Mitsubishi Electric LT-3280 Service Manual page 29

2 . 2 . 2 . 2 . 2 . Audio circuits Audio circuits Audio circuits Audio circuits Audio circuits
It explains the audio circuits and speaker system of LT-3780,LT-3280.
Our design spec is as follows.
Power outputs : Total 10W(5W*2(L,R))
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Impedance : 8+/-1.2 ohms
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Compact sound 2 way bass reflex speaker box.
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(Refer to an attached "Audio block diagram of LT-3780, LT-3280", regarding as the flow of audio signal.)
2-1. Audio process circuits
(M)IC301 : Audio processor IC (MSP3440G : Micronas)
This models are used the MSP3440G as the audio processor.
This IC's functions are as follows.
- Volume control
- Tone control
- Surround
- L/R mixing
- Audio line output
This model has some sound effect features on user menu, Bass, Treble, Balance, Surround, Level
Sound.
Audio adjustment of those in this model is performed by this IC.
2-2. Audio amplifiers circuits
(N)IC370, IC380 : Single Ended Audio Amplifier IC (MP7720DS-Z : MPS)
This model apply digital Audio Amplifier in order to decrease power consumption.
This amplifier voltage is 14V and SAMPVCC(for Sub Woofer)).
2-5. Speakers
No. ITEM
1 Nominal
2 Lowest Resonance 180 +/- 36Hz
3 Effective / Rated
Frequency Range
4 Rated Input
5 Maximum Input
MODELS: LT-3280D/LT-3780D
SPECIFICATION
8 ohms +/- 1.2%
F0~20KHz
OUT PUT SPL-10dB
10W
15W
Page 29