Straightening 3A diodes bridge circuit is connected to.

The circuit is located on the 2 x 4700μF 63v capacitor filter hood. This power supply circuit for a single channel and two channels and two transformers to be installed in two separate feed circuit. However, if you use the one constant in this amplifier 5A transformer may be sufficient.

The circuit is very simple. MPSA56 (= BC556) s differential input pair, BD139 and BD140 s pairs in the current drive. These transistors have been selected because of the quality of sound as a result of long experience.
The complementary pairs of output transistors Hitachi 2SK1058 and 2SJ162 MOSFET'leridir conjugate. These are some expensive transistörlerdir (10 €), but none of equivalents do not recommend it because it is not for audio applications. The gate voltage of MOSFETs, and this limitation has diyotlarına provide some fault tolerance and protection. However, for a better protection to the speaker I would recommend to add insurance 3A slow. * (1)
One advantage of using the MOSFET output stage; secondary crash (secondary breakdown) is not stable, and all kinds of amplifier remains at ambient temperature. Serenity of the circuit current is around 210mA. This is because the circuit to the level of approximately 8W Class A Class B is passed to work after that. As a result, the average listening on a very low distortion is provided.
Simple design of a printed circuit board designed to connect to the four mounting holes and added directly to the cooler. MOSFETs also facilitate the work of the PCB assembly will be toast from the refrigerator, compact, solidly built and will have a design for an amplifier transistor, which is a big advantage.
Input / outputs if the future .. Signal input of J1, J2 signal chassis. Speakers connected between J3 J7. 35V Transformer in connection J6, 0 J4, J5 will be as if the other 35V.
Amp also has a modular structure, prompted a bridge connecting two 8 ohm load, 250W RMS power amplifier can be configured to convey. For this, the first amplifier input signal is connected to J1 and J2, J1 and J2 s second amplifkatörün by a short circuit, the first, second amplinin J8 J3 tip connected to the speaker output. In this case, two amplifier's speaker output terminals to be connected J3'lerinden to be taken, and J7.
While there is a deterioration in the bridge mode, no sound study, up to 16W of class A must not forget that run. However, you must not forget that this is a bridge amplifier and 300W continuous power output of at least one speaker connected to the handle. In this case, it is useful to choose the output fuse 8A.

Amplifier designed and ran a lot of about 40 years. I saw that the very high quality filter capacitors with low equivalent resistance as a result, constitute a change in sound quality. For example, you can try to see Nichion Gold series, but you get better quality results in a capacitor or Hitano'dan Rubicon will not be different.

Note:
Directly to the output transistors of the circuit under pressure vidalanacaktır cooler. Therefore, this process will be fixed when the printed circuit board. Insulator and silicon grease between the cooler transistors must be banished. Otherwise you will short circuit the supply terminals.

CN: * (1) transistor amplifiers as a general rule, there is no protection circuitry. This circuit is the need to protect the output against excessive movements and as well as not have DC'e.

CN1: This application is definitely not suitable for beginners. Friends, I would recommend starting a new project in the No. 1.

Component List
Taylor 0R22 5.0W Resistor (R19, R25) 2 Units
1K0 0.25W 5% resistor (R9, R10) 2 Units
1K2 0.25W 5% resistor (R14) 1 Piece
1N4148 diode (D1, D2) 2 Units
1N5404 diode (D3, D4, D5, D6) 4 Units
2K2 0.25W 5% resistor (R23) 1 Piece
Power MOSFET 2SJ162 (TO3P sheath) (Q3) 1 Piece
2SK1058 Power MOSFET (TO3P sheath) (Q5) 1 Piece
3K9 0.25W 5% resistor (R12, R13) 2 Units
10R 1.0W 5% (R24) 1 Piece
10K 0.25W 5% (R8) 1 Piece
10u 16V capacitor (C1) 1 Piece
47k 0.25W 5% resistor (R2, R3, R15, R16) 4 Units
Capacitor 47U 35V 8mm (C2) 1 Piece
82P 50V 5mm Ceramic Disc Capacitor (C5, C6) 2 Units
100N 50V Ceramic Disc Capacitor (C3, C7) 2 Units
470R 0.25W 5% resistor (R5, R6) 2 Units
470P/50V 5mm Ceramic Disc Capacitors (C4) 1 Piece
4700u 25mm 63V Radial Capacitor (C8, C9) 2 Units
Transistor BD139 TO 225 (Q9, Q10) 2 Units
Transistor BD140 TO 225 (Q7, Q8) 2 Units
Transistor MPSA56 TO 92 (Q1, Q12) 2 Units
Transformer 40V - 0 - 40V 3 A 1 Piece