[AMRadio] Speech processing technologies and methods?


Todd, KA1KAQ ka1kaq at gmail.com
Thu Dec 19 11:47:19 EST 2013


On Thu, Dec 19, 2013 at 6:26 AM, FRANK HUGHES hughes <
frsahu0003 at embarqmail.com> wrote:

>
> Hi,
> I would like to learn about the speech processor options/techniques to
> improve what I am presenting the 32V-2 input with.
> Should I start by asking Ray @ ER if he has any back-issues addressing the
> subject?
>

I would add to what Rob said here, there's really not a lot the 32V series
needs to sound decent. They sound pretty good right out of the box. Like
other rigs of the day they are somewhat restricted.

The mic you're using sounds like a dynamic, not the best mate for the 32V.
Simplest improvement you can make and IMO the best bang for your buck is to
use a plain jane D-104 with a *good* crystal element. If you want to make a
simple modification to improve the audio further, change the mic amp grid
input resistor which, IIRC, is around 1 meg. Change it to something around
5 megs or more.

Beyond that you'll be pushing the boulder uphill, a lot of work for minimal
return.

On 3885 I hear many folks discussing their signal processing methods, and
> can see that it would be fun to learn more about it.
>

Keep in mind that many of these guys are using homebrew transmitters, not
32Vs or Apaches. The biggest weakness in the 32V is the LV transformer that
gets baked by a combination of elevated line voltage and a sizzling hot 5Z4
half an inch away that will take the skin off your fingers if you grab it
before it's cooled off. It's likely not too dramatic to say that it's just
a matter of time until you fry it if you use the transmitter a lot -
especially if you started modifying and driving the snot out of it. I have
a stock 32V-2 that has only seen service as a 100 watt peanut whistle
station and it has tar seeping out of the transformer. The best thing you
can do for the transmitter is work to cool off the LV section.

But first, I have to finish my first attempt at a homebrew amp, then on to
> new technical horizons.
>

I'm with others here: if you're building an amp along the lines of 'DTC,
don't bother driving it with a 32V. Keep that as a daytime transmitter for
75/80 meters, or 40m use. Build yourself a little Class E transmitter, a
little tube exciter, or run a Flex or something along those lines with the
amp. You'll be pleased with the results and the 32V will be forever
thankful.

BTW, you probably already know that, along with your other amps, the 32V
doesn't do 160 either.

~ Todd,  KA1KAQ/4


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