RE: [DML] grounding equipment to battery?

["IN2TIME" <Gary@xxxx>]

[Moderator Note: Further comments which do not discuss DIRECT APPLICATIONS IN DELOREANS will be rejected without mercy. - moderator Mike Substelny]

Just as Kayo wasn't flaming Martin, my intent is not to flame Kayo. There is
a lot of controversy over the use and misuse of stiffening capacitors. IMHO,
there are specific situations where they can be very effective.

Bass notes require power.
Loud Bass required more power.
Crisp fully-formed bass notes require instantaneous power.

If your battery voltage goes down over long periods of high demand (from the
stereo, lights, etc.), you need to upgrade the alternator, battery, or both.
A stiffening capacitor can't fix the problem.

If the battery and wiring to the amp can't supply enough instantaneous power
to the amp during the formation of bass notes, the voltage at the input to
the amp will drop and the individual bass notes can get "clipped" (not fully
formed). 

Upgrading the power wiring, using an amp with better power regulation,
connecting the amp directly to the battery, adding a stiffening capacitor,
or adding a second battery can reduce/eliminate clipping. Upgrading the
power wiring or adding a stiffening capacitor would be "easier" solutions
than installing a second battery and might be more cost-effective than a
better amp. Amps with "better" power supplies often have bigger capacitors
built in.


An alternator has very little direct impact on instantaneous clipping,
because it can't respond fast enough to instantaneous demands - in fact,
during rapid transients, it isn't even sensing the voltage at the input to
the amp. By the time it senses a voltage drop and it's output increases,
the demand is already gone. 

A stiffening capacitor is like a small, but super-fast power source (like a
rechargeable battery that can charge and discharge very quickly). If the
voltage at the input to the Amp starts to drop while a bass note is being
formed, the capacitor (located as close to the amp as possible) kicks in to
supplement the battery and keep the voltage relatively constant. As the
instantaneous power demand drops off, the stiffening capacitor charges back
up and is ready for the next high-demand bass note. Higher capacity
capacitors can handle larger and longer demands, but long low rumbling
sounds can deplete the capacitor, and at that point you are back to relying
on whatever the battery and alternator can supply.

With a stiffening capacitor, the voltage that the alternator senses remains
more constant, so the alternator is likely to be stressed even less than it
would be without a stiffening capacitor. Other than minor losses, and the
fact that the stiffening capacitor is allowing the amp to work to it's full
capacity, the stiffening capacitor does not put any extra load on the
alternator or battery.

IMHO, if your system is operating beyond the instantaneous capability of the
current electrical system, and the wiring is already sized properly, a
stiffening capacitor can be an easy, economical, and effective solution -
with no downside. Even if you are designing a system from scratch, you still
may find that you can get a little more bass out of the system by adding a
stiffening capacitor instead of upgrading the electrical system - but don't
expect miracles.

Gary
IN2TIME