tantalum caps

zacharybroyles · September 04, 2005, 03:29:15 PM

do they have a postive and negative leads? I noticed some I have have a little + above the right leg. I've getting ready to mod a BD-2 and was curious about this. will it matter how I solder these in? Help

KORGULL · September 04, 2005, 03:43:46 PM

They do have positive/negative leads and it absolutely will matter how you solder them in. Treat them the same as you would a (polarized) electrolytic cap.
Most of them have the positive lead marked with a + like you mentioned.
Tantalum caps cannot tolerate reverse polarity for long and will pop if not hooked up right.
*Edited for spelling error

sir_modulus · September 04, 2005, 03:46:57 PM

Yes it does and yes they often do. Tantalums (the power ones) do have a polarity and I myself have had one catch on fire when I wired it in wrong (power filter). In the blues driver...where are you using them and what value? If they're replacing electrolytics, then just put the +ve where the old positive was. If they're replacing small signal caps....I'd get some new ones. There is a way to wire them in, in place of signal (non polarized) caps...but they'll sometimes fail after a while (depends on the circuit). I just use tantalums to replace electro's for pirce and availability.

Cheers,

Nish

Edit: Darn Korgull you beat me to it!

formerMember1 · September 04, 2005, 03:59:56 PM

hey guys talking about tantalum caps,
I know some say there is no difference between cap material as far as tone goes and some say there is,
I could hear a difference if i use all ceramic caps in a circuit and switch them out for metal film/mylar, But when ever a pedal needs a tantalum cap i always replace them with metallized polyester or something,

Anyway the reason for my post is:
Is there places where you have to use tantalum caps?

a friend changed the Non Polar(NP) electros and tantalum caps in a tubescreamer and i heard a difference from when it was stock, and they were the same values just different material.

Mark F · September 04, 2005, 04:14:58 PM

Quote from: formerMember1hey guys talking about tantalum caps,
I know some say there is no difference between cap material as far as tone goes and some say there is,
I could hear a difference if i use all ceramic caps in a circuit and switch them out for metal film/mylar, But when ever a pedal needs a tantalum cap i always replace them with metallized polyester or something,

Anyway the reason for my post is:
Is there places where you have to use tantalum caps?

a friend changed the Non Polar(NP) electros and tantalum caps in a tubescreamer and i heard a difference from when it was stock, and they were the same values just different material.

I think one of the main reasons for using tantalum caps is real estate considerations. A relatively large amount of capacitance can be packed into a small area utilizing tantalum caps as opposed to electrolytic caps. Hope that helps answer your question formerMember1! :wink:Also, I don't think tants dry out as they age like electros.

formerMember1 · September 04, 2005, 04:17:13 PM

it does thanks!! :wink:

I forgot about that, and it does make sense too :lol:

zacharybroyles · September 04, 2005, 06:36:13 PM

OK, thanks for the help guys. I am replacing electrolytic caps and I was looking at the board and noticed one of the legs had a circle and the other side has nothing. The caps are black and with the side that the circle is on the board the cap has a gray bar with either black lines or little rectangular boxes. I assume that the side that is circled is the negative side?

The tantalum caps I have at 10 uf and have a little dotted line with a + on the right side, that lead is also longer so I guess thats the positive lead. SOOOO....

when I replace the elec. cap for a tant I need to put the positive side on the side with NO CIRCLE and the other side of the cap where the circle is?

Thanks so much for the help, I've never used tantalum caps before

zacharybroyles · September 04, 2005, 06:38:29 PM

this is for a Keeley Phat mod for the BD-2 by the way

Peter Snowberg · September 04, 2005, 07:16:49 PM

Tantalums....

...have long life
...are smaller than aluminum electyrolytics
...have a very low ESL (makes them good for power filtering)
...have a very low ESR (makes them good for power filtering)
...are not perfectly linear
...show hystersis unless under heavy DC bias :shock:
...are not forgiving of reverse bias (!)

http://members.aol.com/sbench102/caps1.html (tant page)
http://members.aol.com/sbench102/caps.html (intro)

zacharybroyles · September 04, 2005, 07:43:37 PM

that doesnt really answer my questions

Toney · September 04, 2005, 08:08:06 PM

OK, I ve just done some considering re tants too.

I'm doing a Distortion plus and a Ts808 at the moment, both of which have em. In both cases I've decided to use them for now, so that as I modify swap in /out components, I will have a baseline for how the circuit sounds original, with my gear. The distortion + uses the pretty crude 741 op amp but many consider it "part" of the overall sound, so thats in there too
It depends where in circuit they lie and how the whole thing reacts to you rig.
So its the suck it and see approach....

Many a horrid pedal can have its unique charms with the right gear, sometimes brilliantly.

Mark F · September 04, 2005, 10:00:22 PM

Quote from: zacharybroylesOK, thanks for the help guys. I am replacing electrolytic caps and I was looking at the board and noticed one of the legs had a circle and the other side has nothing. The caps are black and with the side that the circle is on the board the cap has a gray bar with either black lines or little rectangular boxes. I assume that the side that is circled is the negative side?

The tantalum caps I have at 10 uf and have a little dotted line with a + on the right side, that lead is also longer so I guess thats the positive lead. SOOOO....

when I replace the elec. cap for a tant I need to put the positive side on the side with NO CIRCLE and the other side of the cap where the circle is?

Thanks so much for the help, I've never used tantalum caps before

That sounds correct to me. However, having not seen the caps myself I couldn't guarantee it. The Neg leg of an electro is usually labeled as such and the Pos. leg of a Tant. is usually labeled with a +, although it is sometimes very hard to see , and the Pos. leg is usually longer. So, yes that is what I would do.

sir_modulus · September 04, 2005, 10:04:11 PM

Quote from: zacharybroylesOK, thanks for the help guys. I am replacing electrolytic caps and I was looking at the board and noticed one of the legs had a circle and the other side has nothing. The caps are black and with the side that the circle is on the board the cap has a gray bar with either black lines or little rectangular boxes. I assume that the side that is circled is the negative side?

The tantalum caps I have at 10 uf and have a little dotted line with a + on the right side, that lead is also longer so I guess thats the positive lead. SOOOO....

when I replace the elec. cap for a tant I need to put the positive side on the side with NO CIRCLE and the other side of the cap where the circle is?

Thanks so much for the help, I've never used tantalum caps before

First off...all caps have a bar with some form of lines/dots/stuff on one side. That's the negative side

Yes, that's the positive lead.

You put the negative lead of the tatalum cap where the negative lead of the old cap was, and vice versa for the other. If you really are not sure of the polarity of the electro's go look at the schematic (bit too tired to search it up right now..sorry)

Cheers,

Nish

zacharybroyles · September 05, 2005, 12:13:35 PM

thanks guys

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tantalum caps

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