FW: [sdiy] Tantalums in Yamaha CS20M/CS40M

[Jerry Gray-Eskue]

Opps I meant to sent this to the list..

-----Original Message-----
From: Jerry Gray-Eskue [mailto:jerryge at cableone.net]
Sent: Wednesday, June 10, 2009 4:38 PM
To: David G. Dixon
Subject: RE: [sdiy] Tantalums in Yamaha CS20M/CS40M



As I recall during the 70's the tantalum cap cost top dollar and was
considered at the "top of the line" in capacitors.

Here is some of what Wikipedia has to say:

{
Tantalum capacitors possess very low electrical leakage, (high leakage
resistance), and will retain a charge for a long duration, they are also
more tolerant of harsh, hot operating environments unlike standard aluminium
electrolytic capacitors. Tantalum capacitors are relatively expensive,
particularly the military grades, they are not particularly tolerant of
heavy charge and discharge currents, particularly of a repetitive nature and
their effective series resistance, ESR, is quite high when compared to
aluminium electrolytics. As with all electrolytic capacitors, correct
polarity must be observed otherwise the capacitor will depolarize and the
dielectric oxide layer will be reduced back to the metal, reducing the
resistance of the device and causing it to become very hot and possibly
explode. Tantalum capacitors are less prone to "drying out", causing a
decrease in capacitance as is often the case with aluminium electrolytic
capacitors particularly when used in hot environments. They maintain their
designed capacitance under such conditions over long periods of time,
(decades).
}

As you can see the were expected to last a very long time and be extreamly
stable.. However some of the old gear has been around for a very long time,
I wonder if the bad reputation these have with some of post has to do with
caps that are at EOL, or perhaps new but abused. With high ESR it is very
easy to prematurely kill a cap due to ripple current and heat build up. It
is obvious that they would fail in applications that an electrolytic cap
would be fine with. This may be viewed as a defect buy some people who have
tried using them.

- Jerry

-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl]On Behalf Of David G. Dixon
Sent: Wednesday, June 10, 2009 4:07 PM
To: 'Gil W.'; synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] Tantalums in Yamaha CS20M/CS40M


Why would they blow up if they were installed in the right direction?  Do
old tantalums (tantala?) simply blow up on a whim?

> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> bounces at dropmix.xs4all.nl] On Behalf Of Gil W.
> Sent: Wednesday, June 10, 2009 11:52 AM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Tantalums in Yamaha CS20M/CS40M
>
>
> I open up my monstrous CS20M (and my friend's CS40M), and I see a lot of
> tantalums in there. Before one blows up and shorts the thing, do you think
> it will be safe or wise to replace them all with a similar valued
> electrolyte ? Will the sound get worse a bit ?
>
> Particularly the power supply... There are four 1uf/35v tants in there,
> can I just drop 1uf electrolytes instead of them ?
>
> Thanks ;)
>
>
>
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> Synth-diy at dropmix.xs4all.nl
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