I'm adding VU meters to my First Watt F5v2. The meter drive board needs 12-18V AC or DC.
The power supply in the amplifier outputs 27.5V to the amplifier boards.
Looks like there are three ways I could power this board:
#1) Drop the 27.5V in half with a simple resistor circuit (attached)
#2) Use a small 120V to 12V transformer within the amplifier chassis
#3) Use an outboard 12V "Wall Wart" and keep all this stuff outside the chassis
What would be the best approach with the least introduction of possible noise?
Thank You
The power supply in the amplifier outputs 27.5V to the amplifier boards.
Looks like there are three ways I could power this board:
#1) Drop the 27.5V in half with a simple resistor circuit (attached)
#2) Use a small 120V to 12V transformer within the amplifier chassis
#3) Use an outboard 12V "Wall Wart" and keep all this stuff outside the chassis
What would be the best approach with the least introduction of possible noise?
Thank You
Attachments
A better option:
Make a simple regulator circuit using a LM1085 (low dropout regulator) to supply your meter drive boards from the main 27.5V.
Download a copy of the datasheet from TI.com. The basic circuit is on the first page.
Edit: ZM beat me to the answer. A 7815 regulator would also work very well.
Make a simple regulator circuit using a LM1085 (low dropout regulator) to supply your meter drive boards from the main 27.5V.
Download a copy of the datasheet from TI.com. The basic circuit is on the first page.
Edit: ZM beat me to the answer. A 7815 regulator would also work very well.
Using a regulator will isolate the rest of the amplifier power supply from any noise that might be generated by the VU meter drive board. And it will ensure that the VU meters have clean power.
Well, I found a nice little regulated 120V to 12V DC power supply in my junk box.......As we say in Boston..."Works the Pissah!".....Absolutely no noise introduced to the amplifier. Meters are working great......
Attachments
Glad it works.
Anyway consider the 7815 regulator option: does not need a separate plug into a wall outlet, can be built inside your amp and will use about a stamp sized board with 2 or 3 components.
Anyway consider the 7815 regulator option: does not need a separate plug into a wall outlet, can be built inside your amp and will use about a stamp sized board with 2 or 3 components.
Thank you for all the suggestions! Greatly appreciated.
As you can see, I'm not plugging the power supply into the wall. It is mounted to the back of the cabinet and hard wired.
As you can see, I'm not plugging the power supply into the wall. It is mounted to the back of the cabinet and hard wired.
ZM is Chicken
putting that Drek ditto by input RCA .......... I'm definitely not brave enough for same move
putting that Drek ditto by input RCA .......... I'm definitely not brave enough for same move