Tapco Stereo Amplifier T 231 User Manual

20  
25 31.5 40  
50  
63  
80 100 125 160 200 250 315 400 500 630 800  
1k 1.25k 1.6k 2k 2.5k 3.15k 4k  
5k 6.3k 8k  
10k 12.5k 16k 20k  
LEVEL  
+17  
+12  
-
-
HI PASS LOW PASS  
BYPASS  
RANGE  
0
0
1
1
-12  
-
DUAL 31 BAND GRAPHIC EQUALIZER  
40Hz  
16kHz  
CLIP  
6dB 12dB  
RANGE  
T•231  
BY  
-
-
HI PASS LOW PASS  
BYPASS  
ON  
+12  
+17  
0
OFF  
2
2
POWER  
-12  
40Hz  
16kHz  
CLIP  
6dB 12dB  
20  
25 31.5 40  
50  
63  
80 100 125 160 200 250 315 400 500 630 800  
1k 1.25k 1.6k 2k 2.5k 3.15k 4k  
5k 6.3k 8k  
10k 12.5k 16k 20k  
LEVEL  
SERIAL /DATE CODE  
CHANNEL  
OUT  
IN  
1
2
OUT  
IN  
RISK OF FIRE  
REPLACE FUSE AS MARKED  
WARNING  
NO OUTDOOR USE  
OUT  
OUT  
IN  
BROUGHT TO YOU BY THE GROOVY FO  
MANUFACTURED IN CHINA  
"TAPCO" AND "MACKIE" ARE REGISTERE  
LKS IN WOODINVILLE, WA, USA  
FABRIQU  
D
E
AU CHINE  
TRADEMARKS OF  
COPYRIGHT  
UNBAL  
BAL/UNBAL  
BAL  
BAL  
LOUD TECHNOLOGIES INC.  
©2003  
OUT  
IN  
CHANNEL  
OUT  
IN  
WWW.TAPCOGEAR.COM  
IN  
RISK OF ELECTRIC SHOCK  
DO NOT OPEN  
WARNING: TO REDUCETHE RISK OF FIRE OR ELECTRIC SHOCK,  
DO NOT EXPOSETHIS EQUIPMENTTO RAIN OR MOISTURE. DO NOT REMOVE COVER.  
NO USER SERVICEABLE PARTS INSIDE.REFER SERVICINGTO QUALIFIED PERSONNEL.  
AC 100-120V, 60Hz  
AC 200-240V, 50HZ  
RATED INPUT: 12.5W  
T
AVIS: RISQUE DE CHOC ELECTRIQUE  
NE PAS OUVRIR  
LIFT  
GND  
UNBAL  
BAL/UNBAL  
BAL  
BAL  
315mA 250V  
by  
 
18. Exposure to extremely high noise levels may cause permanent  
hearing loss. Individuals vary considerably in susceptibility to  
noise-induced hearing loss, but nearly everyone will lose some  
hearing if exposed to sufciently intense noise for a period of  
time. The U.S. Governments Occupational Safety and Health  
Administration (OSHA) has specied the permissible noise  
level exposures shown in the following chart.  
According to OSHA, any exposure in excess of these permissible limits  
could result in some hearing loss. To ensure against potentially dangerous  
exposure to high sound pressure levels, it is recommended that all persons  
exposed to equipment capable of producing high sound pressure levels  
use hearing protectors while the equipment is in operation. Ear plugs or  
protectors in the ear canals or over the ears must be worn when operating  
the equipment in order to prevent permanent hearing loss if exposure is in  
excess of the limits set forth here.  
Duration Per Day Sound Level dBA,  
Typical  
Example  
In Hours  
Slow Response  
8
90  
Packed garage concert  
6
92  
4
95  
VW Bus Peace Train  
3
97  
2
100  
102  
105  
110  
115  
Cranked psychedelic tunes  
High speed chase on C.H.I.P.s  
Loudest parts at a Heavy Metal concert  
1.5  
1
0.5  
0.25 or less  
What me, read a manual?  
Before you begin, please make sure you read the Safety Instructions on page 2 and  
Getting Started on page 4.  
Your new TAPCO® T231 is designed to set up quickly and operate easily. We know its  
often seen as a sign of weakness to read a manual, along with asking for directions when  
lost, but maybe you can read the rest when nobody is looking.  
It is important to keep your receipt in a safe place, and not a bad idea to write your  
product information here for future reference (i.e., insurance claims, tech support, return  
authorization, etc.).  
Product Serial #:  
Purchased at:  
Date of purchase:  
Part No. 0009427 Rev. A 1/04  
©2004 LOUD Technologies Inc. All Rights Reserved.  
3
 
Getting Started  
The following steps will help you set up your T231, and get the  
levels just right.  
SETTINGS:  
1. Be sure the T231s POWER switch is off.  
SET THE CONTROLS:  
1. Make sure your signal source is turned up and  
delivering signal to the T231. The signal should  
pass through the T231 unaffected because the  
CHAN 1 and 2 BYPASS buttons are out and the  
signal processing circuitry is bypassed.  
2. Set all the sliders to their center positions and all the  
switches out.  
CONNECTIONS:  
2. Push in the CHAN 1 and 2 BYPASS buttons to  
1. Using balanced or unbalanced cables, connect  
your mixers main outputs to the T231s inputs,  
and the T231s outputs to your amplifers (or  
powered speakers) inputs.  
enable the graphic equalizer circuits.  
3. You can turn up and down each individual slider  
and hear how it affects the sound.  
If you are using the T231 in a channels insert,  
connect your mixers channel inserts to your  
T231s INPUTs and OUTPUTs.  
4. You can turn up and down the input LEVEL controls  
to make it louder or softer. When the LEVEL control  
is at the center detent, it is at unity gain (it doesnt  
boost or cut the signal).  
Note: The T231 31-Band Graphic  
Equalizer is designed to be inserted  
LOOK  
Things To Remember:  
in-linewith the signal as a  
serial device. This means that the  
When you shut down your  
equipment, turn off the ampliers  
rst. When powering up, turn on the  
ampliers last.  
entire signal is routed through the  
CLOSER  
processor, in contrast to a parallel  
device where the processed signal is mixed back  
with the unprocessed signal, like a reverb or echo.  
Save the shipping box and  
packing material! You may need it  
someday.  
2. Connect the cables using either XLR or 1/4”  
TRS connectors (balanced), or 1/4TS or RCA  
connectors (unbalanced).  
The XLR, TRS, and RCA inputs for each channel  
are wired in parallel. Use only one input per channel.  
The XLR, TRS, and RCA outputs for each channel  
are wired in parallel.  
The balanced XLR connectors are wired as  
follows:  
Pin 1 = shield (ground)  
Pin 2 = hot (+)  
Pin 3 = cold ()  
The 1/4TRS connectors are wired as follows:  
Tip = hot (+)  
Ring = cold ()  
Sleeve = shield (ground)  
3. Plug all the sound system components into suitable  
AC outlets, properly grounded and capable of  
delivering adequate current.  
4. Turn all the equipment on. If you are monitoring the  
signal through speakers, turn the power amplier  
on last to avoid getting any pops or thumps  
through your speakers.  
4
 
Contents  
Safety Instructions................................................................2  
Getting Started....................................................................4  
Introduction..........................................................................6  
Hookup Diagrams................................................................8  
Typical Hookup: In-line with Main Outputs.....................8  
Alternate Hookup: Individual Channel or Main Inserts ..8  
T231 Features ....................................................................9  
FRONT PANEL FEATURES .................................................9  
1. EQ Sliders ...............................................................9  
2. Input LEVEL ............................................................9  
3. HI-PASS ..................................................................9  
4. LOW-PASS ..............................................................9  
5. BYPASS....................................................................9  
6. CLIP ........................................................................9  
7. RANGE ...................................................................9  
8. POWER ...................................................................9  
REAR PANEL FEATURES..................................................10  
9. Line Cord Socket and Fuse................................10  
10. AC Select Switch ..............................................10  
11. GND LIFT Switch ................................................10  
12. OUTPUTS .............................................................10  
13. INPUTS.................................................................10  
GENERAL PRECAUTIONS AND CONSIDERATIONS .....11  
Rack Mounting........................................................11  
Thermal Considerations .........................................11  
AC Power Considerations......................................11  
Appendix A: Service Information ....................................12  
Warranty Service..........................................................12  
Troubleshooting............................................................12  
Repair ............................................................................13  
Appendix B: Connections ................................................14  
Appendix C: Technical Info..............................................15  
T231 Specications ....................................................15  
T231 Block Diagram ...................................................16  
Frequency Chart..........................................................18  
TAPCO LIMITED WARRANTY...............................................19  
for more information about this and other TAPCO products.  
5
 
Introduction  
®
Thank you for choosing a TAPCO Tweeq31-band graphic  
®
equalizer by Mackie . The TAPCO product line hails back to the  
days of TAPCO Corporation, Greg Mackies rst company. TAPCO  
revolutionized the audio industry back in 1969 with the very rst 6-  
channel mixer specically designed for keyboards and rock Nroll PA.  
In essence, TAPCO redened the price performance ratio and  
made high-quality professional audio mixers accessible to virtually  
anyone. Today, TAPCO is reborn with the same ideals and is backed  
by the world-class engineering and manufacturing horsepower of  
Mackie. The TAPCO T231 is the rst graphic equalizer in the TAPCO by  
Mackie® family.  
TAPCO version of Greg  
About Graphic Equalizers  
The tone controls on your home stereo system typically have a bass and treble control,  
and sometimes a midrange control, that you use to boost or cut a broad band of  
frequencies. When you leave the controls in the center position, they do nothing.  
A graphic equalizer works in much the same way, except that it has many more controls  
that operate over much narrower frequency bands. The T231 has 31 controls that boost or  
cut different frequencies, each centered on ISO standard frequencies ranging from 20 Hz  
to 20 kHz and affecting 1/3 of an octave.  
Constant Q Design  
The T231 is designed with constant Q lters. The Q of a lter refers to its quality. A lter  
with a low Q affects a broader band of frequencies than a lter with a high Q (Q=f /BW, for  
c
you technoids!). Constant Q means that, as a slider is boosted or cut, the bandwidth of the  
lter (the skirtof the affected frequencies) remains the same. Lower quality proportional  
Q lters have a broader bandwidth as the lter is boosted or cut, which can extend out to  
an octave or more.  
Whazzit Used For?  
There are a number of uses for graphic equalizers in a sound system. They can be used  
to correct the frequency response of a loudspeaker, or to adjust for resonant peaks and  
dips in a room. Sometimes they are used to simply bring out the characteristics of a voice or  
instrument to improve the intelligibility and articulation of the sound.  
In any case, please remember that a graphic equalizer is a tool that can be used to  
improve the overall sound, but it cannot make up for frequency response deciencies  
caused by poor system design or poor acoustics. Try and get the best possible sound  
from the system before attempting to use equalization by paying attention to proper gain  
structure and loudspeaker placement. Often times just moving a loudspeaker to a different  
position can have a dramatic effect on the overall sound in the room.  
Probably the most common use of a graphic equalizer is placing it in-line between the  
mixing boards main outputs and the power amplier inputs (see hookup diagram on page 8)  
When used with a real-time analyzer and pink noise generator, it can be used to ne tune  
the acoustic frequency response and get it as at as possible in a room.  
.
TAPCO van (a.k.a. micro bus)  
6
 
However, often times a perfectly at frequency response is not what you want in a live  
sound application. For example, if the low-frequency response of the loudspeakers only  
extends to 50 Hz, there is no need to amplify the frequencies in the lowest octave of the  
audio frequency range, 20 Hz to 40 Hz. You can use the T231 to roll off these frequencies,  
which reduces the drain on the amplier and provides more power to amplify the higher,  
more useful frequencies.  
You might want to boost the higher frequencies a bit to add brightness and sizzle to the  
sound. If the sound system is for the speaking voice, boosting the mid frequencies around  
2-4 kHz can improve the intelligibility of the voice. Boosting 125 Hz, 250 Hz, and 16 kHz can  
improve a vocal. Try as you might to eliminate it, there may still be a residual 60-cycle hum  
in the speakers. You can use the 63 Hz slider to notch down the hum (the 125 Hz slider can  
help eliminate residual buzz).  
A graphic equalizer can be used to reduce feedback. If you dont have a real-time  
analyzer to identify the peaks that cause the feedback, you can do a fairly good job by  
ear using the following procedure.  
1. Set all the sliders on the T231 to the center position (zero).  
2. Slowly turn up the master volume on the mixer until feedback just begins to occur.  
You can usually hear a soft ringing sound that gradually increases in volume. BUT BE  
CAREFUL! Feedback can occur quickly and become very LOUD, very fast.  
3. Cut the appropriate slider, corresponding to the feedback frequency, until feedback  
stops. It may take some practice to identify the frequency where the feedback is  
occurring, but your accuracy will improve the more familiar you become with it.  
4. Repeat until you cant isolate a specic frequency in the feedback.  
This procedure helps to minimize the resonant peaks in the room. Its a little more difcult  
to identify and adjust for dips in the room response. This is best done from experience  
listening for gaps in the sound of particular instruments or voices. Once youve identied  
them, boost the slider for that particular frequency range by 3 to 6 dB to help smooth the  
frequency response.  
Another application for a graphic equalizer is patching it into a channel insert to  
enhance the sound or change the tonal characteristics of a vocal or instrument (see  
hookup diagram). The Sound Frequency chart on page 18 is a good reference to locate  
the frequency ranges of particular voices and instrument.  
The Tweeq Seriesof processors are powerful and tough. They are designed to  
withstand the punishing rigors of the road and continue to perform day after day, year  
after year.  
Heres a quick glance at the features packed into the T231:  
2-channel 31-band graphic equalizer with constant Q circuitry and great sound quality  
Switchable 6 and 12 dB control range for wide or ne tweaking  
High-pass lter @ 40 Hz to remove unwanted low frequencies  
Low-pass lter @ 16 kHz to remove unwanted high frequencies  
Bypass switch allows quick A/B comparisons  
Independent signal clip indicators on each channel  
Input gain control for EQ signal compensation  
Balanced 1/4" TRS and XLR, and unbalanced RCA input and output jacks  
Selectable line voltage  
7
 
Hookup Diagrams  
Typical Hookup:  
In-line with Main Outputs  
FROM MIXING  
CONSOLE LEFT AND  
RIGHT MAIN OUTPUTS  
SERIAL/DATE CODE  
CHANNEL 1  
OUT  
IN  
OUT  
IN  
RISK OF FIRE  
REPLACE FUSE AS MARKED  
WARNING  
NO OUTDOOR USE  
OUT  
OUT  
IN  
BROUGHT TO YOU BY THE GROOVY FOLKS IN WOODINV  
ILLE, WA, USA  
MANUFACTURED IN CHINA  
FABRIQUE AU CHINE  
"TAPCO" AND "MACKIE" ARE REGISTERED TRADEMARK  
UNBAL  
BAL/UNBAL  
BAL  
BAL  
S
OF  
LOUD TECHNOLOGIES INC.  
COPYRIGHT ©2003  
OUT  
IN  
CHANNEL 2  
OUT  
IN  
WWW.TAPCOGEAR.COM  
RISK OF ELECTRIC SHOCK  
DO NOT OPEN  
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,  
DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. DO NOT REMOVE COVER.  
NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.  
AC 100-120V, 60Hz  
AC 200-240V, 50HZ  
RATED INPUT: 12.5W  
T
AVIS: RISQUE DE CHOC ELECTRIQUE  
NE PAS OUVRIR  
LIFT  
GND  
UNBAL  
BAL/UNBAL  
BAL  
BAL  
315mA 250V  
TO POWER AMPLIFIER OR  
POWERED SPEAKERS INPUTS  
Alternate Hookup:  
Individual Channel or Main Inserts  
RETURN  
SEND  
TO CHANNEL OR MAIN INSERT  
SERIAL/DATE CODE  
CHANNEL 1  
OUT  
IN  
RISK OF FIRE  
WARNING  
REPLACE FUSE AS MARKED  
NO OUTDOOR USE  
OUT  
IN  
O
OUT  
IN  
BROUGHT TO YOU BY THE GROOVY FOLKS IN WOODINV  
ILLE, WA, USA  
FABRIQUE AU CHINE  
"TAPCO" AND "MACKIE" ARE REGISTERED TRADEMARK  
MANUFACTURED IN CHINA  
UNBAL  
BAL/UNBAL  
BAL  
BAL  
S
OF  
LOUD TECHNOLOGIES INC.  
COPYRIGHT ©2003  
OUT  
IN  
CHANNEL 2  
OUT  
IN  
WWW.TAPCOGEAR.COM  
RISK OF ELECTRIC SHOCK  
DO NOT OPEN  
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,  
DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. DO NOT REMOVE COVER.  
NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.  
AC 100-120V, 60Hz  
AC 200-240V, 50HZ  
RATED INPUT: 12.5W  
T
AVIS: RISQUE DE CHOC ELECTRIQUE  
NE PAS OUVRIR  
LIFT  
GND  
UNBAL  
BAL/UNBAL  
BAL  
BAL  
315mA 250V  
RETURN  
SEND  
TO CHANNEL OR MAIN INSERT  
8
 
T231 Features  
2
3 4  
7
5
20  
25 31.5 40  
50  
63  
80 100 125 160 200 250 315 400 500 630 800  
1k 1.25k 1.6k 2k 2.5k 3.15k 4k  
5k 6.3k 8k  
10k 12.5k 16k 20k  
LEVEL  
+12  
+17  
-
-
HI PASS LOW PASS  
BYPASS  
RANGE  
0
1
1
-12  
-
DUAL 31 BAND GRAPHIC EQUALIZER  
40Hz  
16kHz  
CLIP  
6dB 12dB  
RANGE  
T231  
BY  
1
-
-
HI PASS LOW PASS  
BYPASS  
ON  
+12  
+17  
0
8
OFF  
2
2
POWER  
-12  
40Hz  
16kHz  
CLIP  
6dB 12dB  
20  
25 31.5 40  
50  
63  
80 100 125 160 200 250 315 400 500 630 800  
1k 1.25k 1.6k 2k 2.5k 3.15k 4k  
5k 6.3k 8k  
10k 12.5k 16k 20k  
LEVEL  
6
FRONT PANEL FEATURES  
The controls for Channels 1 and 2 are the same, so  
these descriptions apply to both channels.  
5. BYPASS  
1. EQ Sliders  
This button effectively disables the EQ circuits. You  
can use this button to compare the EQd signal to  
the unprocessed signal. When the BYPASS button is  
pushed in, the LED below the BYPASS button lights.  
When the EQ sliders are in the center position, they  
have no effect on the signal. Move a slider up or  
down to boost or cut a particular frequency by up to  
12 dB ( 6 dB when the RANGE switch is set to 6 dB).  
6. CLIP  
2. Input LEVEL  
This LED lights when the output signal is within 5 dB  
of clipping. It is okay if the CLIP LED blinks occasionally,  
but if it blinks frequently or stays lit all the time, turn  
down either the LEVEL control or the output signal  
from the mixer or other device immediately preceding  
the T231.  
Use the Input LEVEL control to adjust the gain of the  
signal as it passes through the T231. When the Input  
LEVEL control is in the center position, it provides no  
gain (unity gain). When the slider is all the way down  
the signal is off (-), and all the way up provides 17 dB  
of gain.  
7. RANGE  
3. HI-PASS  
This determines the maximum boost and cut of  
the EQ sliders, either 12 dB or 6 dB (pushed in). The  
corresponding LED below the RANGE button indicates  
the setting.  
The 12 dB setting provides more boost and cut if it  
is needed for more drastic EQ requirements. The 6 dB  
setting provides less boost and cut, but allows you to  
ne tune the controls with more precision.  
This button is used to roll-off the frequencies below  
40 Hz. The LED below the button lights to indicate  
when the HI-PASS lter is turned on.  
This is useful to reduce stage rumble (low-frequency  
noise from footsteps picked up by microphones on  
stage) and microphone-handling noise.  
If the T231 is used with monitor speakers, turning  
on this button can reduce the muddiness caused by  
the lows from the stage monitors feeding back into  
the main output through the microphones.  
8. POWER  
Use this switch to turn the T231 on and off. The LED  
4. LOW-PASS  
above the switch lights when the power is on.  
Use this button to roll-off the frequencies above  
16 kHz. The LED below the button lights to indicate  
when the LOW-PASS lter is turned on.  
This is useful to remove hiss and high-frequency  
noise from the signal.  
9
 
13  
12  
SERIAL/DATE CO
CHANNEL 1  
OUT  
IN  
OUT  
IN  
RISIRE  
REPLACE MARKED  
9
WARNING  
NO OUTDOOR USE  
OUT  
OUT  
IN  
IN  
10  
BROUGHT TO YOU BY THE GROOVY FO  
MANUFACTURED IN CHINA  
"TAPCO" AND "MACKIE" ARE REGISTERE  
LKS IN WOODINVILLE, WA, USA  
FABRI  
D
QUE AU CHINE  
TRADEMARKS OF  
COPYRIGH  
UNBAL  
BAL/UNBAL  
BAL  
BAL  
LOUD TECHNOLOGIES INC.  
T
©2003  
OUT  
IN  
CHANNEL 2  
OUT  
IN  
WWW.TAPCOGEAR.COM  
RISK OF ELECTRIC SHOCK  
DO NOT OPEN  
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,  
DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. DO NOT REMOVE COVER.  
NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.  
AC 100-120V, 60Hz  
AC 200-240V, 50HZ  
RATED INPUT: 12.5W  
T
AVIS: RISQUE DE CHOC ELECTRIQUE  
NE PAS OUVRIR  
LIFT  
GND  
UNBAL  
BAL/UNBAL  
BAL  
BAL  
315mA 250V  
11  
REAR PANEL FEATURES  
9. Line Cord Socket and Fuse  
However, occasionally a ground loop can be  
created in a system where the signal ground is  
connected to chassis ground, which can cause a  
hum or buzz to appear in the audio signal. If this is  
the case, try moving the switch to the LIFT position to  
eliminate the hum or buzz.  
Here is where you connect the detachable line  
cord that came in the box with your T231. Plug  
the other end of the line cord into an AC outlet  
properly congured with the voltage required for your  
particular model (see AC Select Switch next).  
The fuse is located behind the fuse cover, at the  
bottom of the IEC socket. See the Troubleshooting”  
section on page 12 for information about replacing  
the fuse.  
12. OUTPUTS  
Three types of connectors are provided for the  
outputs balanced male XLR and 1/4TRS (Tip-  
Ring-Sleeve), and unbalanced RCA. These balanced  
outputs are in parallel, and provide exactly the same  
signal on all three outputs, regardless of which input  
jack is used. You can connect either a balanced TRS  
connector or an unbalanced TS connector to the 1/4”  
output jack.  
10. AC Select Switch  
Set this switch to the correct voltage setting for the  
country you are in, 115 VAC or 230 VAC.  
Note: The T231 is shipped with the AC Select  
switch set to the 230 VAC position. If you are in a  
country that uses 100-120 VAC, remove the cover  
plate with a phillips-head screwdriver and set the  
switch to the 115 VAC position. A 315 mA fuse  
is used for both voltages (115V/230V). See the  
Troubleshootingsection on page 12 for instructions  
on replacing the fuse.  
13. INPUTS  
Three types of connectors are provided for the  
inputs balanced female XLR and 1/4TRS (Tip-Ring-  
Sleeve), and unbalanced RCA. These inputs are in  
parallel, so do not connect more than one signal at  
a time to the input jacks for each channel. You can  
connect either a balanced or an unbalanced signal to  
the 1/4input jack.  
11. GND LIFT Switch  
When the switch is in the GND position, the audio  
ground is electrically connected to the chassis  
safetyground. Normally, this is how the switch is set.  
See Appendix B: Connectionson page 14 for  
information on input and output connection wiring.  
10  
 
GENERAL PRECAUTIONS AND CONSIDERATIONS  
Rack Mounting  
The T231 is designed to be mounted in a standard  
rack. It requires two rack spaces (2U = 3.5). It also  
requires 7.5depth inside the rack, not counting the  
rear connectors. When designing your rack, put the  
heavier items at the bottom and the lighter items  
toward the top.  
Secure the front panel of the T231 to the front of  
the rack using four screws with soft washers to prevent  
scratching the panel.  
Thermal Considerations  
Avoid mounting the T231 directly over devices  
that produce heat, such as power ampliers. As with  
all electronic components, it is best to provide cool air  
circulation around the T231 to avoid overheating. The  
ambient temperature should not exceed 113˚ F (45˚ C).  
AC Power Considerations  
Be sure the T231 is plugged into an AC outlet that  
is able to supply the specied voltage, and the AC  
Select switch is set to the correct voltage.  
Be sure the AC outlet can supply enough current  
to allow full power operation of all the components  
plugged into it, especially if there are power ampliers  
plugged in. The outlet should be a three-prong socket  
that matches the power cord.  
WARNING: Bypassing the plugs  
safety ground pin can be  
dangerous. Dont do it!  
11  
 
Appendix A: Service Information  
No Sound  
Warranty Service  
Is the signal source turned up? Make sure the  
Details concerning Warranty Service are spelled  
out in the Warranty section on page 19.  
signal level from the mixing console (or whatever  
device immediately precedes the T231) is high  
enough to produce sound through the system.  
If you think your T231 has a problem, please do  
everything you can to conrm it before calling for  
service. Doing so might save you from the deprivation  
of your equalizer and the associated suffering.  
These may sound obvious to you, but here are  
some things you can check. Read on.  
Are you using the T231 with an insert plug in an  
insert jack? Make sure that you are using an insert  
cable, and not a mono Y-cable.  
Poor sound  
Troubleshooting  
Is it loud and distorted? Turn down the signal  
coming from the mixer or signal source.  
No Power  
Is the input connector plugged completely into  
the jack? Make sure all connections are good and  
sound.  
Our favorite question: Is it plugged in? Make sure  
the AC outlet is live (check with a tester or lamp).  
Our next favorite question: Is the POWER switch  
on? If not, try turning it on.  
Switch the BYPASS switch in and out to compare  
the sound with the equalizer in the signal path and  
out of the signal path. This can help determine if  
the problem is with the T231 or elsewhere in the  
system.  
Is the red LED above to the POWER switch  
illuminated? If not, make sure the AC outlet is live.  
If so, refer to No Soundbelow.  
Is the fuse blown? If the POWER LED on the front  
panel is not illuminated and you are certain that  
the AC outlet is live, if is possible the fuse has blown.  
Noise/Hum  
Check the signal cable between the mixer and  
the T231. Make sure all connections are good  
and sound.  
To remove and replace the fuse:  
1. Disconnect the line cord from the IEC socket.  
Make sure the signal cable is not routed near AC  
cables, power transformers, or other EMI-inducing  
devices.  
2. Remove the fuse drawer by prying it open with a  
small screwdriver. It will slide all the way out.  
Is there a light dimmer or other SCR-based device  
on the same AC circuit as the T231? Use an AC  
line lter, or plug the T231 into a different AC  
circuit.  
FUSE  
3. Remove the fuse and replace it with an  
equivalent-type fuse:  
315 milliamp slo-blo (T315 A/250 V)  
Note: The same fuse is used for both 115 VAC and  
230 VAC operation.  
4. Replace the fuse drawer by pushing it all the way  
back into the IEC socket.  
5. Reconnect the line cord and turn the POWER  
switch on.  
If two fuses blow in a row, then something is wrong.  
See the Repairsection on the next page to nd  
out what to do.  
12  
 
Repair  
Service for TAPCO products is available from one  
of our authorized domestic service centers or at our  
factory, located in sunny Woodinville, Washington.  
Service for TAPCO products living outside the United  
States can be obtained through local dealers or  
distributors.  
5. Include a legible note stating your name, shipping  
address (no P.O. boxes), daytime phone number,  
RA number, and a detailed description of the  
problem, including how we can duplicate it.  
6. Write the RA number in BIG PRINT on top of the box.  
Units sent to us without the RA number will be refused.  
If your T231 needs service, follow these instructions:  
1. Review the preceding troubleshooting suggestions.  
Please.  
7. Ship the T231 to us. We suggest insurance for all  
forms of cartage. Ship to this address:  
TAPCO  
2. Call Tech Support at 1-877-827-2669, 7 am to 5 pm  
PST, to explain the problem and request an RA  
(Return Authorization) number. Have your T231s  
serial number ready. You must have an RA number  
before you can obtain warranty service at the  
factory or an authorized service center.  
SERVICE DEPARTMENT  
16220 Wood-Red Road NE  
Woodinville, WA 98072  
3. Keep this owners manual and the detachable line  
8. Well try to x the T231 within ve business days.  
Ask Tech Support for the latest turn-around times  
when you call for your RA number. The T231  
must be packaged in its original packing box,  
and must have the RA number on the box. Once  
its repaired, well ship it back the same way in  
which it was received. This paragraph does not  
necessarily apply to non-warranty repair.  
cord. We dont need them to repair the T231.  
4. Pack the T231 in its original package, including  
endcaps and box. This is very important. When  
you call for the RA number, please let Tech  
Support know if you need new packaging. You  
can order new packaging through our parts  
department. LOUD Technologies is not responsible  
for any damage that occurs due to non-factory  
packaging.  
Lonely? Looking for that special someone? Do you have a question about  
your TAPCO product?  
Please call our Technical Support folks at 1-877-827-2669, Monday to Friday, from 7 am to 5 pm PST.  
13  
 
Appendix B: Connections  
XLR Connectors  
1/4" TS Phone Plugs and Jacks  
The inputs and outputs use 3-pin male and female  
XLR connectors. They are wired as follows, according  
to standards specied by the AES (Audio Engineering  
Society).  
TSstands for Tip-Sleeve, the two connection  
points available on a mono 1/4" phone jack or plug.  
They are used for unbalanced signals.  
SLEEVE  
SLEEVE  
TIP  
2
SHIELD  
COLD  
HOT  
TIP  
TIP  
1
3
SLEEVE  
1/4" TS Unbalanced Wiring:  
Sleeve = Shield  
Tip = Hot (+)  
SHIELD  
COLD  
HOT  
1
3
2
XLR Balanced Wiring  
Pin 1 = Shield  
Pin 2 = Hot (+)  
1/4" TRS Insert Plugs and Jacks  
When patching the T231 into a channels  
insert jack, you may need to use a special 1/4" TRS  
connector that uses the tip to send the signal to the  
T231, and the ring to return the signal to the channel.  
The sleeve is the common ground (earth) for both  
signals. These are both unbalanced signals.  
Pin 3 = Cold ()  
1/4" TRS Phone Plugs and Jacks  
TRSstands for Tip-Ring-Sleeve, the three  
connection points available on a stereo 1/4" or  
balanced phone jack or plug. TRS jacks and plugs are  
used for balanced signals.  
SEND to processor  
ring  
“tip”  
(TRS plug)  
tip  
sleeve  
RING SLEEVE  
SLEEVE RING TIP  
This plug connects to the  
Channel Insert jack  
“ring”  
RETURN from processor  
TIP  
RING  
TIP  
1/4" TRS Insert Wiring:  
Sleeve = Ground  
Tip = Send  
SLEEVE  
1/4" TRS Balanced Wiring:  
Ring = Return  
Sleeve = Shield  
Tip = Hot (+)  
Ring = Cold ()  
RCA Plugs and Jacks  
RCA-type plugs (also known as phono plugs)  
and jacks are often used in home stereo and video  
equipment and in many other applications. They are  
unbalanced and electrically equivalent to a 1/4" TS  
phone plug.  
TIP  
SLEEVE TIP SLEEVE  
RCA Unbalanced Wiring:  
Sleeve = Shield  
Tip = Hot  
14  
 
Appendix C: Technical Info  
T231 Specications  
Frequency Response  
Indicators  
20 Hz to 20 kHz (+0, 1 dB)  
HI-PASS LED  
20 Hz to 50 kHz (+0, 3 dB)  
LOW-PASS LED  
CLIP LED  
BYPASS LED  
6 dB/12 dB Range LEDs  
POWER LED  
Audio Input  
Type:  
Active balanced XLR  
and 1/4" jacks  
Unbalanced RCA jack  
20 kbalanced  
AC Power and Current Requirements  
Impedance:  
15 kunbalanced  
Power Consumption: 12.5 watts  
AC Operating Voltages:  
Maximum Input Level: +21 dBu balanced and  
unbalanced  
U.S.  
120 VAC, 60 Hz  
Europe  
Japan  
Korea  
240 VAC, 50 Hz  
100 VAC, 50/60 Hz  
220 VAC, 60 Hz  
Audio Output  
Type:  
Active balanced XLR and  
1/4" jacks  
Fuse:  
315 mA @ 100-240 VAC  
Unbalanced RCA jack  
<600 Ω  
Physical Dimensions and Weight  
Impedance:  
Maximum Output Level: +18 dBu  
Height:  
Width:  
Depth:  
Weight:  
3.5 in/89 mm  
19.0 in/483 mm  
8.7 in/220 mm  
9.5 lb/4.3 kg  
THD+N @ 1 kHz, +4 dBu: 0.02% @ 1 kHz  
(all sliders at center position)  
Noise and Hum, unity gain:  
< 93 dBu  
< 103 dBu  
Common Mode Rejection:  
> 60 dB  
Crosstalk @ 1 kHz:  
Disclaimer  
Since we are always striving to make our products  
better by incorporating new and improved materials,  
components, and manufacturing methods, we  
reserve the right to change these specications at  
any time without notice.  
Graphic EQ  
Type:  
Frequency Range:  
1/3-octave Constant Q  
20 Hz to 20 kHz  
in 31 third-octave bands  
(ISO center frequencies)  
20 mm with center detent  
Off () to +17 dB  
40 Hz @ 12 dB/octave  
16 kHz @ 12 dB/octave  
Bypasses the graphic equalizer,  
Hi-Pass, and Low-Pass  
lter sections  
Sliders:  
Level:  
Hi-Pass:  
Low-Pass:  
Bypass:  
Range:  
6 dB or 12 dB  
15  
 
T231 Block Diagram  
This outlines the signal ow inside the T231.  
16  
 
1 1 5 V  
17  
 
Frequency Chart  
This chart shows the frequency range covered by various instruments and voices.  
Typical Frequency of each Instrument and Voice  
Middle C  
C D E F G A B C D E F G A B C D E F G A B C D E F G A B C D E F G A B C D E F G A B C D E F G A B C D E F G A B C D E F G A B C  
20 25 31 40 50 62 80 100 125 160 200 250 320 400 500 640 800 1K 1.3K1.6K 2K 2.5K 3.1K 4K 5K 6.2K 8K 10K 13K 16K 20K  
Human Hearing Range  
VOCAL  
Soprano  
Contralto  
Baritone  
Bass  
WOODWIND  
Piccolo  
Flute  
Oboe  
Clarinet in B flat or A  
Clarinet in E flat  
Bass Clarinet  
Basset Hom  
English Horn  
Bassoon  
Double Bassoon  
BRASS  
Soprano Saxophone  
Alto Saxophone  
Tenor Saxophone  
Baritone Saxophone  
Bass Saxophone  
Trumpet in C  
Trumpet in F  
Alto Trombone  
Tenor Trombone  
Bass Trombone  
Tuba  
Euphonium  
STRINGS  
Violin  
Viola  
Cello  
Double Bass  
Guitar  
KEYBOARDS  
Pianoforte  
Organ  
PERCUSSION  
Celesta  
Timpani  
Xylophone  
FREQUENCY  
20 25 31 40 50 62 80 100 125 160 200 250 320 400 500 640 800 1K 1.3K 1.6K 2K 2.5K 3.1K 4K 5K 6.2K 8K 10K 13K 16K 20K  
18  
 
TAPCO LIMITED WARRANTY  
G. LOUD Technologies warrants all repairs performed  
A. LOUD Technologies Inc. warrants all materials,  
workmanship and proper operation of this TAPCO  
product for a period of one year from the original  
date of purchase. If any defects are found in the  
materials or workmanship, or if the product fails to  
function properly during the applicable warranty  
period, LOUD Technologies, at its option, will repair  
or replace the product. This warranty applies only  
to equipment sold and delivered within the U.S. by  
LOUD Technologies or its authorized dealers.  
for 90 days or for the remainder of the warranty  
period. This warranty does not extend to damage  
resulting from improper installation, misuse,  
neglect or abuse, or to exterior appearance. This  
warranty is recognized only if the inspection seals  
and serial number on the unit have not been  
defaced or removed.  
H. LOUD Technologies assumes no responsibility for  
the quality or timeliness of repairs performed by  
TAPCO Authorized Service Centers.  
B. Failure to register online or return the product  
registration card will not void the 1-year warranty.  
I. This warranty is extended to the original purchaser  
and to anyone who may subsequently purchase  
this product within the applicable warranty period.  
C. Service and repairs of TAPCO products are to be  
performed only at the factory, OR at a factory-  
authorized service center. Unauthorized service,  
repairs, or modication will void this warranty.  
J. This is your sole warranty. LOUD Technologies Inc.  
does not authorize any third party, including any  
dealer or sales representative, to assume any  
liability on behalf of LOUD Technologies or to make  
any warranty for LOUD Technologies Inc.  
D. To obtain service, please follow the instructions  
found on page 13.  
E. LOUD Technologies Inc. and Authorized TAPCO  
Service Centers reserve the right to inspect any  
products that may be the subject of any warranty  
claims before repair or replacement is carried  
out. LOUD Technologies and Authorized TAPCO  
Service Centers may, at their option, require  
proof of the original date of purchase in the form  
of a dated copy of the original dealers invoice  
or sales receipt. Final determination of warranty  
coverage lies solely with LOUD Technologies Inc. or  
its Authorized Service Centers.  
K. THE WARRANTY GIVEN ON THIS PAGE IS THE SOLE  
WARRANTY GIVEN BY LOUD TECHNOLOGIES INC.  
AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS  
AND IMPLIED, INCLUDING THE WARRANTIES OF  
MERCHANTABILITY AND FITNESS FOR A PARTICULAR  
PURPOSE. THE WARRANTY GIVEN ON THIS PAGE  
SHALL BE STRICTLY LIMITED IN DURATION TO ONE  
YEAR FROM THE DATE OF ORIGINAL PURCHASE  
FROM AN AUTHORIZED TAPCO DEALER. UPON  
EXPIRATION OF THE APPLICABLE WARRANTY PERIOD,  
LOUD TECHNOLOGIES SHALL HAVE NO FURTHER  
WARRANTY OBLIGATION OF ANY KIND. LOUD  
TECHNOLOGIES INC. SHALL NOT BE LIABLE FOR  
ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL  
DAMAGES THAT MAY RESULT FROM ANY DEFECT IN  
THE TAPCO PRODUCT OR ANY WARRANTY CLAIM.  
Some states do not allow exclusion or limitation of  
incidental, special, or consequential damages or  
a limitation on how long warranties last, so some  
of the above limitations and exclusions may not  
apply to you. This warranty provides specic legal  
rights and you may have other rights which vary  
from state to state.  
F. TAPCO products returned to LOUD Technologies  
and deemed eligible for repair or replacement  
under the terms of this warranty will be repaired  
or replaced within thirty days of receipt by LOUD  
Technologies at our rainforest factory complex.  
LOUD Technologies may use refurbished parts for  
repair or replacement of any product. Products  
returned to LOUD Technologies that do not meet  
the terms of this Warranty will be repaired and  
returned C.O.D. with billing for labor, materials,  
return freight, and insurance. Products repaired  
under warranty at the factory will be returned  
freight prepaid by LOUD Technologies to any  
location within the boundaries of the USA.  
Please keep your sales receipt in a safe place.  
Mackie.and TAPCOare registered trademarks  
of LOUD Technologies Inc. Tweeqis a trademark of  
LOUD Technologies Inc.  
All other brand names mentioned are trademarks or  
registered trademarks of their respective holders, and  
are hereby acknowledged.  
©2004 LOUD Technologies Inc. All Rights Reserved.  
19  
 

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