Alto EQU231TWIN-MKII V2 User manual

www.altoproaudio.com
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Version 1.0
MODEL: EQU231TWIN- MKII V2
Revised on Jan,2010

CONTENTS
1. Introduction..................................................................................................................1
2. Specification.................................................................................................................2
3. Block Diagram..............................................................................................................3
4. Schematic Diagram.....................................................................................................4
5. Wiring Diagram............................................................................................................8
6. PCB Layout.................................................................................................................9
7. Test Procedure...........................................................................................................12
8. Exploded View & Mechanical Parts List.....................................................................16
9. BOM List....................................................................................................................18

The EQU231TWIN-MKII V2 Graphic Stereo 31-Band Equalizer is an extremely musical and
flexible Graphic Equalizer, based on many years of experience and designed to provide a
permanent precise equalization to musician, performer, and studio engineer. It can be used
wherever is requested to modify the frequency “contour” of a sound and can offer a solution
to many common sound problems and allows the user to use the creativity to obtain nice
results in terms of sound characterization.
The EQU231TWIN-MKII V2 Graphic Stereo 31-Band Equalizer Features:
Constant Q circuitry with a 3% center frequency accuracy
Control range +/-6dB/+/-12dB selectable
Active balanced and unbalanced input and output connectors
Variable input level control
Signal clop pilot
Ground “LIFT” switch to disconnect signal ground from chassis ground
Power off automatic bypass function
Line voltage selectable robust and compact design
Manufactured under QS9000, VDA6.1 certified management system
1. Introduction
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Type EQU231TWIN-MKII V2 2*31-Band: 1/3 Octave, ISO spacing(3H series)
Slider Travel 45mm with positive centre detent
Range +/-6dB or +/-12dB selectable
Active balanced XLR and 1/4'' TRS
Unbalanced RCA
20k Ω(bal.)
15k Ω(unbal.)
Maximum input level 14 dBu
Active balanced XLR and 1/4'' TRS
Unbalanced RCA
Output impedance ＜600Ω
High pass filter 40Hz(12dB/Oct)fixed-button type
Low pass filter 16KHz(12db/Oct)fixed-button type
Frequency response 20 Hz to 50kHz at -1.5dBu
THD+N% ＜0.01% (@1kHz, all VR at middle position)
S/N Ratio 110dB
95V -120V AC -60Hz
220V-240VAC -50Hz/60Hz
Consumption 18W
Dimension 483(W)*220(D)*132(H)mm (19''*8.66''*5.1'')
Power supply
Input impedance
Output connections
Input connections
2. Specification
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3. Block DIagram
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4. Schematic Diagram
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5. Wiring Diagram
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6. PCB Layout
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EQU231TWIN-MKII V2 Finished Product Test
Test Instruments
1. AP (Audio Precision)
2. Dual-track oscilloscope
Instrument setting
1. Set proper AC input voltage
2. Connect the output signal of AP to the input of EQU231TWIN-MKII V2
3. Connect the output of EQU231TWIN-MKII V2 to the input of AP
Adjustment according to following procedures
1. Set the potentiometer of 31-band EQ in center, set the input level at 0dB, all buttons out
2. Turn input level to maximum, the output level shall be +12dB+/-1dB, and the distortion shall be
0.009%+/-0.001%
3. Set INPUT LEVEL at minimum, the output level shall be -12dB+/-1dB, and distortion shall be
0.01%+/-0.02%
7. Test Procedure
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4. Adjust the input level so that the AP output is 0dB, the frequency response is as following
10Hz~22kHz +/-2dBu
5. Adjust the input level so that the AP output is 0dB, press the HI-pass button and the frequency
response is as following
6. Adjust the input level so that the AP output is 0dB, press the low pass button and the frequency
response is as following
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7. Press EQ button down, keep RANGE out and the LED indicates +12, adjust slide buttons to
maximum and minimum, measure the frequency response independently and the curve shall
be as following
8. Turn off the AP input signal and set input level as maximum, the AP setting is as following, now
it shall be no more than -82dB
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9. Turn on the AP input signal, and set the input level at maximum, theAP setting is as following,
the maximum non-distortion level is +28dBu+/-1dB and distortion is 1%
10. Now, the S/N shall be no less than 110dB
11. Connect AP input and output to Channel 2,repeat steps 1~10
12. All slides shall be set in center and all buttons out before shipping
~Test Completed~
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MODEL No: EQU231TWIN-MKII V2
8. Exploded View & Mechanical Parts 
List
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S/N Part No Description Specification Qty
1 MB03290 chassis EQU231TWIN-MKⅡ1
2 MB03287 rear panel EQU231TWIN-MKⅡ_V1.0 1
3 MC00578 top cover EQU231MKⅡ1
4 MA04866 front panel EQU231TWIN-MKⅡALTO_V1.1 1
5 MI02057 AC socket EQU231TWIN-MKⅡ_V1.0 1
6 TC00212 fixed voltage transformer PT-231-II-230V 1
7 TC00212 fixed voltage transformer PT-231-II-230V 1
8 MG00042 black screw M3*10 2
9 NI00315 PWR SW button 5*5*9(3.3*3.3) 8
10 MG00061 black screw M3*10 12
11 HK00327 K-PCB P-131VU 2
12 HI00026 PWR SW RA12KKATOF 2P 1
13 MG00025 black screw M3*6 20
14 MG00041 black screw M3*6 22
15 ME00016 multicolored nut 4mm 1
16 MF00038 spring washer φ4*φ7*1t 3
17 MF00048 outer gear washer φ4*φ8*0.5t 3
18 NI00002 plastic nut Hexφ7/16"*G20/15*4.8 4
19 MI01998 Fixed bracket EQU231MKII 1
20 HK04127 K-PCB P-EQU231TWIN FP-II-DIP 2
21 HK04110 K-PCB P-EQU231TWIN SW-II-DIP 2
22 HK02063 K-PCB P-EQU31EQ-II-DIP 2
23 HK002065 K-PCB P-EQU31PU-II-DIP 2
24 HK02066 K-PCB P-EQU31PU-II-1-DIP 1
25 MG00182 Nickel screw M2*2.5 24
26 NC00131 Wood washer φ1*φ11.3*15.3 red 4
27 MJ00808T FixedPWR plate WL3-32 6
28 MG00251 copper post M3*17.5*0.5PH 3
29 MG00241 copper post M3*30*0.5PH 6
30 MG00245 copper post M3*15*0.5PH 3
31 MG00250 copper post M3*22*0.5PH 3
32 NI00501 Adhesive cushion 12.7*9*3t
(
SF-004
)
4
33 MG00408 copper post M3*33*0.5PH 3
Mechanical Parts List
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Class Part No Description Specification Insert location Remark
PF03072 EQUALIZER EQU231TWIN-MKⅡV2_ALTO_127V_CHINA
├0001 TC00266 transformer-RS PT-231-MKⅡ_127V
├0002 NI00501 self-adhere foot cushion 12.7*9*3t(SF-004)
├0003 NI00252 sleeve φ4*20mm
├0004 NI00240 sleeve φ2.5*10mm
├0005 NI00315 power switch button-cambered surface 5*5*9(inner 3.3*3.3) 1.function key
├0006 NI00218 cable tie ALT-102SB
├0007 NF01783 instruction English EQU MKⅡSERIES ALTO_V1.2
├0008 NI00002 plastic nut-RS φ7/16"*G20/15*4.8
├0009 NE12788 label EQU231TWIN-MKⅡ_V1.0
├0010 NF00061 assurance card-RS-C ALTO_V1.1
├0011 NE05004 label ALTO PF_V1.2
├0012 NE02717 label MADE IN CHINA
├0013 NB02908 inner case-RS-CT EQU231TWIN-MKⅡV2 ALTO_V1.1
├0014 NB02906 barrier EQUTWIN-MKⅡ(3H)_V1.0
├0015 ND00347 dustproof cloth 0.35t*348.5*128mm black 2016B_V1.0
├0016 NB03163 carton EQU213TWIN-MKⅡALTO_V1.0
├0017 NA00279 clip-chain bag 0.04t*100*150mm_V1.0
├0018 NA00862 PE bag-RS 0.04t*580*300 mm
├0019 NA00137 clip-chain bag 5*7
├0020 MG00025 screw-RS M3*6
1.fix topcover*10.rear
panel*3,front panel*9,
bracket*4,front
board*6
├0021 MG00041 screw M3*6 1fix PCB
├0022 MG00042 screw M3*10 1.fix AC socket
├0023 MG00061 screw-RS M3*10 1fix MIC jack
├0024 MG00182 screw M2*2.5
├0025 MF00038 washer-RS φ4*φ7*1t 1.fix GND
├0026 MF00048 washer-RS φ4*φ8*0.5t 1.fix GND
├0027 ME00016 color nut 4m/m 1.fix GND
├0028 MG00262 screw M4*8
├0029 MC00578 top cover EQU231MKⅡ
├0030 MG00241 copper pillar M3*30*0.5PH
├0031 MG00251 copper pillar M3*17.5*0.5PHsingle,length23.5
├0032 MG00245 copper pillar M3*15*0.5PH
├0033 HI00026 power switch-RS RA12KKATOF 2P 1.PWR SW
├0034 HD00023 glass tube fuse 200mA 250V φ5.2*20mm CSA/S/UL/VDE
├0035 HA00841 power cord(America 3P) LT-202+18A*3C(SVT) 6FT+LT-501
├0036 HA03856 wire-RS 5P-5P 350mm UL1007 28AWG 1.CN1 to FP board
CN5
├0037 HA03403 wire 6P-6P 250mm UL1007 26AWG
├0038 HA01835 wire-RS 70mm brown L10R10
├0039 HA02195 wire-RS 3P-3P 120mm UL1015 18AWG
├0040 HA01333 signle terminal wiring CF:W76 150mm UL1015 18AWG green/yellow 1.AC socket GND
├0041 AD00012 twin adhesive-RS 90*120mm_V1.0
├0042 MG00635 copper pillar φ5*M3*0.5PH*14.6
├0043 HK04110 PC board-RS P-EQU231TWINSW-Ⅱ-SMD
│ ├0001 HB01235 PCB EQU231TWINSW-Ⅱ(2*2)_VER040830
│ ├0002 RA00967 fixed resistor 1/8W 10KΩR1,R2,R3,R4,R5,R6,R7,R8,R9
│ ├0003 HA01920 wire-RS 6mm J9
│ ├0004 HA01922 jump 8mm J2,J7,J11
│ ├0005 HA01925 jump 10mm J1,J3,J4,J5,J10
│ ├0006 HA01931 jump 16mm J8
│ ├0007 HA01937 jump 18mm J12
│ ├0008 HA01932 jump 20mm J6
│ ├0009 HI00162 push-button switch 2 paragraphs 6p PS-22E8552L SW1,SW2,SW3
│ ├0010 HI00163 push-button switch 2 stage 12P PS-42E85 SW4
│ ├0011 SA00053 L.E.D φ3 round(red)long foot 26mm LED4,LED7,LED9
│ ├0012 SA00052 L.E.D φ3 round(green)long foot 26 LED3,LED6,LED8
│ ├0013 SA00054 L.E.D 3m/m round(yellow)long foot 26 LED1,LED2,LED5
│ ├0014 NI02049 LED spacer support LEDS-14 14mm
│ ├0015 HA03155 wire-RS 18P-3P/5P*2/6P 140/350/400/350mm UL1007 CN1
│ └0016 AC00603 lead free soldering bar S100
9. BOM List
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