Lowther refurbishment notes

External terminal replacement

The original paxolin-mounted external terminals were in relatively poor condition, so I replaced them with pairs of Monacor BP-420 terminals. Since these are mounted fitting each one in a 7.2 mm hole, I needed to block the holes they formerly occupied, I first used scrap wood to partly fill the holes, with rapid-setting (5 minute) epoxy, thickened with around 30% by volume of micro-balloons[1]. This mixture has a similar consistency to silicone filler or soft putty. It is easy to use as a gap filler, sets a bit faster than straight epoxy and, when set, sands easily.

  1. micro-balloons are tiny, lightweight hollow glass spheres that look similar to coarse flour or plaster of paris but are much lighter.
    Most fibreglass or epoxy suppliers sell them.

External terminal protection

The Monacor BP-420 terminals I fitted to the enclosures are quite bulky, as shown by this dimensioned drawing:

Hand-drawn illustration

Because of this bulk, I also glued and screwed strakes, made from three 20x20mm softwood strips glued together side by side, that extend across the full width of each enclosure's rear surface. The ends and horizontal edges are bevelled to minimise harm to other furniture. One end of the middle 20x20mm wood strip was left short so that the BP-420 terminals are partially enclosed by the two side strips and, since the terminals are only 19mm high, they don't project above the strakes. See pictures of the enclosures for more detail.

The terminals must be mounted by drilling 7.3mm holes in the enclosure's rear surface. These should be 165mm above the external base of the enclosure with the terminal nearest the side of the enclosure set 35mm in from the enclosure's external corner and the other one 25mm further in.

I calculated the vertical terminal position as the sum of:

I calculated the horizontal terminal positions as:

Internal wiring

I replaced the enclosure's internal wiring because I wasn't sure that the original wiring would be long enough after I'd repositioned the enclosure's external terminals. B&Q sells reasonable quality copper audio cable in sensible short lengths, so I used that. The points to note are that: