Stereo preamplifier with tone controls

It is a pre amplifier and audio control unit which will be a useful complement to our circuit amplifier makes. It is extremely easy to build special Philips TDA1524A due to the use of an IC.

Because it uses the control voltage, linear single gang can use pots which lowers costs and reduces Fehler.Es monitoring of switches control or microprocessor, if desired.

Specification:

DC input: 15V DC Versorgung or 12V
DC battery.50 mA min
Maximum output power: 3 V RMS
Maximum input power: 300 mV, G = 20 dB 3V RMS, G = 0 DB
Entry Z 10 k ohms
Z 300 OHM output frequency or: 50 kHz + /-1 dB
THD 1 kHz: 0.1% to 1 v output signal noise ratio: 80 dB, G = 0 dB
Bass boost/cut ~ 15 dB at 50 Hz
Triple inch cut blow ~ 15 dB at 15 kHz



Click here for Datasheet TDA1524A IC - original Audio Kit

Stereo preamplifier with bass boost

This preamp circuit was designed around from CD player, tuner, Tape Recorder, etc., offers 4 AC voltage gain at least sensitive power amplifiers to cope. Fi House modern devices often with small loudspeaker cabinets installed, the low frequency range rather sacrificed. This circuit includes a low amp to overcome this problem. You can use a variable resistance, Bass Boost 0 maximum value + 16 dB @ 30 Hz. If a fixed maximum necessary boost value variable resistance can be omitted and replaced by a switch.

The parts list:

Notes:

• Diagram shows left channel only, but R1, R2, R3 and C1, C2, C3, which are common to both channels.
• For stereo operation P1, P2 (SW1), R4, R5, R6, R7, R8, and C4, C5, C6, C7 should be doubled.
• Figures in parentheses indicate PIN for the right IC1 channel connections.
• A protocol for P2 type ensures a more linear regulators of bass boost.
• Need for a simple boost with launch of thumb out - process P2 shall be omitted and SW1 added, as shown in the diagram.
• Bipolar stereo operation must be an SW1 type.
• Please note that the SW1, increasing use is if the switch is open and turning off closing switch.

Source: stereo with bass boost preamplifier

Audio preamplifier with tone controls

The margin of sensitivity and an overload of audio preamplifier circuits are designed to cope with more modern music program sources such as CD players, tape recorders, iPod, computer output audio, tuner etc... Source select switch and input connectors do not appear, and their number and their arrangement are left to the manufacturer.

A margin overload audio preamplifier for pre amplifier volume control extremely high input was provided input.After a gain level converter impedance (T1) negative feedback type low Baxandall and treble EQ step was ajoutée.Comme some very low noise (5.6 times) win this phase must provide, phase characteristics implementiert.Diese two transistors with FET input circuits was also excellent THD numbers "their" 4V RMS output and an exit low impedance, needed to drive right Mini MosFet power amplifier, but can be used for other purposes.

Audio preamplifier The parts list:

R1 = 220 K 1/4W resistance
R2 = 100 K 1/4W resistance
R3 = 2 K 7 1/4W resistance
R4, R5 = 8 K 2 resistors 1/4W
R6 4 K = 7 1/4W resistance
R7, R8, R13 = 2 K 2 resistors 1/4W
R9 = 2 M 2 1/4W resistance
R10, R11 = 47 K 1/4W resistance
R12 33 K = 1/4W resistance
R14 = 470R 1/4W resistance
R15 10 K = 1/4W resistance
R16 3 K = 3 1/4W resistance (see notes)

= C1, C2, C9 470nF lo polyester capacitors
C3, C4 = 47nF lo polyester capacitors
C5, C6 = 6n8 lo polyester capacitors
C7 = 10µF lo electrolytic capacitors
C8, C10 = 22µF 25V electrolytic capacitors
C11 = 470µF 25V electrolytic capacitors (see notes)

Q1, Q3 BC550C input voltages 100mA low noise = gain high NPN transistor
Q2 = multifunctional N-channel FET 2N3819