Some dirt pedals do not work properly with a buffered input signal. For example, I have two analog "amp-in-a-box" style distortion pedals (ZVex Distortron, Wampler Plexi Drive Mini) that either hum or hiss loudly when processing a buffered signal such as:
1) the bypassed output of the HX One when the Bypass Type parameter is set to "DSP Bypass" mode, and
2) from what I can tell, the effected output of the HX One (regardless of the Bypass Type setting).
I have only tested a few pedals, but for the record, the Fulltone OCD and the JHS Screamer seem to play nicely after the HX One pedal.
I have a few other pedals that include a buffer, some of which can be disabled via an internal DIP switch. The nature of the noisy interference differs depends on the type of buffer circuit used in any given pedal. Diagnosing these issues takes a lot of trial and error. I had to test a simplified signal chain (guitar -> HX One -> dirt pedal -> amp) to figure out the source of the interference.
So far, I am really happy with the HX One either at the end of my signal chain in front of the amp or next to the other digital time-modulating reverb and delay pedals in my effects loop.
