[Amps] Why people don't build amps.

[Cecil Acuff]

----- Original Message ----- 
From: "Roger" <sub1 at rogerhalstead.com>
Cc: <amps at contesting.com>
Sent: Thursday, March 25, 2010 2:56 PM
Subject: [Amps] Why people don't build amps.


> What are the sources for inexpensive transformers that will
> do the job?  Not microwave ovens, those things get hot and are not
> designed for continuous operation. OTOH if one is willing to put up with
> their short comings they can be paralleled to provide power for a medium
> size amp.
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Interesting post...I have some of the same questions.  Options for 
inexpensive, reasonably sized plate transformers?

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> But lets say you have access to one of those ultra linear 3CX or
> 3CPX5000 pulls with fantastic IM in the minus 50 db range,  that can
> comfortably run the legal limit using all of the drive from your 100
> watt exciter.
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Can someone provide sourcing info on reliable, reasonably priced pulls for 
home builders to build with?
Would love to buy a couple Triodes that don't require sockets.  Would even 
consider tetrodes.

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> Winding the tank coils is easy, but may require sacrificing some copper
> tubing while learning, or you can find some one who is good at winding
> coils.  Given the plate impedance, you should be able to find a design
> to copy which makes placing the taps on the coils much easier.  Also
> good hefty toroids for the 160 and 75 meter bands is now the way to go.

---------------------------

I would be more interested in learning how to properly wind, measure and tap 
using my GDO than shotgunning it.   I have used the copy cat method and it 
works fairly well but I desire to understand.
Are there books that describe the process for those of us who are technical 
but not engineers?

What about no band switch and no tapped tank....just a large edge wound 
roller inductor?  Maybe a good bit more expensive but time and loss of 
materials to trial and error are expensive too.

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> Now lets go back to that legal limit issue. I'm not condoning illegal
> actions, but what is really more ethical, running a 2 or 3 KW amp with a
> very clean signal,

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I'd much prefer to build and operate an amp capable of 2500W ICS at the 
legal limit and not worry about splatter and stressing expensive components. 
(or duty cycle)

Post raises several good questions for those of us that want to homebuild 
but seem to have more questions about doing it right than answers.

I have been inspired by the posts of the last several weeks...to the point 
where I started looking for suitable cabinetry for building.  Purchased two 
19" rack mounted chassis that had contained 900Mhz radio transceiver systems 
from work.  Should make excellent cabinets for home amp projects.  All 
aluminum, probably 18" tall and 24" deep.  Will require some work to add and 
remove some internal compartments but good starts for $25.00.

Cecil
K5DL