1 channel, 1 LED color Organ

Greetings

I found the attached circuit diagram late last night and I have a few questions I hope someone might be able to answer.




I know lower half of the circuit works, the audio transformer - 4.7K pot to single LED circuit works, but the circuit is no where strong enough to fire up a super bright LED or multiple leds..

What I would like to know is if I could replace the 3-12v lamps to 3-5v LED's and the 25VAC transformer to a 12VDC power supply, What would you change the SCR value to ?

My first thought was a L7805 voltage regulator but I think I am starting to mix apples and oranges.

I wont have access to test or try this circuit for alt least 2 weeks, but I hope one of you guru's here might guide me in the right direction.

I'm NOT an expert in this in any way, but I do like to tinker.

Any help would be greatly appreciated.


Cheers
Aurbo