Earlier some one mentioned about building cabinets and metal parts for amps.
Some things do come easier for some than others. That's a given, but to
build an amp and do all the metal work is difficult and time consuming
unless you have the proper tools.
Lets take the tube mounting and pressurized compartment to start.
There are a lot of holes to put in the surfaces. This takes a punch or
a drill specifically sharpened to drill Aluminum without leaving a burr,
or sharp edge. Edges that need to be "broke" need an even bevel or
radius that doesn't look like it was done with a paring knife. The holes
for the tubes and sockets must not look like they were done with a hole
saw. This can be done with either a fly cutter, or punch press. Fly
cutters are used on mills which cost more than the amp. They are also
very dangerous. Punch presses take dies as well which are not cheap
and not normally made at home. Even given the proper press and punch the
hole, or holes needs to be made with out deforming the metal sheet. You
don't just put it all together and punch a good looking hole in a sheet
of Aluminum. It takes a bit of skill. To top it off, there shouldn't be
ANY scratches in the surface of the metal. Of course the dimensions must
be proper and the material sturdy enough to make for a solid
construction. Could I use the equipment to make the chassis and sub
chassis using the drills and fly cutter? Yes I can, BUT I'm not so sure
about the scratchless surface. Any scratches and I'd throw it in the
scrap bin and try again.
I dislike the fit, finish, and front panels of most amps on the market
today. To me they all should have the fit and finish like the front
panels on the Yaesu, Icom, Kenwoods, and Tokyo Hy-power equipment and
not one of them does. Nor could they afford to build those amps at a
reasonable price if they did.
Could I build a high powered amp cheaper than purchasing one? Yes I
could, but that would have to be the goal of the project. Otherwise I'm
too much of a perfectionist when building things. Most likely I'd either
never get it done, or it'd cost a fortune along with creating a very
large scrap heap.
OTOH Cabinets are fairly easy to make, if you have a good metal brake
and notcher for the inside corners along with some practice. It's those
pesky holes that are the hard part.
The panel is probably the hardest part as it includes the difficult task
of getting large and small holes in the proper position with clean
edges. Then there is the lettering which can be silk screened,
airbrushed with a template, or grooved and filled. Each takes a
particular skill and no small amount of practice. Maybe the most
difficult of all is just organizing the panel to make it look useful
without being cluttered. This is where most home brew projects really
look like they are home brew.
Study the panels of the higher grade equipment and use those as guides
as a target to shoot for in results. There's a reason they don't have a
row of meters all the way across the panel and only a part of it is to
save money. Rather than designing an amp around a tube or tubes, maybe
it'd be better to keep in mind the size of the tubes while building the
amp based on the front panel design.
73
Roger (K8RI)
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