JM, thanks for taking the time and trouble to post this information, it is really very helpful to me. It's great to have real data. Do you know for sure that this material used by Marshall is Sil-Pad?
From a manufacturing perspective, I would guess that using a rubberized product vs mica/lube was as much ease and convenience as cost. From reading the Berguist site, that appears to have been the motivation for inventing the product. In my case however it's moot since I haven't found a source for the original material. Marshall referred me to US Music Corp. for parts, but they say that they're transitioning as the US parts supplier from Korg, and the transition is happening over the next few months.
Also, the MOSFETS I'm replacing use a TO-3P package, which looks like a TO-220 but is a bit larger. It looks nothing like a TO-3. I ordered an assortment of mica insulators yesterday from Mouser, but they didn't carry one for a TO-3P. I could either go with a TO-220 mica and have some overhang, or use another size that may be large enough but have a cutout or two in the wrong place. Any suggestions on that front?
From a manufacturing perspective, I would guess that using a rubberized product vs mica/lube was as much ease and convenience as cost. From reading the Berguist site, that appears to have been the motivation for inventing the product. In my case however it's moot since I haven't found a source for the original material. Marshall referred me to US Music Corp. for parts, but they say that they're transitioning as the US parts supplier from Korg, and the transition is happening over the next few months.
Also, the MOSFETS I'm replacing use a TO-3P package, which looks like a TO-220 but is a bit larger. It looks nothing like a TO-3. I ordered an assortment of mica insulators yesterday from Mouser, but they didn't carry one for a TO-3P. I could either go with a TO-220 mica and have some overhang, or use another size that may be large enough but have a cutout or two in the wrong place. Any suggestions on that front?