[sdiy] ARP Odyssey capacitors

[Paul Perry]

My own feelings about replacing caps in old synths:

There are two reasons for replacing or substituting a component:

1. if you think the component is faulty, or likely to become so,
2. if you believe replacement will for some reason actually "improve" the
design.

In my experience, polyester or polypropylene or ceramic caps rarely fail.
So they stay there unless there is obviously something wrong & it looks as
though one is the problem.

Electrolytics can dry out & lose capacitance over the years.
I don't automatically replace electrolytic bypass caps as a general rule.
If the main power filter caps are drying out, you will know something has to
be done, because of the hum.

Tantalums are a special case.
Their design & manufacture has improved enormously over the years.
Early ones had a regrettably high failure rate. And they don't like
overvoltage at all.
So if one fails, then that's an argument to replace all.
(same as for those dodgy self-dissolving electrolytics from a few years ago,
but I havn't seen them in synths, only audiovisual gear).

As for caps going leaky - they aren't usually under much stress in a synth &
it doesn't happen a lot. It's likelier to be crud on the PCB surface itself.

Really, unless there is an actual problem, it comes down to personal
preferences. I'm very conservative & like to leave stuff alone; others are
more high energy & if they think they can replace stuff without buggering
anything else up while they are doing it, then they can go for it, I guess.

Paul perry Melbourne Australia