Adding Subwoofer output to Sonic T-Amp

[HolyGhostFire20]

I am currently using the sonic impact's volume pot in shunt mode using 10k resistors wired directly to the audio board using 2.2uf capacitors. I wish to add a subwoofer output using the same pot. Can I use the same wires going to the audio board for the subwoofer output or will that not work? What is the best solution in using the same pot? Thanks for your time in this manner, Kevin.

 

[Pano]

It will work if jump off the output of the volume pot. It just won't work well.

You're much better off to use a buffer for the sub out. Any good dual opamp would do.

 

[DcibeL]

Wiring the subwoofer output as a shunt from the input to the T-amp will work, but will increase the load that the source will see, and possibly have adverse affects to the sound quality.

Yes, a simple buffer will work, but unless you want to build an entire new power supply (might as well build an entire pre-amp if you want to do this), you will have to use the op-amp with the single 12V supply for the T-amp. This requires a coupling cap on the output of the op-amp, and possible coupling caps on the input, and from the inverting input of the op-amp to ground. I am sure if you look around you will find the information on using op-amps with single supply, or if you come up empty, I can look up the calculations for you.

 

[Pano]

Single rail is the way to go. Just use big film caps on the output. Nothing exotic needed, just good quality. Be sure to filter the 12V near the opamp.

You can use a virtual ground scheme for the opamp and not need output caps. But then grounding inside the amp becomes a nightmare.

 

[frasco]

I was just thinking about something similar and found this:

Would this work? Is there a simpler method (with less components)?