Capacitor Swap

[SparkyCal]

Hi guys. i am looking at a circuit that calls for a 47uF capacitor. As it does not specify polarity, i assume it is a film capacitor.

The circuit is for a 5th Gear Overdrive. Sorry..i can't find it at the moment.

I don't have film capacitors of that size. I do have an electrolytic capacitor that is 47uF. Do you think i can use that?

 

[kpatz]

Can you post a schematic?

 

[SparkyCal]

I just found it. Please see attached.

 

[Nanren888]

Sure. No problem. Plus (+) is up.

 

[Cannonball]

Yes, but make sure that you connect + lead to the emitter and the - lead to ground.

 

[Audioguru]

The obsolete transistor (you can use two common transistors wired like in the darlington transistor symbol) is drawn wrong and is actually a darlington.
What a horrible circuit, but it might make a unique kind of severe distortion.
The 47uF capacitor does not pass audio, instead it shorts it to ground so an electrolytic with the - wire to ground is fine.

 

[bertus]

Hello,

I noticed that there are two diodes (a diode and a red led), but there is not given which is which.
Here I found an older version which does have that information:



Bertus

 

[Nanren888]

The 1N4148 diode is pretty much equivalent to the 1N914.
The capacitor swap should be fine, as long as the positive terminal "+" is upper, that is, the end towards the transistor, and ultimately, through the transisor, towards the + of the battery.
The 22uF capacitor is a low impedance in the audio current path, meaning that the circuit has high gain for the parts of the audio signal near zero volts.
With this substantial non-linearity, the effect of the leading gain control potentiometer, variable resistor,will be to change the sound. The later one is simply a volume control

 

[SparkyCal]

Thanks to all and thanks Bertus for the alternative schematic. I read somewhere that swapping capacitors is usually not an issue when swapping electrolytic sin place of film, and that people shy away from doing so because electrolytics take more room. Not sure if that is true