According to the Guitar Geek rig, which is based on a interview with Shields in 1991, he used a Shredmaster. However, these rig diagrams seem to be notoriously unreliable.
According to a 'Guitar Player' magazine article (May 1992), he used a Shredmaster - although some consider that to be a misidentification by the writer.
According to Shields' ex guitar tech, in a quote much cited on forums, he is emphatic that Shields used a Guv'nor:
It could be, of course, that he used a Guvnor and a Shredmaster at different times."Kevin never used a Shredmaster pedal (he did, however, use 2 Marshall Guv'nor pedals during the Isn't Anything live shows)". "For Loveless live shows he used...Marshall Guv'nor.."
Below is a photo of Shields' pedal chain from a Loveless era gig, c. 1992:
To zoom in, see this link.
The Marshall pedal in the above photo is about half way down the pedal chain, located immediately between a blue Digitech PDS series sampler (below it) and a light coloured Boss pedal (above it).
On another forum the black Marshall pedal in the photo above has been identified as a Guv'nor without question. However, to my eyes, the side profile seen of this pedal in the photo above looks far more like the Marshall Shredmaster (or the Drivemaster or Bluesbreaker) than the original (black) Marshal Guv'nor which had a different shaped enclosure.
The following photos provide a good illustrtaive comparison of the contemporary Guv'nor and Shredmaster pedals.
Also see this photo
So what do people think?
In the photo at the top of this thread showing Sheilds' pedals on stage, is that a Guv'nor or a Shredmaster?