Audio Research SP16 annoying volume control

I had similar issues with my ARC LS-15.
I swithced to LS-25 that has more volume steps and it helped, but the solution was delivered by adjustable gain of LS-25. I used it only on lower gain setting. That really helps. That's why I suggested lowering the output gain of your SP-16. Or get another preamp. One of the best volume controls I've seen on a preamp is on Sonic Frontiers. You really can not ask for a finer adjustment. I think it has 180 steps or close to that number anyway. You can fine tune that volume control. It's really nice.

The problem you identify is one I also experienced, mostly because I am using high efficiency speakers. There simply was not enough flexibility when listening to high output sources (i.e. CD's) at low volume levels. The good news is that it is an easy problem to solve. Send your unit back to ARC and have them do their "gain modification" which simply involves dropping a high quality resistor in whichever source you would like to shelve down the preamp output. I only did the CD input so the mod was called the "CD only gain modification". Now I have much more flexibility when setting the volume during CD playback, particularly at low listening levels. A secondary effect is that the volume is now matched for CD and LP playback. It cost around $60 if I remember correctly and they did a thorough check up on the whole unit while it was there.

My dad had the 16 then jumped a few steps and bought the Ref3, with efficient speakers it was an issue but was tamed by attenuators that shaved 9db off signal, some are a sonic compromise and some get pricey but have little to no negative affect..........Rothwell makes a model some like and some avoid but they are not pricey to try.
PS The Ref3 has a volume NOTHING like the 16,,,,,,,for $10K it better not!

Mating a preamp with an amp, you need to consider several things, such as gain of preamp, gain of amp, amp sensitivity, preamp output impedance, amp input impedance.

What Audiophile have said is very true (maybe with the exception of in/out impedances). I would also throw in a mix sensitivity of your speakers and output voltage of your CD player (I had this problem several years ago when I was using Theta Gen Va which had a generous, 6V output voltage).

To remedy the situation, you can (in general) do one of the following:

1. Reduce the output voltage of your CDP
2. Reduce gain of your preamp
3. Reduce gain of your amp
4. Reduce the sensitivity of your speakers

Reducing gain of your preamp seems to be the easiest thing to do (for example reducing sensitivity of your speakers would basicly mean that you would have to buy different speakers).

So if I match the pre-amp to a ARC power, then I presume that this would fix the problem?