I've wondered about this in the past too.
Using "hand-built" mixers seems to be a part of the TT design style
and has been for years.
I would have though production costs would have swamped the component
cost when you include adjusting the balance. How much do those little
trifilar binocular core transformers cost to make? Or perhaps I'm off
base and with large purchases they're saving several dollars per
radio in mixers.
Given the JFETs set the limit the high level mixer would be a bit of
a waste to use a high-level mixer (plus an extra driver stage would
be needed) but a TUF-1 or TUF-3 would just drop in or SBL-1 would
drop in and retain the balance adjust.
Does the Jupiter just have a single pair of JFETs in the front end
like the 320? Or do they parallel the J310s?
On Oct 3, 2007, at 9:30 AM, Dr. Gerald N. Johnson wrote:
> I'd rather see them spend $3.95 on a packaged mixer made by an
> expert in
> mixer making than spend 2 cents on slightly slow diodes and 23 cents
> each on almost good enough transformers. I think the receiver
> performance would be detectably better with the packaged mixer, like a
> MCL TUF-1H... though the H suffix may cost a little more than
> $3.95, its
> not much.
>
> 73, Jerry, K0CQ
--
Kevin Purcell
kevinpurcell@pobox.com
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