Consider the following schematic. Specifically the input R-C network R1, R2, C5, C6 where:
R1, R2 = 90.1K
C5 = 10 nF polypropylene
C6 = 22 uF electrolytic
I am looking at this sideways thinking it makes little sense, from a sonic perspective.
The R-C combination of R1 and C5/C6 in parallel form a high pass filter with a -3dB Cutoff Frequency of 0.8 Hz. And I am thinking that anything above the -3dB point causes R 1 and R2 to form a parallel network with a combined effective resistance approximately 45.5K ohms, nearly the typical input impedance of a MM phono stage.
My question now is, why the heck do you want an aluminum electrolytic in such a sensitive area?
Wouldn't a decent film capacitor about 1.0 uF accomplish almost the same thing? It's R-C calculated value against a 91K resistor -3dB point is 1.75 Hz.
Then simply remove the offending electrolytic at C6 and install a 1.0 uF poly type in its place?
What say the more educated than me?
R1, R2 = 90.1K
C5 = 10 nF polypropylene
C6 = 22 uF electrolytic
I am looking at this sideways thinking it makes little sense, from a sonic perspective.
The R-C combination of R1 and C5/C6 in parallel form a high pass filter with a -3dB Cutoff Frequency of 0.8 Hz. And I am thinking that anything above the -3dB point causes R 1 and R2 to form a parallel network with a combined effective resistance approximately 45.5K ohms, nearly the typical input impedance of a MM phono stage.
My question now is, why the heck do you want an aluminum electrolytic in such a sensitive area?
Wouldn't a decent film capacitor about 1.0 uF accomplish almost the same thing? It's R-C calculated value against a 91K resistor -3dB point is 1.75 Hz.
Then simply remove the offending electrolytic at C6 and install a 1.0 uF poly type in its place?
What say the more educated than me?
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22uF is about 700 ohms at 10Hz, and 350 ohms or less through the audible band. Replacing it with a larger value electrolytic would be the obvious way to reduce these values and thus reduce any possibility of distortion, but the signals we are talking about are very small and you won't see significant non-linearity at such low levels I would reckon - distortion in passives is strongly related to signal level, so you might want to up the voltage rating of the cap as well as its value, but usually low signal levels mitigate distortion very effectively.
BTW you can't just pull the electrolytic, its carrying the signal current! You could replace both caps with a piece of wire if you wanted, but that would put DC into the cartridge, which you probably don't want (!)
BTW you can't just pull the electrolytic, its carrying the signal current! You could replace both caps with a piece of wire if you wanted, but that would put DC into the cartridge, which you probably don't want (!)
I'm not wanting to pull the caps and replace them with straight wire.
I was thinking that replacing both with a single (or even the 22 uF electrolytic) 1.0 uF poly type would maintain a sufficiently low passband while improving the sound.
Or am I thinking this wrongly?
I was thinking that replacing both with a single (or even the 22 uF electrolytic) 1.0 uF poly type would maintain a sufficiently low passband while improving the sound.
Or am I thinking this wrongly?