The ZX-HD has succesfully been tested with:
- ZX Spectrum 16K, 48K, 48K+, 128K, +2, +2A, +2B, +3, Harlequin clone
- Interface 1 and Microdrive (ZX-HD can be in between or behind the Interface 1)
- DivMMC EnJOY!
- DivMMC EnJOY! *mini*
- Kempston Joystick interface
- K-Mouse Turbo
- Interface 2
However it’s important to consider the power usage on the 5V supplied by the ZX Spectrum, as the voltage regulator inside the ZX Spectrum has a limited maximum current.
You will find measurements on this page (click).