Hi Neil!

> BUT, better than that, that farnell page, led me to a
> better product -- a super shallow 3-pin DIN connector.
> Mfgr data sheet is here...
>    http://www.schurterinc.com/pdf/e_d/audio_20_23.pdf
>
> Part #4850.2300 near the end of this doc.

I like that one the best so far because it's 'different from common.'
Things like the phono plug, although it is the cheapest solution, (parts
plus time,) invite people to plug the 'wrong thing' into it, like
headphones, and depending on what the box outputs might cause damage.

I'm also concerned that the phono might introduce shorting problems.
Depends on the jack design and whether it bothers the circuit.

The IC socket idea is *extremely* fragile.

But you mentioned making 'a dozen' and that brings up cost. This DIN is
probably not common and not made in very high volumes and that usually
brings the cost way up to the point that it's the most expensive part in
the box. Also need cables. Phono cables are very common and cheap and same
as the DIN connector volumes the cable might be expensive to buy, or it
brings up the cost of wiring your own. Again, at a few dozen, that's a lot
of time.

If overall cost is less of a concern then the DIN is best. If the circuit
doesn't mind shorts then the phono plug is cheaper and sturdier.

Another comment, phono plugs are tiny and that DIN plug is a monster at
*52mm*. If this is a front panel mounted thing then watch out for
clearance/interference with other controls/displays. If back panel then
obviously of far less concern.

Anecdotally, related to the 'few dozen' thing...

Part of my job as a prototyper was to break in new engineers as to 'how we
do things around here.' :) One newgineer [tm] gave me a -series- of test
fixtures to build that were ummm... 'out of the ordinary.' Not one, about
half a dozen. I asked him if he was -sure- that was what he really wanted
and described why it probably wasn't the best way to layout the panel. He
said do it. Fine. He's the engineer and I just build the stuff. A short
while after I finished them and handed them over I went visiting. He was
using them placed *BACKWARDS* on the bench, with all the legends upside
down and all the controls working upside down!!. Why? Well, it seems that
putting about a -hundred- test points (Berg strips to the logic analyzer)
at the -front- of the box wasn't such a good idea. All his other test
equipment was at the -back- of the bench. In the test fixture's 'normal'
position, with those hundred wires draped back across the fixture, it was
100% unusable and in fact the test socket was totally inaccessible. He
didn't question my layout ideas much after that, and he *never* mounted a
wired I/O point at the front of a box again. LOL!

The reason I mention that is because since this is not a one-or-two-off
thing once the design is set there's no turning back. Please think long
and hard about how the box will be used, not just about appearance. User
interface is just as important to hardware as software. If not more
important because software is easy to adjust and hardware is difficult or
impossible to change. An uncomfortable front panel is not fun.

Have a :) day!

jb

--
jim barchuk
jb@jbarchuk.com

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