the ultimate in audio today is obtained by multiple-speaker systems that use specially designed units for each portion of the audio spectrum.

  4) True - AM stations are not required to cut off above 5,000 cycles, as is often supposed. Many maintain flat response to 12,000 or even 15,000 cycles. However, most AM tuners cut off sharply above 5,000 cycles or thereabouts for design reasons and to minimize inter-station whistle. Some high-fidelity AM tuners do maintain response well above 5,000 cycles, but unless the signal is a relatively strong one, noise and adjacent-channel interference may become unpleasant.

  5) False because, if anything, afc decreases distortion. The disadvantages of afc are a slight loss in sensitivity - in most cases much too small to be of importance - and difficulty in separating a weak station from a nearby strong one; that is, with afc on, the tuner tends to capture the strong signal rather than the weak one if the two are close to each other on the dial.

  6) False. Many home recorders have high-frequency response extending as far as that of their professional brethren. The principal differences, for the same frequency response, are lower distortion and higher signal-to-noise ratio in the professional machine. Distortion includes that due to rumble and flutter in the transport mechanism.

  7) False. Maximum setting of a loudness control should correspond to the original level of the music and should provide flat response; as the control is backed down, bass should be augmented relative to the other frequencies. However, signal level will vary according to program source and other factors. Thus it is necessary by means of the gain control to restore the condition at which the maximum loudness control setting corresponds to original level.

  8) False - TV ribbon line is perfectly suitable for connecting a power amplifier to a speaker. Because of its low capacitance per foot, it may be more suitable than other kinds of wire where a long run is required - except where low-efficiency speakers and high-wattage amplifiers are used at high levels, as power loss in small-diameter ribbon line may become excessive. Ribbon line may be used as its 300-ohm impedance does not have any effect unless it is terminated in a 300-ohm load.

  9) False because too little tracking force will result in an increase in distortion because the stylus no longer completely follows the groove. Moreover, there will be greater wear than that due to slightly excessive tracking force because the stylus bounces around instead of adhering to the groove.

Posted July 14, 2022