[R-390] The total capacitance of capacitors in parallel is equal to the sum of each capacitors

[Bob Camp]

Hi

Well it could be because the laws of physics have been suspended by act 
of congress.

Assuming that both capacitors are working and in the circuit then you 
should have them add when they are in parallel. With a 4x increase in 
the capacitors you should push the low end a bit more than an octave 
down. That's *if* the capacitor is the only thing limiting the low end. 
I would guess that the output transformer drops out somewhere down low.

Do you have anything you can sweep the audio response with? Usually 
that is the only way to be sure you are winning or loosing. A partial 
octave improvement can be tough to hear below 100 Hz or so. It's a lot 
easier to hear below 100 cps.

	Take Care

		Bob Camp
		KB8TQ

On Apr 19, 2005, at 3:23 PM, Barry wrote:

> Okay, pretty much everyone on this list knows this; however, I have a
> question.  I would like to try Chuck's modification where the coupling
> capacitors in the audio deck are increased from 0.01uF to 0.022uF, 
> 0.033uF,
> or more to yield better low frequency response.  I assume the theory 
> here is
> that the higher value capacitors produce a lower capacitive reactance 
> at the
> lower frequencies thereby allowing a greater low-frequency voltage on 
> the
> grid of the final PA enhancing the low-frequency response.
>
> Given the subject line of this post, I proceeded to place 0.033uF 
> capacitors
> in parallel with the existing 0.01uF capacitors.  Theoretically, this 
> should
> have yielded 0.043uF; however, I didn't notice any change in the 
> sound.  I
> assume this is because while the total capacitance is now greater, each
> capacitor acts independently; however, why didn't the 0.033uF 
> capacitors
> still allow the low-frequency voltages and I would still get a better
> low-frequency response?  Is it possible I just didn't notice the 
> difference
> or was my method completely invalid?
>
> Barry - N4BUQ
>
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