hifi engine

Technics SU-Z45 and ST-Z25L


I've just bought those 2 hifi components :

Technics SU-Z45 amplifier

Technics ST-Z25L tuner

Are the provided with double isolation (class 2) or I need to connect them to Ground in order to avoid any electrocution ? Because I see that on each component there is a GND connection but I'm not sure that is really necessary for safety.

Anyone knows ?

If I need to do a ground connection how can I proceed ?

Thank you in advance

Re: Technics SU-Z45 and ST-Z25L

The "ground" terminal in the tuner (ST-Z25L) serves solely for connecting the ring of the 75ohm antenna cable for FM reception.
You should not connect it to any power ground lines.

Re: Technics SU-Z45 and ST-Z25L


There is no need to connect the ground terminal to the ground of your electrical system. The units are perfectly safe without it connected.

The purpose of the ground terminal is to connect it to other audio equipment to eliminate ground loops. Ground loops are usually the source of hum present in the audio. By connecting the equipment using standard cables there USUALLY isn't a need for additional grounding. The exception is the turntable / phono. Some turntables will need a ground terminal connected as well as signal cables. Other turntable do not need it connected and will in fact produce hum due to the ground loop situation and the very low signal levels inherent in the phono cartridge. You can determine by trying both and seeing which one produces the least hum.