Yes, that is one option…it is part of the nature of recording using analog tape, and the 1/2” 8-track format is not free from this nature…more susceptible than some other formats depending on the machine.
Noise is noise. On a tape machine it is the product of the base noise floor of the power supply and electronics in the signal path, as well as the tape noise itself which is largely a product of the mechanical activity of the tape gliding across the heads. In a “vintage” machine like the 48, if it’s not been addressed, often times a recap of the power supply might lower the noise stemming from the electronics a measurable amount (but not substantially compared to the innate tape noise). Otherwise the noise is the noise. But there are a couple ways to address it; to improve dynamic range.
Dynamic range is the amount of sound level difference between the noise floor, and at the other end your signal. If the dynamic range is relatively small, then the noise can be more frequently heard amidst your program signal. We perceive this as the noise being “louder.” The other way to think of it is the dynamic range is too small. So how do we increase the dynamic range? Either make your program signal louder on tape (which can also be perceived as your noise being quieter), or employ processing that reduces the noise (noise reduction)…or do some of both, though there are limits to this because making your signal too hot on tape can mess with some noise reduction processing causing unwanted artifacts.
Making the signal on tape “louder” is easy…just record hotter. And if recording hotter is undesirably saturating (distorting) your tape, then get tape that can handle hotter signals before saturating than your SM911, like SM900 for instance. But understand that will require re-biasing and ideally recalibrating the machine. And also be aware if getting tape that can handle hotter signal before saturating, and printing “louder”, is still not bringing satisfactory results as far as improvements in dynamic range, and you reach a point you are driving things so hard you are clipping the signal electronics, then your only solution is either tone down how hot you are printing to tape and bring noise reduction processing into the picture, or…get a tape machine with more robust signal electronics that have higher headroom…can drive signal to higher levels than the 48 before clipping.
Welcome to tape.
Let me know what questions you have.