Turner Super Sidekick Question

[nomadradio]

The difference between 47 and 50 uf is six percent. The tolerance of the marked capacitance on that kind of capacitor is nearly always ten percent or more. Should not be a significant difference.

A higher voltage rating is almost never a problem. In some circuits you will see an electrolytic capacitor rated for 50 Volts or more even though the voltages on it are under ten Volts.

This is done because the lower-voltage caps tend to have more DC leakage current built into them. No capacitor is a perfect insulator for DC voltage. The higher the voltage rating on an electrolytic, the lower the leakage current will usually be. In a circuit that is sensitive to unwanted DC current from capacitor leakage, using a part rated for more than the circuit's operating voltage is a routine way to improve circuit performance.

Biggest obstacle to this is usually size. Higher voltage ratings also mean a bigger part. If they'll fit they should do the job just fine.

73

 

[Klondike Mike]

Im getting ready to replace the three electrolytic caps on the amp board. What i am wondering is if a 47ufd will work in place of the 50ufd with a bit higher voltage rating? Same for the two 22ufd at 160v rated caps that I bought. 160v is much higher than the originals.

The caps I replaced in my "golden" SSK were;

22uf @ 16v (2)
47uf@ 25v (1)

So, my guess the manufacturer changed from 50 to 47 at some point in time. Regarding replacing electrolytics with voltage ratings way above the replacements, an increase in ESR value goes along with which is not a good thing. See comment below from Robert Kollman, Senior Applications Manager @ Texas Instruments;

https://www.eetimes.com/author.asp?doc_id=1279791

 

[LeapFrog]

The caps I replaced in my "golden" SSK were;

22uf @ 16v (2)
47uf@ 25v (1)

So, my guess the manufacturer changed from 50 to 47 at some point in time. Regarding replacing electrolytics with voltage ratings way above the replacements, an increase in ESR value goes along with which is not a good thing. See comment below from Robert Kollman, Senior Applications Manager @ Texas Instruments;

https://www.eetimes.com/author.asp?doc_id=1279791

Not to side track the thread, but..
Having found two capacitors (each 10 uF) with very different voltage ratings inside the same (tube radio) I made it a point to order some 50V 10uF caps also, instead of using the ones (I had on-hand) rated for several hundred volts.
I'm sure the radio would have worked fine if I used the 10uF cap w/ higher voltage rating, but I've heard what Klondike is talking about before so I made a separate order.

 

[KD8HMO]

Now I'm wondering if I should use the caps that I bought or just order the correct ones. $3 for parts and $10 to ship lol

 

[LeapFrog]

Now I'm wondering if I should use the caps that I bought or just order the correct ones. $3 for parts and $10 to ship lol

If you are just going to replace a few caps in the microphone, I don't think it will
make-or-break-it, you should be fine.

And in fact I probably could have used a 400 Volt rated cap in place of the 25 Volts rated cap and found no appreciable difference in the application.