[sdiy] Group buys: Alpha-style, dual pots, and Joysticks (WAS: RE: Dual-gang reverse-log pot group buy ?)

[David G. Dixon]

flightofharmony asked:

>> I don't know - what markings do they have on the case? <<

They have no markings on the metal canister (which is a gold color), and
"B100K" in white letters on the top front of the plastic pc-board part of
the pot.  (I only have B100K versions of this particular pot.)  I have a
feeling that they are the same pots that Futurlek sells (they look exactly
the same based on the pictures of the latter I've seen on the web).

The problem with them is that they do not appear to admit desoldering and
reuse, and I'm not really even sure that they work terribly well the first
time.  It would seem that the resistive strip becomes disconnected from the
riveted metal pins after soldering.  Perhaps some of the plastic from the
pc-board part of the pot is getting between the two and breaking the contact
(some of the plastic seems to "boil" if the soldering iron is held on the
lug long enough to flow the solder joint -- these are all pc-mount pots, by
the way, including the Alphas).  If I pull on the wires, I can sometimes
reestablish the connection.  For example, if this pot is a frequency knob on
a VCO, then pulling on the wires causes the frequency to go sharply up or
down as the contact is reestablished and rebroken.  Sometimes, just jiggling
the wires causes the same effect.

At least 33% of these pots failed to work after rewiring a panel.  However,
none of the Alpha pots I used (all the non-B100K pots on the panel, as it
happens) failed to work upon reuse.  I'm sold on Alpha pots, and every
synth-diy'er I know swears by them, so they seem like a very safe buy.  I
would say that it's definitely worth an extra dime or two per pot to get
reliable performance and avoid having to redo panels!