Many years ago I compared the Counterpoint SA-5000 (similar to the SA-5.1) to the 3A and Quicksilver preamp ( I think it sold for $700 or $1000). The stock SA-5000 bettered the 3A by some and both were much better than the cheap QS preamp. The Counterpoint preamps can be modified to sound much better than the stock versions by the suggested direct modification. After that, you can take them to higher levels with the line stage and power supply modifications. I actually prefer the SA-2000 and 3000 once I modify them with tube regulation. It makes them more musical, and quieter.
Happy Listening.
Happy Listening.