I have a line of attenuators that work exceptionally well with either tube or solid state amplifiers that are ridiculously inexpensive.
The input impedance remains relatively constant throughout the volume range on the input, making the source completely burden free. The input impedance is 100K and this is a completely resistive load. There is nothing within my attenuators which can add or modify the incoming audio from a source. By default, they are 100% noise-free as well.
Applications? Amplifiers, either tube or solid-state with high gain inputs. If you have sensitive speakers and an amp with a "hot" input, one of our passives will be a fantastic upgrade. So far there have been no unsatisfied customers and no synergy issues. One of my customers has ordered THREE of them! They are inexpensive, but work well beyond their price point. All wiring is still point to point, even at the starting price of $75.00 for a single input passive. Add $25.00 for a dual input. More inputs are available. You will have a choice of a toggle or rocker switch for the inputs on the two input model. Three or more inputs use a rotary switch. You may also select a knob type.
These are also great as a means of getting more range out of your present preamp's volume control if you do not have enough range and for precisely quieting down high output sources.