Vermes
Advanced Member level 4
It is an amplifier of good quality without unnecessary additional features such as tone control. It consists of the power amplifier, selector with 4 inputs, remote control and analog meter.
Electronics: SymAsym boards in 1.0 version, 1% resistors (beyschleg/vischey), capacitors (SilverMICA, Wima), semiconductors: Toshiba 2sc/2sa and On semi.
Selector with gain control potentiometer is ALPS RK27 2x 50k to shorten the signal path. Bistable relays applied in the selector have a magnet, so they can be turned on and off by a pulse.
Typical topology of dual-mono type amplifiers was applied in this design. Separate supply for each channel: transformer from Radmon ts180/7, filtering 6x3300uF Samsung, fast rectifying diodes.
At such supply, the amplifier has a power: 60,5W/8ohm and 81W/4ohm, RMS power measured on resistance load at sine signal of 1kHz.
There is also an additional power supply and a driver for stepper motor. Headphone amplifier was based on TPA6120A. The fuse of amplifier (speakers) was made on upc1237. Atmega8 controls the whole device. Meter was removed from an old YAMAHA cassette player.
Functions:
The amplifier can be controlled by an IR remote control, it can be turned on and off. There is also Sleep function – the amplifier is turned off after 30 minutes. You can control the volume and select source of signal. To save energy, you can switch only that device, which is currently used. There are three power sockets in the back of the amplifier to connect other devices. Each output has its own relay, which can be controlled together with the outputs selector. When you select the CD player, voltage is fed only to the CD player output. The selection of input is indicated by stronger illumination of the button of selected input.
Housing:
It was designed in CAD SolidWorks.
The housing was screwed and all the components were assembled on plyamid spacer bushes with M3 thread. Elements of the housing were made of 1,5mm thick stainless steel, except the front panel, which was made of PA11 aluminum (4mm thick). Everything was laser-cut and bent on a press brake.
Front panel, volume knob and switch button were anodized in black, legs were anodized in satin (natural) to protect aluminum against oxidation. Inscriptions on the front panel were done on a CNC miller. Inscription on the rear panel can be done in thermal method.
Link to original thread - Zintegrowany wzmacniacz mocy SYMASYM DUAL-MONO
