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POWER CONSUMPTION

11

AUDIO INPUT

Active balanced XLR and 1/4"JACK

Balanced: 50K Ohm

Unbalanced: 25K Ohm

alanced and

nbalanced:

B

U

+21 dBu

+21 dBu

AUDIO OUTPUT

XLR and 1/4" JACK

Balanced: 60Ohm

Unbalanced: 30Ohm

20Hz to 20KHz at +0,-0.5dB

0.01% typ.1KHz ,@+4dBu

0.04% typ,1KHz ,@+20dBu

0.01% typ

>-90dBu

<-100dB

Smart knee control Compressor

Variable: from -40dB to +20dB

Variable: from 1:1 to

:1

Variable: from -20 to +20dB

Smart Gain Control Peak Limiter

Variable: from 0dB to OFF

:1

Internal reference level: from +4dBu to -10dBV

Bypass switch

Enables the ` Smart Knee Control `characteristics

Switches input and output for the level meter

Linking CH1 (master) and Ch2, CH3 (master) and CH4; stereo operation

6. TECHNICAL SPECIFICATIONS

+4dBu /-10dBV

>55dB @1KHz

COMPRESSOR SECTION

PEAK LIMITER SECTION

FUNCTION SWITCHES

INDICATORS

POWER SUPPLY

DIMENSIONS

WEIGHT

Type

Impedance

Maximum input level

Type

Impedance

Maximum output level

Bandwidth

THD +N%

IMD

Noise

Crosstalk

Type

Threshold

Ratio

Output

Type

Threshold

Ratio

OPERATING LEVEL

BYPASS

SMART

I/O METER

COUPLE

Operating Level

CMRR

GAIN REDUCTION: 8 element LED

INPUT / OUTPUT LEVEL: 8 element LED

PEAK LIMITER THRESHOLD: 1 element LED (Limiter Function )

Function switch: LED indicator for each

483 (W) 194.5 (D) 44 (H)mm (19" 7.7" 1.7")

3.1kg (6.83lb)

14 Watts

95-120V

/210-240V

, 60-50Hz FUSE: 210-240V: T315mAL 250VAC

95-120V: 630mAL 250VAC

Summary of Contents for ACL4

Page 1: ...QUAD COMPRESSOR LIMITER ACL4 User s Manual LTO R www altoproaudio com Version 1 1 September 2005 English ...

Page 2: ...uct away from naked flames Read these instructions Follow all instructions Keep these instructions Do not discard Heed all warnings Only use attachments accessories specified by the manufacturer Do not tamper with the power cord or plug These are designed for your safety Do not remove Ground connections If the plug does not fit your AC outlet seek advice from a qualified electrician Protect the po...

Page 3: ...dreams with you paying attention to your suggestions and your comments Following this idea we create our products and we will create the new ones From our side we guarantee you and we will guarantee you also in future the best quality the best fruits of our continuous researches and the best prices Our LTO ACL4 is the result of many hours of listening and tests involving common people area experts...

Page 4: ...IND 4 2 2 Voltage Controlled Amplifier VCA 2 3 Inputs 3 CONTROL ELEMENTS 6 4 7 READY TO ROLL 4 1 Compressor Section 4 2 Peak Limiter Section 6 TECHNICAL SPECIFICATIONS 11 7 WARRANTY 12 3 5 INSTALLATION AND CONNECTION 9 5 1 Mains Connection 5 2 Audio Connection 5 3 Rack Mounting ...

Page 5: ... to manufacture audio equipment with a very high dynamic range up to 125 dB But the dynamic range of digital equipment is more or less 25 dB A further reduction in dynamic range occurs with the use of tape recorders and or vinyl records 2 1 1 It is not just Music Yes a piece of electronic will produce some noise When the current flows through a conductor this will generate a certain movement of th...

Page 6: ...ters more or less do the same job but Limiters brutally limit the audio signal above a set threshold while Compressors handle signal in a much more civilised way and over a wide range of levels If an audio signal exceed the threshold set by the User the limiter will kill any audio signal above that threshold Period Also Compressors perform their function when the audio signal exceed a certain thre...

Page 7: ...oose 10dBV or 4dBu Consequently the Meter will be the Input or Output Level with a range from 24dB to 18dB 8 Meter for Gain Reduction The gain reduction will be shown by this Meter with a range of 1 to 30dB Pic 1 R LTO POWER OFF ON ACL4 QUAD COMPRESSOR LIMITER 30 25 20 15 10 6 3 GAIN REDUCTION dB 1 INPUT OUTPUT LEVEL dB 24 18 12 6 0 6 12 18 LIM dBu 10 30 20 10 40 THRESHOLD 10 1 2 N 1 RATIO 2 5 0 2...

Page 8: ...READY TO ROLL 4 1 Compressor Section Sophisticated Voltage Controlled Amplifiers VCA are responsible of the control of dynamics in the ACL4 The operating range of our VCA is more than 60dB This mean that the input level or the output level can be increased or decreased in a range of 60dB Signals below the set threshold will not be reduced so the dynamic control will be activated as soon as the sig...

Page 9: ...ould use a Ratio of 4 1 or lower With the SKC circuit Smart Knee Control you can avoid aggressive compression generated by using high ratios How we achieve this Introducing a soft knee curve in the range of up to 10dB above the threshold level Hard Knee compression is then used beyond this range Output Hard Knee Threshold Gain 0 dB Ratio 2 1 Ratio 4 1 Limiter 1 SKA Curve Input Chart 3 SKA characte...

Page 10: ...ut signal The area in between the two is the amount of gain reduction The unit will activate the limiter when the signal exceeds the threshold for more than 20 microseconds Then 1 second after that the signal is below threshold again reduction goes back to 0dB and in this case input and output signals are again identical Chart 5 SGC characteristic of the limiter section 5 INSTALLATION AND CONNECTI...

Page 11: ...ssor Limiter on high temperature devices such as power amplifiers etc to avoid overheating Pic 4 Pic 5 For XLR connector XLR Type Unbalanced XLR Type alanced B Pin3 Pin2 Pin1 Linked to Pin1 manually Pin1 Pin2 Pin3 Tip Ring Sleeve Tip Ring Sleeve Tip Sleeve Tip Sleeve Tip Sleeve Cent e r Cent e r Centre Screen Screen Screen 1 2 3 Tip Ring Sleeve 1 2 3 1 2 3 TIP SLEEVE TIP SLEEVE TIP RING SLEEVE TIP...

Page 12: ...tches input and output for the level meter Linking CH1 master and Ch2 CH3 master and CH4 stereo operation 6 TECHNICAL SPECIFICATIONS 4dBu 10dBV 55dB 1KHz COMPRESSOR SECTION PEAK LIMITER SECTION FUNCTION SWITCHES INDICATORS POWER SUPPLY DIMENSIONS WEIGHT Type Impedance Maximum input level Type Impedance Maximum output level Bandwidth THD N IMD Noise Crosstalk Type Threshold Ratio Output Type Thresh...

Page 13: ...d of LTO 1 year from the purchase date if you have completed the Warranty Registration Card in time 3 2 The warranty service is only available to the original consumer who purchased this product directly from the retail dealer and it can not be transferred 3 3 During the warranty service may repair or replace this product at its own option at no charge to you for LTO parts or for labor in accordan...

Page 14: ...13737 email alto altoproaudio com Fax 886 4 22346757 c All rights reserved to ALTO All features and content might be changed without prior notice Any photocopy translation or reproduction of part of this manual without written permission is forbidden Copyright 2005 SEIKAKU GROUP SEIKAKU TECHNICAL GROUP LIMITED ...

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