It depends on which type of Dumble you're searching for. As other people already said, every single D is different from another.
Said this we can also add that, at least, we could divide the "D" sound in two big circuits: Overdrive Special (ODS, two channel, Robben Ford has two of this type) and Steel String Singer (SSS, one super pristine-infinite-sustain channel, 150w, used for example by SRV).
I don't like so much Bruno Super 50/100, but I never played one of them, just listened on YT. I got various clone or amps inspired by "D" such as Fuchs Ods, Skrydstrup Od50 and a couple of Italian Graaled head, made by Tony Dangelo.
If today I have to choose to take with me a single "D" amp on a desert island, I will take as ODS type a Quinn TKT183 for sure and as SSS type one between these:
-Bludotone Hi Plain Drifter
-Welagen SSS
-Two Rock Silver Sterling Signature
It would be amazing if Cliff could add a SSS type to the long list of Fractal Amps.
Please Cliff!