Building a power supply for an Exposure VII pre-amp
This power supply is basically a version of 'FinestCap' but with the brilliant Teddy Pardo VBE mods.
It's designed to power my brother's Exposure VII dual pre-amp so, in addition to the +ve rails, it also needs two -ve 24V rails.
It also means a bigger case is required to fit in all the components. An old Naim 250 sleeve from ebay provided a suitably posh housing so all I needed to do was build the chassis.
In time honoured fashion (i.e. as per all my previous case-builds, skip-dives excepted) the chassis is fabricated from two pieces of aluminium angle (3" x 3" x 1/8") joined by a flat aluminium sheet (12swg or 2.5mm). This makes for a pretty strong 'U' construction and saves trying (and failing!) to make neat bends in a single sheet of aluminium...
In time honoured fashion (i.e. as per all my previous case-builds, skip-dives excepted) the chassis is fabricated from two pieces of aluminium angle (3" x 3" x 1/8") joined by a flat aluminium sheet (12swg or 2.5mm). This makes for a pretty strong 'U' construction and saves trying (and failing!) to make neat bends in a single sheet of aluminium...
This miniature 'saw-table' looks a bit 'noddy' but it's actually really useful and saves an awful lot of time and effort when cutting out holes, etc. In addition, each piece of angle needed triming-down along the entire length so it would fit inside the Naim sleeve - try doing that with a hacksaw!
And there are a fair number of holes and brackets to cut/make. The transformers - two of Les Wolstenholme's special laminated transformers are actually a bit too tall and although they'll just slide into the Naim sleeve there isn't any room left for the the thickness of the chassis. The work-round is to have the trannys poking through a cut-out within the chassis base:
