Help on power supply for Chip Amp & Op Amp

[pra3718]

Please find attached schematic.

Transformer 18-0-18 = Rectifier Bridge = 4700uf Cap = 0.1uf = Regulator = 0.1uf
25(+/-) is for LM1875
18(+/-) is for NE5532 preamp

1) Correct way to separate 0V to Ground by 1R resistor, before regulator or after regulator ?

2) I want +5V supply, So where should I use 7805 Regulator ?

 

[AndrewT]

Neither.
Read
Audio Component Grounding and Interconnection - diyAudio

 

[donpetru]

Although the LM's datasheet is recommended + /-25Vcc, I would recommend the LM fed less. It is much safer with + /-20Vcc.

 

[availlyrics]

LM1875 ratings +/- 25V for 4ohms, +/- 30V for 8ohms. Don't use any devices near Vcc max.Keep a 10-30% margin e.g. I use 2 independent SMPS for LM1875 chipamp bought @ Rs 350/- each having rating 21V/4.0A. Connected in series resulting +/- 21V/4.0A they shake foundations! Using transformer/rectifier/linear regulators only increases heat losses.For +5V(assuming you are using generic USB mp3 player) I suggest you use mobile charger adapter. Simply cut the end wires & solder any DC pin of your choice.

 

[pra3718]

Thank you all,

@Andrew : I tried to copy from the link. Pluto electronics

Instead of using 2.2R I am using 1R. Your "Audio Component Grounding and Interconnection" link is good I am reading....

@availlyrics : You got the point,

1) 25(+/-)VDC I want for LM1875
2) 18(5/-)VDC for NE5532 preamp]
3) +5VDC for USB mp3 player.

Mobile charger adapter is good choice, what is the disadvantage to pick +5VDC from main power supply.

 

[AndrewT]

Thank you all,

@Andrew : I tried to copy from the link. Pluto electronics

Instead of using 2.2R I am using 1R. Your "Audio Component Grounding and Interconnection" link is good I am reading....

where are you proposing to place the resistor?
I have already said

neither

 

[pra3718]

Updated.. Now is it correct ?