tre, I am getting a bit confused here. I gather now that your cartridge drives a Chinook which in turn drives a Bryston linestage with an additional 15db of gain after the phono gain. You've got gain to spare, even if your Chinook itself only supplies 60db max. I am using the Steelhead as a full function preamplifier, so that the total phono gain in my system is whatever I set on the Steelhead. At the max of 65db, I have ample gain with the AT ART7. You've got 10db more gain than I do at your disposal. Of course, keep in mind that the input sensitivity of your amplifiers and the efficiency of your speakers also play a vital role in determining how much gain you need.
Now for my area of confusion: Did you say that you are using the balanced inputs on your Bryston? But the Chinook is single-ended, so how does that help, unless the Bryston has a circuit or a transformer at its line input that converts the SE to balanced? If the system were true balanced, using the balanced mode will result in less noise, not more noise. But as it is, I don't know if you'll have any benefit from the balanced inputs.
Now for my area of confusion: Did you say that you are using the balanced inputs on your Bryston? But the Chinook is single-ended, so how does that help, unless the Bryston has a circuit or a transformer at its line input that converts the SE to balanced? If the system were true balanced, using the balanced mode will result in less noise, not more noise. But as it is, I don't know if you'll have any benefit from the balanced inputs.