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It only takes a minute to sign up. I have a preamp rescued from an old stereo: BA I have looked for meanings of ALC online, and I have found 2 possible meanings that would fit this device:. What is it? How should I connect it? It's a major feature of this chip, and I guess it's assumed you know what it is as you chose the chip. Notice how the amplifier is used for amplifying for both recording and playback.
The same tape head is also used for both functions. ALC automatic level control was an important function in tape recorders, as the signal had to be the right level, strong enough to overcome noise but not too high to cause saturation. A variable-gain amplifier is a bit tricky to do without distortion, so having it integrated into the preamplifier was a convenience for the system designer.
I don't know what you plan to do with the part, but an obvious choice would be an audio compressor. It won't be super high-fidelity, but maybe good enough for a guitar stomp box. If they talk all the time about ALC, and fail to explain what it is, all I can say then is that the datasheet stinks.
The application example on page 3 gives us some idea. The ALC signal is taken from the output, via a diode and an external capacitor. That means it's a peak detector, whose level is then used to control the amplifier's amplification. So that looks very much like Automatic Level Control, though Audio Limiter Control is a close relative, if not exactly the same.
There's a block diagram that looks like the ALC picks up the output signal and uses it to adjust integrated potentiometers at the input pins of the forward path. It looks like the IC is intended to be used with cassette tape recorders. Cheapo recorders often don't have a potentiometer where one can set the recording level. Instead, an circuit tries to adjust the level of the signal that is to be recorded such that it is neither too silent and vanishes in the tape noise, nor too loud so it would cause tape saturation distortion.
The text next to Fig. Basically, there's an RC combination that allows you to set how fast the IC will react to varying levels of the signal. Sign up to join this community. The best answers are voted up and rise to the top.
Home Questions Tags Users Unanswered. What is ALC on a preamp? Ask Question. Asked 8 years, 8 months ago. Active 7 years, 11 months ago. Viewed 5k times. Majenko Majenko Active Oldest Votes. Fancy posting a link to it? That's the one I linked to - it has no circuit in it. Don't you just hate it when they do that? Tuvshin Tuvshin 1. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.
The preamplifiers have high gain and low distortion, and can be directly coupled to the tape head without coupling capacitors. This prevents tape head magnetization and "pop" noise generation. A built-in rectifier means that an ALC circuit with good channel balance and large dynamic range can be constructed with addition of just an external time constant circuit. The ICs also include power-on mute circuits that suppress "pop" noise generation.
BA3308 DATASHEET PDF
ICs with built — in ALC circuits for use in stereo amplification. The preamplifiers have high gain and low. PDF datovy list. Dual preamplifier with.
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By continuing to use the forum you conform your acceptance of these. If you are not happy to accept these you must stop using the forum and delete our cookies from your browser. User Name Remember Me? Getting a BA Auto level chip to work! Hi, I have not used one of these before, but the data sheet looked quite sensible so I ordered one and have been having a play with it.
BA3308 - DUAL PREAMPLIFIER WITH ALC