Output / Input Voltage Question

I'm in the same happy boat where noon is off and 5 o'clock is LOUD. Not a big deal except the less carbon track the signal has to pass through, the better. That's why a switched resistor type is better.

Limited volume range can be awkward to fine tune. 

Beware audiophile tech talk, they will screw you up every time! Basically what happens, they will have you going round and round with a whole lot of stuff that is pretty much irrelevant. Not totally, and that is where they get you. Because every once in a while some of the stuff they talk about actually does matter. Problem is it takes you a good 10, 20 years of wasted time and effort to finally understand the vast majority of the time this stuff they go on and on about is well and truly irrelevant. Most of the time.

Like now. All that you have is an amp that does not require very much input voltage to drive it to full power. That is it. Period. Full stop. End of story. Nothing in audio matters less than where your volume knob is pointed. You get that now.

If you want you can take the time to study this stuff and when you understand it well enough then you will know ahead of time to expect the knob to be where it is. You will even be able to look at your source, be it CD or phono stage or whatever, and have a pretty good idea where the volume knob will be. It is actually pretty simple stuff once you get the hang of it.

Big picture though, keep it simple. Pay attention to speaker sensitivity. As long as that is 92dB or more you know you will always be able to find an amp to drive it nice and loud real easy without needing hundreds of watts. With turntables you want cartridge output of around .4mV or more in order to do the same, make it easy to find a phono stage. This is how to use specifications intelligently, to make your life easier not harder.
Do those two things and pretty much all the rest you can tell yourself, don’t sweat it. Eventually you may learn enough to understand why but in the meantime just tell yourself don’t sweat it.

If the volume control is too loud at a low setting you have no range to lower the volume. This guy explains volume controls and how they work!
https://www.bing.com/videos/search?q=volume+control+too+loud+on+preamp&docid=608045585391227187&...

What preamp do you have? 1.5V output from a preamp is very unusual. That's even lower than what most (if not all) digital source components provide which is around 2V for single ended outputs.