Admittedly I have not heard the Manley preamp but I have owned a couple Shindo pres and heard others. The Shindo sound is very distinctive (and very pleasant for most, although if there were to be a criticism it would not be inaccurate to say they are not neutral).
"The 300b preamp uses obviously 300b tubes which gives the preamp a very dimensional and very flowing organic presentation which is the Shindo sound..."
Your argument here is the Manley should sound like a Shindo pre because it uses a 300B DHT? Not a single Shindo preamp uses 300B or any other DHT, as a matter of fact. In fact he is quite unconventional in using (IDH) pentode and tetrode signal & power tubes in preamps. Furthermore, despite using very different tubes (and, I think, circuits) his preamps from the bottom of the line to the top share that very distinctive sound.
The OP asked specifically about Shindo preamps. It is not too relevant to bring up the Manley unless you have listened to it back-to-back with the Shindo Monbrison in the same system and found it to sound very similar. If that is the case, I apologize.
OP, even though an English gentleman with the initials TE has stolen my heart I rather wish I'd held on to my Shindo Monbrison. It is really an incredible piece. However, if you don't do vinyl you're spending a lot of money on circuitry you'll never listen to. In that case if it were me I'd go for the Aurieges-L even though there's no doubt the Monbrison's line stage is superior.
As for describing the sound, the Jack Roberts reviews do a pretty good job.
