1. ## Stiffening capacitors in a wall outlet

Just a random thought, but if I were to wire two ~700uF stiffening caps in series between a piece of equipment and the wall socket it is plugged into (One on + line, on one - line), what kind of effect would it have?

2. ## Re: Stiffening capacitors in a wall outlet

120VAC -> 700uF capacitor -> load

According to this calculator;
http://www.kusashi.com/reactance-c.php

60hz is the AC wall socket frequency.

Capacitive Reactance [Xc] = 3.78 Ohms

Equivalent to placing a 3.78 ohm resistor in series with the AC line.

If this is wrong let me know

Two 740uF in series would net 370uF and Xc = 7.1 Ohms

If placed across the AC, seems like a 17A draw? /hehe

fun times

4. ## Re: Stiffening capacitors in a wall outlet

That would be wiring the cap directly to the outlet. I'm planning on running it between the wall and a tube amp that doesn't draw anywhere near 17 amps.

5. ## Re: Stiffening capacitors in a wall outlet

Originally Posted by Raven
That would be wiring the cap directly to the outlet. I'm planning on running it between the wall and a tube amp that doesn't draw anywhere near 17 amps.
It won't be a 'stiffening capacitor' in that application It's a 'waste of time capacitor'.

Also, capacitors have polarity, some don't. Placing polarized capacitors in AC can be bad news.

If you want stiffening capacitors you need to examine the tube amplifier power supply.

You don't think 120VAC x 20A for a typical house circuit is a 'stiff' 2400VA power source for a little tube amp ?

6. ## Re: Stiffening capacitors in a wall outlet

Yeah, I'm not exactly sure what the point of this exercise is...

7. ## Re: Stiffening capacitors in a wall outlet

I am looking for an inexpensive way of conditioning the power from a standard 110 outlet to combat brownouts and spikes.

8. ## Re: Stiffening capacitors in a wall outlet

Sounds like the power tranny and/or buffer cap aren't doing their job if you're getting lots of inducted noise...

9. ## Re: Stiffening capacitors in a wall outlet

If by "Power Tranny" you mean the giant transformer that changes the 110AC input to whatever voltage the rectifier takes in, it's very feasable.

If by "Buffer Cap" you mean the giant stiffening capacitors that this thing seems to have one or two too many of, they've already been replaced. Sprague Atoms in their place via tubesandmore.com. =)

10. ## Re: Stiffening capacitors in a wall outlet

You have a EL84 single ended pentode amp, right? Post a picture of it, I have basically the same amp I'm restoring as well...

11. ## Re: Stiffening capacitors in a wall outlet

Pics are easier said than done when you don't have a camera. =(

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