Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dragonworks on September 16, 2021, 04:28:16 pm

Title: Stupid newbie question 101
Post by: dragonworks on September 16, 2021, 04:28:16 pm
Is there such a thing as non polarized electrolytic capacitors? I replaced some caps in an amp, two of them looked like electrolytics so I replaced them with electrolytics. When checking the schematic I see they are not electrolytics. So, I go to antique electronic supply and newark electronics to look for the caps, 25uf @ 15V and every single cap listed on both sites says they are electrolytics. I cannot find any in that range that are not listed as electrolytics?ThanxJ.D.
Title: Re: Stupid newbie question 101
Post by: sluckey on September 16, 2021, 04:53:25 pm
Show us the schematic.

25µF @ 15V is most likely an electrolytic.
Title: Re: Stupid newbie question 101
Post by: dragonworks on September 16, 2021, 05:03:52 pm
I will post it again, it is the Magnatone M15.The caps are in the reverb circuit, one on pin 3 of the 12AU7 and one on pin 8 of the 7025.Looking again, they are electrolytics. It has been a long time. Now I have to look and see which side is plus or minus and if I have them in correctly.
Title: Re: Stupid newbie question 101
Post by: dragonworks on September 16, 2021, 05:09:00 pm
Okay, the straight side is the plus side. I usually see them marked on the schematic with a plus sign. Now I have to go down and make sure they are in correctly, I put them in quite awhile ago.signed stupid newbie.
Title: Re: Stupid newbie question 101
Post by: dragonworks on September 16, 2021, 05:47:12 pm
They are in correctly.
Title: Re: Stupid newbie question 101
Post by: Keppy on September 16, 2021, 11:20:46 pm

Yes, they exist. I've never seen an amp that required non-polar electros, though. They're generally used where you can't be sure which side of the cap will be at a positive voltage with respect to the other. Electros in tube amps usually have one side grounded, so non-polar isn't necessary.


https://smallbear-electronics.mybigcommerce.com/electrolytic-radial-50v-non-polarized/