Vintage Synth Repair

Thanks for your perfect explanation!

Daniel Forro


On 9 Apr, 2013, at 2:03 AM, 65 Lotus wrote:

>
>
> Internally tanatlums look like a sponge where their charging surface  
> area is exposed in 3-dimensions, whereas electrolytics are a couple  
> of wound, flat pieces of foil.
>
> Due to their inherent structure, tanatalums charge very quickly as  
> the 3-D surface gets easily flooded with electrons, whereas for  
> electrolytics, the electrons have to spread around the plate to be  
> saturated. That takes time.
>
> So, tantalums are very good for high frequency cap duties, like on  
> the crystal (clock) circuits. For power rails, electrolytics are  
> fine of course, but for anything that's a high frequency circuit,  
> I'd stick with a tantalum if was spec'ed that way to begin with.
>
> Tantalums are very unfogiving of overvoltage which is what usually  
> kills them. Once they're saturated, the slightest voltage over their  
> rating will do them in, where they melt into a short. They work  
> great when used properly in a circuit where the probability that  
> they'll ever see a spike is nil. Replacing a tant with one with a  
> larger rating will slow down the saturation time, so again, I'd just  
> replace it with the original rating component. I like the Vishay  
> brand which is what we use in the aviation industry where I work.
>
> I'm no expert (I'm a mechanical engineer however), but I spent a few  
> hours researching the ins-and-outs of tants one day right before I  
> did a full recap on my OB-Xa. If it was tantalum, it stayed that way.
>
> Scott in Ohio
>