Power Conditioner Advice please...

I would be grateful for advice from the forum with regard to the following:

My system sounds significantly better in the evening/night than during the day and given that I live in a busy commercial area it would seem likely that I need to clean up the power. 

Ultimately, I will buy an AC regenerator but do not currently have the budget for that. I am therefore looking at a power conditioner and which I hope to buy pre-owned for under $/£1,000.

Given my amps draw a large wattage (peak 400w into 4ohms) I am nervous about placing a conditioner between them and the mains.

The other components:

1.     Auralic Aries - has its own external linear power supply.

2.     DEQX  -  “Nine separate power-supply regulation stages  including four that provide the main analog rails deliver extremely low measured distortion....”

Where do you think I would be best to apply any power conditioning?

Any other suggestions welcomed.

Thanks very much