anatomy of a digital stompbox?

[mahler007]

Hi Slutz,
Wondering if anybody can help me out with this question...

With digital stomp boxes (like a Boss Digital Delay or Reverb, or a Line 6 DL-4 or what-have-you), how is the processing applied?

Does the analog signal go in, get entirely converted to digital, processed, and then re-converted to anaolg before being spit out?

OR

Does the original analog signal get passed through untouched, while the effect is created by "sampling" (or perhaps use some other appropriate word here that I don't know) the analog signal digitally, processing it, and then combining (or mixing) it with the original analog signal at the output?

Just curious, as I'm experimenting with working with stompboxes as effects OTB, but would like to avoid using even more D-A/A-D conversions in the process...

Best to all,
Andrew

[Brightbird]

It depends on the box. I know some rack mount units use an analog output mixer for mixing the dry (analog input) with the processed stuff. Others digitize the input and deal with all the mixing in the digital realm.

For the stomp box type effects, I would think everything gets digitized, but the only way to be sure is to look at a schematic.

[Tibbon]

Keep in mind, that blending a digital signal back with a straight analog signal is going to have some comb filtering from the delay induced by the A/D -> processing -> D/A.