what about Tantalum capacitors

[smackoj]

amigos; could someone shed some light on the Tantalum caps?  Are they all polarized and needing to be oriented correctly in circuits? do they sound 'better' in stomp box circuits or SS amps in general? 

 

[HotBluePlates]

I don't know much about tantalum caps. So here is a bit I copied from wikipedia:

"A tantalum capacitor is a type of electrolytic capacitor ... The tantalum capacitor distinguishes itself from other capacitors in having high capacitance per volume and weight [HBP: notably higher than aluminum electrolytic caps]. Tantalum capacitors have lower equivalent series resistance (ESR), lower leakage, and higher operating temperature than other electrolytic capacitors, although other types of capacitors are even better in these regards. Tantalum capacitors are considerably more expensive than any other commonly used type of capacitor, so they are used only in applications where the small size or better performance are important."

I have only seen varieties which were polarized; I assume they all are given the above says this is an electrolytic-type cap (that's new info to me).

I would look at the above and say the pros/cons of tantalum are:
Pro - lower ESR, lower leakage, smaller size for a given capacitance.
Cons - High cost.

I can't comment on tone differences; some here have tried them as cathode bypasses in tube amps and liked the sound better than an aluminum electrolytic. I personally haven't found a reason to even try them yet (although yes, they are in a number of stompboxes).

[John]

I believe they are supposed to last much, much longer than 'lytics, is that really true?

[smackoj]

hi and thanks mucho amigos. I found this explanation in a course offered by Penn Foster College. here is their section on Tantalum Caps:

Tantalum Capacitors
In a tantalum capacitor, tantalum pentoxide is used for the dielectric.
Tantalum capacitors are available in three forms: foil, wet electrolyte,
and solid electrolyte.
A foil tantalum capacitor is made of two layers of tantalum foil. One of
the foil layers is oxidized to produce a thin deposit of tantalum pentoxide
on its surface. The tantalum pentoxide acts as the dielectric.
The entire assembly is rolled and sealed in an aluminum case to complete
the capacitor. The typical capacitance range for foil tantalum capacitors
is between 0.5 F to 2,500 F, with voltage ratings of up to
630 VDC.
A wet electrolyte tantalum capacitor is made from pellets of tantalum
powder with a wire lead attached. The pellets are then purified and
welded into a porous mass. A thin layer of tantalum pentoxide is
formed on the surface of the pellets by passing a current of electricity
through the pellets. Finally, the entire assembly is sealed in a tantalum
or silver can containing an electrolyte solution. Wet electrolyte
tantalum capacitors are available in capacitance ranges from 0.1 F
to 2,200 F. Working voltages range from 3 VDC to 150 VDC.
A solid electrolyte tantalum capacitor is constructed much like the wet
electrolyte version. The pellets of tantalum are coated with dry
graphite, manganese dioxide, and silver powders. This assembly is
then sealed in a metal can or dipped in plastic resins to complete
the capacitor.
The solid electrolyte form of tantalum capacitor is available in capacitance
ranges of 0.005 F to 1,000 F. Working voltages are in the
range of 3 VDC to 125 VDC.
All types of tantalum capacitors offer the advantage of capacitance
stability. Also, tantalum capacitors are up to three times smaller than
many conventional electrolytic capacitors. A tantalum capacitor
can be made so small that it can be used as an IC chip capacitor or a
surface-mount capacitor. This type of capacitor is used on standard
and miniature electronic circuit boards.
Cheers