Kinda OT, here,Ken, but, how would you compare the F500 to the TH ? I had a TH pedal for awhile and found it snarly and crunchy right from the getgo. Also, does the TH seem " louder " than the F500 ?
My primary gigging head (as has been for years) is the F500 to this day. I still love it.... loud, articulate, even, and not significant built in goosing, but not sterile either (as you know).
The TH500, as you point out, is snarly and a bit crunchy right out of the box, and has a more meaty low end (to my ear, a touch more extended in the deep bass than the F500, and a good dose of upper bass presence built in). The EQ is much more extreme/powerful/impactful on the TH500, so you can really dial in massive burp and fat punch versus the more subtle F500 EQ.
The F500 is still my personal 'state of the art' if you want a sort of 'studio mic preamp through a mixing board' sort of 'transparent' response without super bass extension or supper sizzle, or lots of midrange distortion in the upper mids or whatever.
The TH500 works REALLY well with my Audiokinesis cabs, since they are clean and even and transparent, which makes my P Bass sound a bit 'lacking in warmth and character' when using my F500 with those cabs. Nice in yang.
I don't really hear any difference in maximum volume between the two... they both seem honestly rated. Both loud, and both do EXACTLY what their designers set out to do. With Markbass, the F500 is 'a smaller LMIII that is a bit crisper, tighter, punchier, louder and 'quicker feeling'. With the Aguilar, the TH500 (IMO) is about as close as one can get to a DB751 in a lightweight amp.
I liked the F500 with the Baer ML112, but liked the LMIII better... warmer and more organic... better match with the mid driver voicing IMO.