Gainlab Audio GLA-TC2 Use and care manual

Rt REQUIED TOOLS
1. For disassembly: 2mm Allen key (hex key)
screwdriver and 2.5mm Allen key (hex key)
screwdriver.
For trimming: 2-3mm flat head screwdriver.
2. Signal generator or other signal source with a maximum
output power of + 12dBu.
3. DC voltage meter, with expected accuracy:
minimum 4 1⁄2 digit ± (1% +2)
4. A device for measuring the root mean square
(RMS) value of AC voltage.
5. Audio analyzer recommended.
WARNING!
EACH ELEMENT OF THE PROCEDURE THAT WE DESCRIBED IN THIS DOCUMENT
ASSUMES A USER WITH PROFESSIONAL QUALIFICATIONS OR EQUIVALENT
KNOWLEDGE. IF YOU DON’T HAVE NECCESSARY KNOWLEDGE TO CARRY OUT ALL
OF THE OPERATIONS PROPERLY, PLEASE DO NOT ATTEMPT ANY MODIFICATIONS
INSIDE THE DEVICE, AS YOU MAY BE EXPOSED TO THE RISK OF ELECTRIC SHOCK
OR DAMAGE OF THE EQUIPMENT.
GAINLAB AUDIO WILL NOT BE REIALBLE FOR ANY PERSONAL INJURY
RESULTING FROM IMPROPER HANDLING!

Re REMOVE THE UPPER COVER

Version: GLATC2CalibrationManualV2.1
1. STEP - PREPARATION
1.1 The unit shall be disconected from mains!
1.2 Check the VU meters on the front panel. Adjust the VU meter with
the front panel screw to make it show the -20dB position as close
as you can.
1.3 Now you can connect the unit to mains. Also connect your input
and output signal cables.
1.4 Turn it on and wait 15 minutes to warm up the unit.
Note: The Attack, Release and Sidechain filter knobs are not used
through the setup process.
The following positions shall remain in the full process:
Attack – Fastest, Relase – Fastest, Sidechain Filter – Off
2. STEP - OUTPUT VU METER SETUP
Starting point:
Input signal : +4dBu 1kHz sinewave, on both channels
Switch positions: Mode-Bypass, Meter-Output meter
Measurement process: To measure: the VU meter on front panel
Adjust: VR15 and VR16 trimmer
Target: On both VU meters there shall be 0dB on the output scale

3. STEP - BALANCING
Starting point:
Input signal : +4dBu 1kHz sinewave, on both channels
Switch positions: Mode-Bypass, Meter- Output meter, Threshold MAX (left)

3.1 Bypass measurement (Left channel)
Switch Mode to Bypass.
Measurement process: Measure voltage between TP1 and TP2 points
Adjust: VR3
Target: to see 0V on volt meter
Error margin: 0.1V
3.2 Hicomp measurement (Left channel)
Switch Mode to HiComp.
Measurement process: Measure voltage between TP1 and TP2
points
Adjust: VR9
Target: to see 0V on volt meter
Error margin: 0.1V

Now go back to 3.1 and check if in Bypass mode you still measure 0V in between TP1 and TP2.
Most likely it will stay as you set up earlier. Repeat 3.1 and 3.2 if needed.
3.3 Bypass measurement (Right channel)
Switch Mode to Bypass.
Measurement process: Measure voltage between TP4 and TP5
points
Adjust: VR4
Target: to see 0V on volt meter
Error margin: 0.1V
3.4 Hicomp measurement (Right channel)
Switch Mode to HiComp.
Measurement process: Measure voltage between TP4 and TP5
Adjust: VR10
Target: to see 0V on volt meter
Error margin: 0.1V

Now go back to 3.3 and check if in Bypass mode you still measure 0V in between TP4 and TP5.
Most likely it will stay as you set up earlier. Repeat 3.3 and 3.4 if needed.
4. STEP - LEVELLING
Starting point:
Input signal: +0dBu 1kHz sinewave, on both channels
Switch positions: Mode-HiComp, Meter- Output meter, Threshold
minimum (full left), UNLINK
Measurement process: Adjust: VR1
Target: to measure +0.05dBu on the left output of the unit (not the
VU meter!)
Adjust: VR2
Target: to measure +0.05dBu on the right output of the unit
(not the VU meter!)
Error margin: 0.1dBu

5. STEP - SC LEVELLING
Starting pont:
Input signal : +0dBu 1kHz sinewave, on both channels Threshold 0dB,
mode – HiComp, UNLINK
5.1 step – Stage One
Measurement process: Stage ONE left
Measure: between TP8 (gnd point on volt meter) and TP15
Adjust: VR5
Target: measure +1.1V on a volt meter
Now, turn the VR7 counterclockwise until the end point (appx. 6 turnes)

Measure: between TP8 and TP15
Adjust: VR5
Target: measure +1.4V on a volt meter
Measurement process: Stage ONE right
Measure: between TP8 (gnd point on volt meter) and TP14
Adjust: VR6
Target: measure +1.1V on a volt meter
Now, turn the VR8 counterclockwise until the end point (appx. 6 turnes)
Measure: between TP8 and TP14
Adjust: VR6
Target: measure +1.4V on a volt meter

5.2 step – Raw tuning
Turn the Threshold to -9dB position. Switch to UNLINK.
Adjust: VR7
Measure: -3dBu on the left output
Error margin: +-0.1dBu
Adjust: VR8
Measure: -3dBu on the right output
Error margin: +-0.1dBu

5.3 step – Fine tuning
Turn the Threshold to -9dB position. Switch to LINK.
Adjust: VR7
Measure: -3dBu on the left output
Error margin: +-0.1dBu
Adjust: VR8
Measure: -3dBu on the right output
Error margin: +-0.1dBu

Switch to UNLINK.
Adjust: VR5
Measure: -3dBu on the left output
Error margin: +-0.1dBu
Adjust: VR6
Measure: -3dBu on the right output
Error margin: +-0.1dBu
Now keep watching the outputs and switch back and forward between LINK and UNLINK mode. If
there is a difference in the output signal which is greater than 0.1dBu then repeat the 5.3 step.
6. STEP – GR CALIBRATION
Starting point: Mode- HiComp, UNLINK, Threshold -9dB, meter - Reduction
Input signal: +0dBU 1kHz sine wave

Switch mode to Bypass!
Adjust: VR11 (for left channel) and VR13 (for right channel)
Measure: 0dBU on a VU meters
Switch mode to LoComp!
Adjust: VR12 (for left channel) and VR14 (for right channel)
Measure: -3dBU on a VU meters reduction scale
Go back to Bypass mode and check if it needs repeated adjustment until you see that the VU
meter works correctly.
THAT’S IT! YOU ARE DONE NOW.
YOU CAN LISTEN TO YOUR FAVORITE TRACK THROUGH THE UNIT FOR CHECKING SONICAL PERFORMANCE.
If you have further questions or stucked somewhere in the procedure then please reach GAINLAB AUDIO
through [email protected] .

• THE PROCEDURE WE DESCRIBED ABOVE PROVIDES THE EXPECTED VALUES FOR A DEVICE
EQUIPPED WITH VACUUM TUBES PROVIDED BY GAINLAB AUDIO.
• IF YOU STILL WANT TO USE YOUR EQUIPMENT WITH 3RD PARTY TUBES, MAKE SURE THAT THE
TECHNICAL PARAMETERS OF THE VACUUM TUBES THAT YOU PLACED IN THE TUBE1, TUBE2 SOCKET
AND THE TUBE3, TUBE4 SOCKET ARE APPROXIMATELY THE SAME. MATCHED PAIR TUBES ARE
SUGGESTED TO USE.
• IF YOU DO NOT USE VACUUM TUBES WITH THE SAME TECHNICAL PARAMETERS, THE CALIBRATION
PROCESS WILL NOT BE PERFORMED CORRECTLY!
• THE TECHNICAL PARAMETERS OF THE VACUUM TUBES CAN CHANGE SIGNIFICANTLY IN THE FIRST
24-48 HOURS. IT IS RECOMMENDED TO REPEAT THE CALIBRATION PROCESS AFTER THIS “BURN-
IN” PERIOD.
• THE VACUUM TUBES PROVIDED BY GAINLAB AUDIO HAVE ALREADY UNDERGONE THIS “BURN-IN”
PROCESS.

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GAINLAB AUDIO 2023.
www.gainlabaudio.com