Beginner's Gainclone guide

[gchrist]

Regulated power supply

Why is the power supply for the Gainclone not regulated? If it was regulated would the performance be better?

Thank you
George

 

[ukram]

The LM3875 has 120 dB supply noise rejection. According to my measurement with RMAA and soundcard, inverting gainklone has 82 dB S/N ratio, so regulating supply voltages does not make sense, as long as there is enough voltage to drive the speakers.

 

[pinkmouse]

Re: Regulated power supply

Why is the power supply for the Gainclone not regulated? If it was regulated would the performance be better?

Fred built one, and his results are here.

 

[li_gangyi]

I still dun get it...does the amp need positive negative supplies?? like +-30V ?? I'm sorry but the tranny wiring picture is down....one myside at least..wonder why??

 

[alvinlim]

Grounding scheme

Hi...

I am kind of confused on the grounding scheme. I understand the need for both star and power grounds. In the schematics, the power ground is connected to the DC 0V "G" which is correct.

Do I need to connect the Power Ground (PG) to "Earth" (the mains earth wire). In the beginners guide, it mentioned that we should connect the PG to earth via a 100 Ohm resistor and a 0.22microf capacitor. Why do we need that?

Regards

Alvin

 

[alvinlim]

speculation

just a guess - is the resistor to make cure that the P(G) is always positive with regards to the earth?