For any system, new or Vintage, without Remote Volume Control, I often and highly recommend this Chase RLC-1 Remote Line Controller
This one is ridiculously over-priced, but it shows it well
Noiseless! It's claim S/N ratio 105db is true, I have used them in or out, thru tape loops, none of my friends can ever detect any difference except the advantages of it's features.
You MUST have the Remote, no controls on the unit. They pop up for sale frequently, if you see a used one with remote at a good price, or, a new one under $200. jump on it.
One way is to find and buy a remote separately, now you can buy a unit missing the remote.
It has Remote Balance, once you have that feature, you won't want to live without it.