Arduino nano control added to mini Crescendo overhaul

After almost 40 years of reliable service my self constructed mini Crescendo received a total recap, dual PSU (Toroidal transformers and Rectifier + Smoothing capacitors),  an Arduino nano controller with an 40X02 LCD display, phones output whose presence is indicated on the display, dual moving coil output power indicators with automatic illumination according to ambient light conditions, temperature PWM controlled FANS for the heat-sink and the box (temperature and PWM duty cycle are indicated on the display) and full report on the status of powering on and powering off procedure as well as indication of failures due to DC presence in output or overheating. Almost all power on and power off  timings are controlled by the Arduino nano.

Many circuits used are of Elektor origin such as the phones and DC protection modules emanating from the original Crescendo Accessories back in the '80s. the mains noise suppression module is from an article of 2004 about Clarity Amp, the Moving Coil output power indicator module is an adapted version of an idea publicized by Mr. P de Bra in the July/August 1979 issue of Elektor magazine, the main Power Amp PSU emanates from the HEXFET PA of 1993, the mains on delay for toroids was in a Elektor magazine issue back in "97.

All these fine modules were amalgamated with some self designed auxiliary modules to form an Arduino nano controlled Power Amplifier.

The front face support for the LCD and Moving Coil meters, was designed by me using the now obsolete but still usable 123D Design and printed in my home 3D printer (Creality Ender 6).

The tools used were the Kicad 5.XX and Kicad 6.XX PCB design tools and the programming was done through the FlowCode V.8 software tool since my experience with code writing is limited to Z80 Assembly language (during my student years). All the PCBs were made by hand in the traditional old way (etching resist pen and etching fluid).

The result is, to my ears, still impressive as the first day I powered the mini Crescendo up back in 1986.

Thank you Elektor for the many constructive hours you have provided to me and certainly will continue to do so.