[Amps] Building an Amp 101

[N1BUG]

On 01/18/2014 03:16 PM, Roger (K8RI) wrote:
> There is actually a preferred length, width, and height ratio that can
> easily be maintained.

I presume this refers to desktop amps. My early ones were, but 
everything today has to be rack mount. No space, so everything must 
go vertical.

> If you are willing to take the time to learn to use the hand tools
> properly, you can build as good a looking amp as the commercial.

This seems to assume the use of new material or at least material in 
good condition. Often what I can get is previously used with holes, 
or scraps that are deeply scratched, dinged, bent, too small and 
must be spliced together... etc. I've become very good at altering 
the layout to hide defects, but ultimately one only has so much 
leeway. When defects in materials can't be hidden, I lose the 
incentive to do my very best work. I suppose that's a personal flaw.

> Copy
> the physical layout of some of the amps with better reputations.  You
> can design the circuit if you want to, but why "reinvent the wheel" so
> to speak when it comes to the cabinet and physical layout.

Wow! If I had to limit myself to using only parts that will fit the 
physical layout of commercial amps, I probably wouldn't have any 
amps. I'm able to build amps because I am willing to use parts no 
one else wants. Often they are big, ugly, or both. But they work fine.

> BTW you can
> purchase the chemicals to alodyne (put that gold color and protective
> layer) on the Aluminum chassis for a reasonable price from Aircraft Spruce.	

Interesting. I didn't see them on a quick search, probably because I 
didn't know exactly what to look for. But I will do some research 
and check that out.

> BTW use a harder alloy than the typical soft aluminum we usually see in
> home brew.  It's stronger and easier to work with.  I use 6061-T6 but
> there are better and cheaper alloys available.  Ask the supplier for
> suggestions. They are often quite willing to help pick the proper
> material..

Supplier? I use whatever I can scrounge. Mostly 6061-T6 or similar, 
but sometimes I score something better. I prefer the harder alloys. 
I find them easier to work with and the end result is better.

> If you have the patience to build those with simple hand tools, you have
> the patience to learn how to use those tools to their limits.

My earlier wording was probably misleading. In those few instances 
where I have materials and parts that are capable of looking good, I 
can turn out a good looking product.

One of my fondest dreams is to someday rebuild my 4CX1500B HF amp 
into a form that looks nice. The original doesn't because the only 
enclosure available was too small and forced a cramped layout. 
Meters don't match, controls are crammed too close to meters, etc. 
The same could be said for my 6 meter amp. I've looked into a 
rebuild several times but the cost of material and a few parts would 
be far more than the total cost of the amp the first time around. 
Now I remember why I built it the way I did.

73,
Paul N1BUG