Whoops said:Thanks you so much Ian.
So in this application is there any reason to use an expensive 600ohm T PAD over the 1K pot or practically they will both achieve the exactly same results?
All a 600 ohm T pad will do for you is ensure the load on the transformer stays close to 600 ohms no matter what its setting. A 1K pot connected to a 10K bridging input will load the transformer with 909ohms when fully up and 1K when fully down. Most preamp's distortion will be load dependent so there may some small benefit in making the 1K pot look closer to a 600 ohm load. You can do this by adding a 1K8 resistor across the ends of the pot. Other than that the expensive T-pad has nothing going for it.