Originally Posted by Bigredlid
i think my tube is a TA850C or something like that
Welcome to the Bazooka Forum BRL. Yes, there is a FAST Harness that you can use, even if you have the Infinity System. You can use FAST-9999 (universal harness) and be sure to purchase the FAST-BTAH extension harness for your TA850C.
The FAST 9999 is extremely easy to install, just be sure to tap into the correct wires in your factory harness. Using the FAST-9999, you will simply tap into your factory 12v power with the Red Wire, factory 12v key-on/key-off with the Blue/White Wire, and the others in the like manner. Don't forget, you can also configure the Tube for Auto-Turn On as well, if you are unable to find a key-on/key-off 12v (and in doing so you will not need to use the Blue/White wire in the FAST-9999.) Also, tap into the front speakers for the Tube's signal. This will allow you to adjust the fader if needed, and not decrease the signal going to the Tube. Often, when people are trying to adjust for the imaging, they will decrease the signal going to the rear speakers via the fader. In doing so, the signal to the rear speakers is decreased in correlation with the volume. Using the front speakers as your High Level Input source you will be able to use your fader and not decrease the volume of the Tube
Blue/White: remote turn on
Left Front (-): White/Black
Left Front (+): White
Right Front (-): Gray/Black
Right Front (+): Gray
Please post back with anymore questions you may have.