Schematic & Wiring Diagram

Here the schematic diagram of mic preamplifier which build based on operational amplifier TC251. The TLC251 is operating in low bias. The circuit works with only 1.5 V supply draws electric current of only 10 mA, so the battery operation will be prefered. Circuit frequency response is 3dB, 27 Hz to 4.8 kHz.



Frequency Response:


The TLC251 are low-cost, low-power programmable operational amplifiers designed to operate with single or dual power supplies. Because the input common-mode range extends to the negative rail and the power consumption is very low, this chip is ideally suited for battery-powered or energy-conserving applications. A bias-select pin can be used to program one of three ac performance and power-dissipation levels to suit the application. The series features operation down to a 1.4V supply and is stable at unity gain.

Download the TLC251 datasheet document from the following link:
» Download link

This is the circuit diagram of stereo tube power amplifier. It applies 3 types of tube that are 2 6SF5 GT high-mu triodes, 1 5Y3 GT vacuum rectifier, and 2 6K6 power beam amplifiers. The Audio input can be from any two-channel line level device such as a television, CD player, or VCR. It is of the tube type, using only 5 tubes total with no more than about 45 Watts power consumption from the outlet.


Components List:
R1,R10,R13 = 2.2M Ohm Potensiometer
R2 = 470K Ohm
R3 = 1M Ohm
R4 = 220K Ohm
R5 = 330 Ohm 2W Resistor
R6 = 220K Ohm
R7 = 2.2M Ohm
R8 = 1M Ohm
R9 = 720 Ohm 20W Resistor
R11 = 33K Ohm
R12 = 22K Ohm
C1,C9 = 4nF 400V Capacitor
C2 = 50nF 600V Capacitor
C3 = 20uF/25V
C4 = 10nF 400V Capacitor
C5 = 200pF 400V Ceramic Disc Capacitor
C6,C7 = 15uF 450V Capacitor
C8 = 15uF 400V Capacitor
T1 = 117V Primary, 350VCT Secondary, 6.3V Secondary, 6.3V Secondary
T2 = 7600 Ohm Primary, 4 or 8 Ohm Secondary
SW1 = SPST Switch
SP1,SP2 = 12" or smaller, 4 or 8 ohm speakers
MISC = 5 tube sockets, 2 RCA jacks, PC board or chassis, wire, knobs, etc.

Stereo Tube Power Amplifier Circuit Notes:

1. C8 is for radio interference suppression and may be omitted.
2. The 6V6 GT tube may be substituted for the 6K6 to lower power requirements.
3. The 5Y3 GT tube should be mounted in a vertical position and be well ventilated. The 6K6 and 6SF5 tubes can be mounted in any position.
4. The power supply portion of this unit may be used for anything requiring 290-320v DC up to about 3 amperes.
5. Controls should have an audio taper.

Circuit Source: http://english.cxem.net/amplifier/amplifier13.php