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Rickenbacker cap .0047mF - What is the cut off frequency?
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Author:  laban1 [ Sat Oct 22, 2011 1:38 am ]
Post subject:  Rickenbacker cap .0047mF - What is the cut off frequency?

Hi!

I'd like to try the vintage tone circuit with the .0047mF cap serial with the
bridge vol-pot. This is for guitar, i read forums mostly of bass.
I've done some research. It's a hipass filter.

So - What is the cut off frequency?
http://hyperphysics.phy-astr.gsu.edu/hb ... ilcap.html

If the cap is the same (.0047mF micro), it depends of the R, calculations give
R=250k > 68 Hz
R=330k > 102,5Hz
R=500k > 135 Hz

I read somewhere that Lo Mid would be cut out, so is this right?
Has someone measured this? If so then please tell R of the Vol.pot.

I heard that this vintage tone circuit would cut out Lo mids (250-500Hz?),
but it seems that only bass is cut out.

Are my calculations right here or am I forgetting something?

Has anyone measured the cut off frequency?

Thanks for any input!

Author:  songdog [ Sat Oct 22, 2011 7:58 am ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

laban1 wrote:
Hi!

If the cap is the same (.0047mF micro), it depends of the R, calculations give
R=250k > 68 Hz
R=330k > 102,5Hz
R=500k > 135 Hz

Are my calculations right here or am I forgetting something?


I think you mixed up 250K and 500K - my calculations show the frequencies at those resistances were swapped in your table.

Keep in mind this is only an approximation, and only really applies when the volume knob is up all the way, and the pickups are isolated by using the Ric-o-sound output. Turning down the volume knob lowers the resistance to ground, thus raising the corner frequency. Taking output from the mono jack always connects both volume pots in parallel, even if only the bridge pickup is selected.

If both pickups are on, the situation becomes much more complicated.

I think the .0047 cap was only used on the 4001 bass family. I'm not aware of it ever having been used on guitar.

Author:  gtburge1 [ Sat Oct 22, 2011 10:16 am ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

try iiipopes vintage tone mod. post
lots of info here

GTB

Author:  laban1 [ Sat Oct 22, 2011 9:28 pm ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

Hi, yes I swapped the 250k and 500k, thanks!

"Taking output from the mono jack always connects both volume pots in parallel, even if only the bridge pickup is selected."

Have no rickosound, Looking at wiring for mono http://www.rickenbacker.com/pdfs/19511.pdf

Yes, this is because of the blender, right?
So if I have 330k pots (as an example) leaving both on max output,
then I would have half the resistance, 165k > 205Hz

But wait, it looks as the blender 500k is on (and fixed value) even if I use bridge only, then 500k // 330k neck (max) > 200k (close)

So then its 200k//330k (bridge) = 124k > 273 Hz
This would be the minimum cut of frequency and turning any pot would cut out even more.

Is this right? Any comments would be appreciated!

Author:  cassius987 [ Sun Oct 23, 2011 7:59 am ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

I believe it's a little above 100 Hz based on real-time spectra I have watched after toggling the cap back and forth.

Author:  laban1 [ Sun Oct 23, 2011 10:12 am ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

Hi Cassius!
That was intresting, was that FFT-analysis?
Which guitar/bass was it?
Did you use the ric-o-sound mono? Was this Bridge PU only on the swich?
Do you know what pots it was?

Author:  laban1 [ Thu Oct 27, 2011 10:30 pm ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

Anyone,... any input?

Author:  cassius987 [ Fri Oct 28, 2011 2:22 pm ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

laban1 wrote:
Hi Cassius!
That was intresting, was that FFT-analysis?
Which guitar/bass was it?
Did you use the ric-o-sound mono? Was this Bridge PU only on the swich?
Do you know what pots it was?


Modern 4003. Bridge pickup soloed, mono. 330k pots (more like 300).

Author:  coolhandjjl [ Sat Oct 29, 2011 11:58 am ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

I just ran a quick RTA on mine- 200hz and above seem unaffected, but the graph begins to noticeably change between 100 and 200 per the cap position. At the 100hz mark and below, its an obvious cut.

Author:  iiipopes [ Sun Oct 30, 2011 5:30 am ]
Post subject:  Re: Rickenbacker cap .0047mF - What is the cut off frequency

With the fundamental of the low E string being 80 Hz, this makes sense. Also, remember it's not just the cutoff frequency. All frequencies above the cutoff are shifted 90 degrees, which is a major element contributing to the jangle.

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