ETI-5000-pre-电气原理图手册

Series 5000stereo control preamplifier22t1.gned as the 'perfect partner'to our Series 5000OSFET stereo amplifier,this preamp offers manyumue features.David TilbrookNING the Series 5000 Stereo-48 to +9 dB,so a dynamic range ofthis feature is provided by the modePeamplifier we have had to57 dB can be displayed.The LED levelswitch which offers both pre-and post-at the facilities and optionsmeter displays both the peak and themonitor mono switching.If the sourceexisting preamplifiers.Theaverage of the audio signal at anymono is selected (L+R,source)the twoevolved was to design ainstant,with the peak indicator havingchannels are shorted together before thewith the accent on versa-a rapid-attack/slow-decay characteris-source-tape switch,actually at thectrol.We judged that mosttic that ensures any transient can beoutputs of the line amplifiers.This0components will be built byeasily seen on the display.The proto-monos the tape and line outputs,and theested in high quality sound,type has been tested with single pulsesinputs to the LED level meters.In thisrefore spend a considerableand even with pulses as short as 50 usway the record levels on the tape deckseitherfromsourcethe transient was accurately recordedcan be easily matched using the sourcedubbing from one deck tand easily spotted.signal itself,which is virtually im-preamp should thereforeA 400 Hz sinewave oscillator is alsopossible when the two channels have acilities for taping and tapeprovided and is selected by one of thestereo signal.positions of the tape input selector.ThisSince the L+R (source)positionenables calibration of 0 dB on the LEDmonos the channels before the balancelevel meters to match the 0 dB readingcontrol it can also be used to optimiseputs have been provided,on the tape deck meters.the left and right channel balance for awch can be selected as aThis LED level meter will also becertain listening position.Once again,or used through a con-valuable in many other projects wherethis is almost impossible to do properlye monitor circuit.Dubbingaccurate monitoring of an audio signalwhen the channels have differentck to another is simply ais required.For this reason we havesignals.ecting the playback deck asgiven it a separate project numberThe post-monitor mono facility (L+R,selecting the record deck(ETI-458).Full details were given in themonitor)shorts the channels togethermonitor facility.Now if aJune issue,so many constructors mayafter the balance and monitor levelput into record mode andalready have built the LED level metercontrols.In this way the stereo contentas a source,its outputThe preamplifier is provided withis kept valid through the balanceected via the preamplifierboth master and monitor volumecontrol so that it can be used to selectrecord input.This formscontrols.The master control varies theeither the right or the left channel andloop that would lead tooutput to the LED level meters and tofeed it simultaneously to both loud--robably within the audiothe line and tape out