OCL 120 WATTS LANEY is a Guitar Power Amplifier with some feature such as Acoustic channels and Electro channels that you can choose one. For acoustic channels there are 6 Equalizer that can be used to evaluate the sound of your guitar.
Table of Contents
See the pict HERE.
SCHEMATIC DIAGRAM POWER SECTION OF OCL 120 WATTS LANEY
This is an edited version of LANEY
From the circuit above, its consists of some blocks:
- Differential Preampifier,
- Voltage Amplifier,
- Servo Driver,
- Over Current Protection,
At the input side, there is 3.9V Zener Diode available which is serves as an input signal limiter.
It also there is a 15VDC zener Diode as a voltage stabilizer for supply in this differential amplifier feed circuit.
GAIN of this circuit depends on the ratio of values between R11 and R12 or it’s about 100 times of gain.
The voltage amplifier T5 uses MPSA42.
The T6 servo driver uses BC 237 transistors where at the Base pin there is a 4K7 Trimpot which serves as a setting for idle current of the Final Power Transistors.
Its power amps also have the C5 elco booster capacitor which serves as positive feedback to mix in the voltage amplifier.
The OCP transistor here is uses BC237 paired with BC 307 (T7, T8).
This transistor has the task of if there is excess current in the R23 or R24, this will activate the T7 and T8 transistor bases to limit the signal to the power amplifier controller.
The amplifier driver here uses TIP31C and TIP32C pairs that have power capacities of up to 30 watts.
Finally, there are the T11 and T12 transistors that use TO-3 case, which is a quasi-pair that has a capacity of up to 150 watts.
NOTE FOR OCL 120 WATTS LANEY
By applying a voltage of 50 volts symmetrically, it is still possible for transistors to produce power up to 150 watts but at a load of 8 ohms.
When using a 4 ohm load, it is not recommended to do a full load for this amplifier because it is feared that overheating will occur when the signal is high level input.
Actually, you can modify this circuit by using another final transistor as long as it is a type of NPN.
For example, using a transistor 2sc 5200, even your voltage rises, there is no problem.
It’s just that you have to know the transistor calculation needed and how much supply voltage is needed too.
For example, this circuit is actually capable of up to 80 volts DC for supply, but you must have a final transistor of 5 or more pairs.
And the risk is that this power amplifier will output much more power but the current supply also requires more as well.
Final Power Transistor OCL 120 WATTS LANEY is using 2N3773 that can make power output up to 150 Watts (DATASHEETS). Below the transistor 2N3773:
VARIOUS POWER AND Mixer Schematic Diagram inside this blog are LOOK HERE.