Hi-Pass Filter

[30hertz]

Hi all,
Anyone got, or know of, a schematic for a really good hi-pass filter? I'm looking to cut everything below around 20-30Hz out of my bass signal to give my amp/speakers an easier time. All ideas gratefully received. Thanks chaps!

[chptunes]

You could wire up a simple Hi-Pass filter, just two components.. stick it inside your bass' control cavity, or a 1590a enclosure.

I believe a 10k Resistor and a 0.68 uf Capacitor would be a good starting point.

Here's a calculator and diagram: http://www.muzique.com/schem/filter.htm

[30hertz]

Thanks. I'd be more likely to put it in a separate enclosure, as I don't want to go mucking about with the active guts in my bass.
I've also found this circuit and was wondering if it'd be any good?

http://www.eeweb.com/blog/circuit_pr...gh-pass-filter

[Trey jr.]

I'm pretty new to all of the circuitry stuff. I'm wondering if the schematic from the second post (the muzique link) is active or passive?

[Trey jr.]

Caps and resistors are both passive, so the circuit should be passive, right?

[Big John Studd]

Originally Posted by Trey jr.

Caps and resistors are both passive, so the circuit should be passive, right?

You're absolutely right. It is a passive filter. By itself it will function fine as a unity gain high pass filter. But when you connect a guitar pickup there will be some attenuation across the band (best case) of the guitar signal. A more realistic case is that you now actually have some sort of an RLC circuit going on due the inductance of the guitar pickup...this can screw you up across the frequency range of the guitar and have the effect of disproportionally attenuating some high end signal.

[FenderLover]

I ran into this a while back. Sounds like exactly what you're looking for.

http://www.metalguitarist.org/forum/...-bass-cut.html

There isn't any content below 41Hz on a bass, so cutting anythig below that won't be too noticeable except for rumble noise.

This circuit can be be assembled externally, but it is simple and reversible, so maybe just give it a shot. I found it useful.

[tjk3052]

Originally Posted by 30hertz

Thanks. I'd be more likely to put it in a separate enclosure, as I don't want to go mucking about with the active guts in my bass.
I've also found this circuit and was wondering if it'd be any good?

http://www.eeweb.com/blog/circuit_pr...gh-pass-filter

A simple resistor and capacitor can make a high pass filter that would be considered passive because there is no amplification. Filtering certain frequencies causes a volume drop, so if you don't want that, you need to look for active filters. The link above is called a Sallen Key filter, and is an active, 2nd order filter, which would be a great choice for you. A 2nd order filter has a steeper drop off of frequency - a more pronounced effect. Google Sallen Key filter for more info...

Here's an online tool for different filter designs:
http://sim.okawa-denshi.jp/en/Fkeisan.htm

When I was designing an eq pedal for myself I also used "Filter Free", a filter design program. There's others that are free as well, I think HP even has one.