@fullers If you are also considering preamps that have no sound to them, the Topping pre90 ($600) sounds like the Benchmark LA4 ($2600). Both are like wore with gain and do not seem to add to the sound. They measure the same and sound the same. However, the LA4 works great with every amp I had while the pre90 has only worked properly (the volume) with my Benchmark AHB2 amp and Parsound A21+ amp. Not so with a CODA #8 or a few Class D amps I have now sold.
There are a few people on ASR website using the pre90 as their preamp, such as a Stereophile reviewer. He dumped his Benchmarlk LA4 for the pre90. I plan on dumping my pre90 and keeping my LA4.
This is just a very low cost suggestion to get a reference level nuetral sounding preamp. If you want warmth then these 2 preamps are not the correct choices.