This is the circuit diagram of stereo tube preamplifier, give you high gain with high performance output. This circuit should work fine with a 6J5, 12SX7, 6CG7, or 12AU7 as the lower tube, and a 6BX7, 12B4, or triode-connected 6BQ5 as the upper tube. Any of the miniature TV dual triodes such as 6DE7 or 6EW7 can serve as both top and bottom triodes since they contain a medium-mu and a low-mu section. (This wouldn't be my choice, since the octals seem to sound better, but you may choose the tubes you like.) Tube Preamplifier Parts List: R1,R5 = 100 1/4W carbon R2,R6 = 100 1W metal film R3 = 1M 1/4W metal film R4 = 10k 25W wirewound R7 = 10k 1/2W metal film VR1,VR2 = Part of Alps quad volume/balance control C1 = 2uF 400V polypropylene C2 = 10uF 400V polypropylene V1 = 12SN7GT (GE) or 6SN7GT (see text) V2 = 6BL7GT (GE) This circuit require special power supply circuit. The power supply is regulated, has slow warmup inherent in its operation. The power supply for this tube preamplifier...

This is the diagram of 2x6W stereo audio amplifier based LA4440 power IC. Actually, the LA4440 can be used in both stereo mode and mono (bridge) mode, but the circuit presented in this post is LA4440 in stereo mode. The recommended power supply is 13.2V, while the maximum voltage rated at 18V. LA4440 Features: Built-in 2 channels (dual) enabling use in stereo and bridge amplifier applications. Dual : 6W´2 (typ.) Bridge : 19W (typ.) Minimum number of external parts required. Small pop noise at the time of power supply ON/OFF and good starting balance. Good channel separation. Good ripple rejection : 46dB (typ.) Low distortion over a wide range from low frequencies to high frequencies. Small residual noise (Rg=0). Easy to design radiator fin. Built-in protectors. Built-in audio muting function. Thermal protector Overvoltage, surge voltage protector Pin-to-pin short protector

This is the circuit diagram of 50W power amplifier circuit which built based on single power amplifier chip of STK084. It's an well-known old IC for audio frequency (AF) amplifier. This circuit requires dual polarity / split power supply with maximum supply of ± 50. The recommended supply is ± 35 / 2-3A DC current. You may use this split power supply circuit for the amplifier. Use 28V center tap transformer to get about ± 36V output. Technical Details: Power output: 50W RL : 8 Ohm TDH : 0.2 % Rin : 52K Gain : 26.4 dB Noise : 0.3 mV Take a note that heatsink is required to be mounted on the power IC since it will going to hot when operated and deliver high power output (high audio volume level).

Here the 50W audio amplifier circuit diagram. The amplifier is based ICL8063. This a good amplifier circuit which is easy enough to built.. This circuit can be connected by radio, TV, stereo or other devices. The circuit is also featured with inputs for the record player, guitar, microphone, and others. If you add low pass filter at the input, it will work like a mini-subwoofer. Circuit scheme presented will guide you in 50W amplifier construction, good luck. The power supply is splitted type, already added on above circuit diagram . Components List: R1 = 200R 1/4W R2 =200K 1/4W R3 = 30K 1/4W R4 = 1K 1/4W R5 = 5K 1/4W R6, R9 = 1M 5% 1/2W R7, R8 = 0,4 ohm 5W R10 = 10K Pot R11, R12 = 51K 1/4W R13 = 47K 1/4W C4, C6, C5, C7, C8 = 1nF C9 = 50pF C10 = 0,3uF C11, C12 = 10000uF/50V U1, U2 = IC 741 Op Amp U3 = ICL8063 Q1 = 2N3055 NPN Power Transistor Q2 = 2N3791 PNP Power Transistor D = 250V 6A Bridge Rectifier T = 50V Center Tapped 5A Tranformer C1 = 100uF/35V F1 = 2A Fuse C2 = 11nF SPEAKER ...

This is the circuit diagram of enhanced Hafler Matrix surround sound decoder. The above schematic can be a basic technique to attain exactly the same factor (with some extra rewards) at line level (i.e. prior to the signal reaches the power amplifiers - in a bi-amped method, this circuit should be in between the preamp along with the electronic crossover). The extras obtainable are readily apparent: Wiring is simplified (despite the fact that extra power amplifiers are necessary) We now have a centre channel signal accessible Provision for a mono signal to a sub-woofer is simple Though there have been comparable circuits published more than the years, this can be slightly unique in several locations. I wanted to prevent getting any active electronics inside the key Left and Right channels, due to the fact this eliminates any possibility of sound degradation because of the introduction with the op-amps. The input impedance of 50k won't pose an issue for any pre-amp (such as valve so...