Hi Georgemg,
I have been using a Supratek Chardonnay for two years. It is a very versatile preamp in a sense that you can tailor its sound to suit your taste, by tube rolling. It never failed to amaze me what it is capable of in regard of sound reproduction. The baseline is : it is very musical but not without the details that loved by audiophiles. All dependent on your other equipment and the tubes you used. I have a brief audition of the Melody 1688II in the Hong Kong showroom. It was partnered with Zu droid speakers and a tube power amp (I forgot the brand and model). It was too mellow for my taste in that setting. The piano was bloated with lost of attack. Voices were sweet but big.
I have no experience with the Wytech, perhaps someone else can help.
Preamps that I owned previously : ARC SP9, LS1, LS2, CAT signiture, Matisse reference, Marantz 7 (remake) and Nagra PLP (which I am still owning), but I enjoy the Supratek most.
Hope that is helpful
Regards,
ywLee