Hello all,
I am a first time poster, and really don't know much about electronics, but I created a project for myself last year that I want to upgrade.
What I am doing is using an dual opamp (TL082 from Radio Shack) as a voltage follower in a project box in my car, between a Harman Kardon Drive+Play ipod interface, and a ground loop filter. I am doing this at someone else's suggestion because of an apparent impedance mismatch between the output of the HK unit and the GLI filter. This mismatch creates a high-pass filter, so it cuts all of the bass response out of my audio.
I am using the GLI filter because my car (a 2007 Camry Hybrid) seems to have an inherent problem with the 3.5mm aux input if ANYTHING is plugged into it, as well as being plugged into power (12v accessory power). There is an audible high pitch whine that you can hear at even low or moderate volume levels. The filter DOES remove the noise, but as I said above, the filter also removes bass.
The opamp circuit is being fed the output of the HK unit (1V max) audio signal, and I am powering the opamps with a pair of 9v batteries arranged to provide me with a +/-9 volt reference (and ground at the the zero point). I also included a 12v relay in the box to disconnect the 9v batteries when the ignition is turned off. I would like to eliminate the batteries, since I seem to get nasty distortion if the batteries are even slightly discharged.
I searched these forums and found a reference to a surplus site that has a 5v input, +/-12v output. This is compact, but I think I would need a regulator to drop the input voltage from the level of the cars accessory voltage to 5v. Is this difficult? I don't know much about regulators, but I suspect I can read up on them and figure out how to get regulated 5v from 12v.
What I am wondering about is the dc/dc converter. Should it work for my application? Here is a link:
https://www.mpja.com/prodinfo.asp?number=14592+PS
Also, does anyone see any issue with the opamp I am using? I am not sure how to read the datasheets, but the input to the opamp is only 1v, while I am powering the opamp with +/-9v (or +/-12v if I do what I want to above). Was this opamp a poor choice? I have checked the battery voltage when I hear distortion, and it is only about +/- 8.5v. Should this be expected?
I am a first time poster, and really don't know much about electronics, but I created a project for myself last year that I want to upgrade.
What I am doing is using an dual opamp (TL082 from Radio Shack) as a voltage follower in a project box in my car, between a Harman Kardon Drive+Play ipod interface, and a ground loop filter. I am doing this at someone else's suggestion because of an apparent impedance mismatch between the output of the HK unit and the GLI filter. This mismatch creates a high-pass filter, so it cuts all of the bass response out of my audio.
I am using the GLI filter because my car (a 2007 Camry Hybrid) seems to have an inherent problem with the 3.5mm aux input if ANYTHING is plugged into it, as well as being plugged into power (12v accessory power). There is an audible high pitch whine that you can hear at even low or moderate volume levels. The filter DOES remove the noise, but as I said above, the filter also removes bass.
The opamp circuit is being fed the output of the HK unit (1V max) audio signal, and I am powering the opamps with a pair of 9v batteries arranged to provide me with a +/-9 volt reference (and ground at the the zero point). I also included a 12v relay in the box to disconnect the 9v batteries when the ignition is turned off. I would like to eliminate the batteries, since I seem to get nasty distortion if the batteries are even slightly discharged.
I searched these forums and found a reference to a surplus site that has a 5v input, +/-12v output. This is compact, but I think I would need a regulator to drop the input voltage from the level of the cars accessory voltage to 5v. Is this difficult? I don't know much about regulators, but I suspect I can read up on them and figure out how to get regulated 5v from 12v.
What I am wondering about is the dc/dc converter. Should it work for my application? Here is a link:
https://www.mpja.com/prodinfo.asp?number=14592+PS
Also, does anyone see any issue with the opamp I am using? I am not sure how to read the datasheets, but the input to the opamp is only 1v, while I am powering the opamp with +/-9v (or +/-12v if I do what I want to above). Was this opamp a poor choice? I have checked the battery voltage when I hear distortion, and it is only about +/- 8.5v. Should this be expected?