Audio Amplifier Projects

This limiter contents owing to their rela-tively low rating, tweeters (high-fre-quency loud-speakers)form theweak linkin an audio sys-tem. If the volume is suddenly turned up too high, the risk of the tweeters being damaged irreparably is high. Such an im-petuous and costly mistake, can, how-ever, be avoided in two different ways. The first is to curb your desire to turn up the volume to levels that the loudspeakers cannot handle. The second is to build the power limiter pre-sented in this arti-cle…it’s much safer than controlling your-self when

Read the rest of this entry »

This preamplifier is intended for those audio enthusiasts who are interested in only the best. Its discrete design produces distortion figures that are measured in tenthousandths of a per cent (the remainder of its specification looks very good, too!). Moreover, bearing in mind that in certain areas the mains supply voltage is not as pure as it should be, the preamplifier is powered by rechargeable NiMH batteries.

Read the rest of this entry »

This accurate bass tone control with A difficult problem in the design of conventional stereo tone controls is obtaining synchronous travel of the potentiometers. Even a slight error in synchrony can cause phase and amplitude differences between the two channels. Moreover, linear potentiometers are often used in such controls, and these give rise to unequal performance by human hearing. Special potentiometers that counter these difficulties are normally hard to obtain in retail shops. A good alternative is a control based on a rotary switch and a discrete potential divider. The problem with this that for good tone control more than six steps are needed, and switches for this are also not readily available. Fortunately, electronic circuits can remove these Elektor 04/07/98 13:04:20

Read the rest of this entry »

This VU meter design considerations Most of us have over the years become familiar with the nervously moving pointers or LED bars of the VU (visual unit) meter on the front panel of a cassette tape recorder or mixing panel that indicate the level of the a.f. signal. The circuit presented in this two-part article is a variant of this meter that can for direct measurementsof digital audio signalsThe introduction of digital audio (CD, DCC, DAT, MiniDisc) in the 1980s has drasticallybe inserted directly inseries with the a.f. sig-changed the world of audio and hi-fi. Manynal line. Its specifica-analogue circuits have been replaced by black boxes like

Read the rest of this entry »

This converter is intended primarily for use with the sample rate converter published in the October 1996 issue of this magazine. The conversion of a symmetrical signal to an asymmetrical one requires no more than a small transformer. Amplification is not required since the AES/EBU signal is strong enough to generate the S/PDIF signal (500 mVpp into 75 .). However, the quality of the conversion

Read the rest of this entry »