sprexumn
Newbie level 1
simple voltage controlled amplifier
Hi. I'm looking for someone to build a relatively simple circuit for me.
I'm the owner of a 2004 Toyota Prius, and I'm trying to upgrade the audio system, replacing the amplifier and speakers. The problem is that the factory amplifier in my "JBL premium" sound system is what controls the volume and fader. If I just hook another aftermarket amp in place of the factory amp from the balanced fixed level signal from the head unit, I won't have control over the volume or fading. I know I could add my own passive line level volume control, but I'd prefer to use the factory volume and fader.
So to get around this issue, I would like a circuit that would use the old factory amplifier just to get volume/fader control. It would work like this:
A sine wave or some other constant-amplitude signal gets sent into the factory amplifier input. The front and rear outputs from the amplifier are then converted to DC voltages with a capacitor, to use as the control level to a voltage controlled amplifier (well preamp actually) that would simply serve as a level control. The input to the VCA would be the signal from the head unit, and the output would go to the aftermarket amplifier. There would need to be four channels of VCA, Right and Left for Front and Back.
I don't really have any significant experience with analog electronics, although I did earn a degree in EE a dozen years ago, my circuit design skills are pretty pathetic, and don't have the necessary fabrication/debugging equipment. So I am wondering if there is someone who would be interested in taking on this project. I could pay perhaps a couple hundred dollars. And there are many thousands of other Prius owners (not to mention other car makes) who run into the same issue and would probably be interested in such a solution.
If anyone is interested in working on this or has ideas for where to turn, let me know at sfsprs[hyphen]audio@yahoo.com (where [hyphen] needs to be replaced with a real - character).
Thanks!
Hi. I'm looking for someone to build a relatively simple circuit for me.
I'm the owner of a 2004 Toyota Prius, and I'm trying to upgrade the audio system, replacing the amplifier and speakers. The problem is that the factory amplifier in my "JBL premium" sound system is what controls the volume and fader. If I just hook another aftermarket amp in place of the factory amp from the balanced fixed level signal from the head unit, I won't have control over the volume or fading. I know I could add my own passive line level volume control, but I'd prefer to use the factory volume and fader.
So to get around this issue, I would like a circuit that would use the old factory amplifier just to get volume/fader control. It would work like this:
A sine wave or some other constant-amplitude signal gets sent into the factory amplifier input. The front and rear outputs from the amplifier are then converted to DC voltages with a capacitor, to use as the control level to a voltage controlled amplifier (well preamp actually) that would simply serve as a level control. The input to the VCA would be the signal from the head unit, and the output would go to the aftermarket amplifier. There would need to be four channels of VCA, Right and Left for Front and Back.
I don't really have any significant experience with analog electronics, although I did earn a degree in EE a dozen years ago, my circuit design skills are pretty pathetic, and don't have the necessary fabrication/debugging equipment. So I am wondering if there is someone who would be interested in taking on this project. I could pay perhaps a couple hundred dollars. And there are many thousands of other Prius owners (not to mention other car makes) who run into the same issue and would probably be interested in such a solution.
If anyone is interested in working on this or has ideas for where to turn, let me know at sfsprs[hyphen]audio@yahoo.com (where [hyphen] needs to be replaced with a real - character).
Thanks!
