[Boatanchors] difference bet. 75A3 and A4?

[Todd, KA1KAQ]

On 10/19/05, Eugene Hertz <ehertz at tcaf.org> wrote:
> Can anyone give me a brief comparison of the collins 75A3 and A4 receivers? I've been *toying* with the idea of getting a ham only receiver as opposed to my sp600.  I tried to find some info on the internet, best I found was that the A4 had better audio response.  Are the vastly different or moderately different? Frankly, I prefer the look of the A3 in the more traditional chassis/cabinet look but if the A4 is vastly superior I could be convinced.
>
> I understand that the mechanical filters in both allow some kind of ssb reception (2.8k? 3.1k?) but I have also heard that a product detector is even better and would be desirable for either the 3 or 4.

Eugene -

Let's see if this one makes it to the list, my last post about Beckman
was bounced back.

The mechanical filters actually work only to narrow things in noisey
conditions. The 75A-4 actually has a product detector for SSB
reception. While the A-2 and A-3 are basically identical (except the
A-3 having 2 mechanical filters which could be retrofit to the A-2),
the A-4 is a 'new' receiver in comparison. The main difference is that
the 75A-4 was designed for SSB operation with the associated
refinements. Even the cabinet design is completely different, with the
A-4 cabinet being made up of several pieces including the front panel.

If you want a more traditional AM/CW receiver, stick with the A-3 or
even get the A-2 and avoid the mechanical filters altogether. If you
want the SSB option along with reasonably decent AM and CW with the
ability to narrow things down to 500cps (with CW filter), the 75A-4 is
tough to beat. And although 6kcs was the best you could do for AM,
there is now an aftermarket filter available for 9kcs to broaden
things out a bit more. You can tune SSB with the A-3, but not as
easily. And there's also the passband tuning system on the A-4, which
is very ingenious and fun to play with.

As far as price, a 75A-4 will set you back at least twice as much as
the earlier models if you shop online, depending on condition and
optional filters installed.

My choice would be for the 75A-1 with its nifty band-in-use lighted
dial and very good audio. Tunes SSB amazing well too even though it
has no prod det. Doesn't cover 160, though.

de Todd/'Boomer'  KA1KAQ