PFM Subsonic Filter

This unique feature is legendary with many AudioControl fanatics for its ability to fine-tune the bass response of any system. Why waste power on nasty subsonic information when your Programmable Frequency Match (PFM) filter can help you clean things up?


These modules have KOA Speer carbon film resistors (5% tolerances) & Kester solder. If you want to be spot-on with your frequencies, we also carry modules with 1% tolerances, metal film resistors. Check out our other modules.

Will work with AudioControl units that accept 14-pin IC modules (18 dB/octave slope)


Available modules (5% tolerances):

1.0 Hz, 5.0 Hz, 7.0 Hz, 10 Hz, 13 Hz, 15 Hz, 20 Hz, 22 Hz, 25 Hz, 27 Hz, 30 Hz, 33 Hz, 40 Hz & 45 Hz (more to come)


Modules sold individually.

We resistance test every module before it’s shipped out for correct tolerances.

Bulk discounts available. Please inquire for more info.

If you need a different frequency, contact us. We’ll custom build one for you.
Thank you for supporting our small business! Have a great day!



What's the difference between 1% and 5% tolerances?
https://www.electronics-tutorials.ws/resistor/res_2.html

EXCERPT...Hopefully by now we understand that resistors come in a variety of sizes and resistance values but to have a resistor available of every possible resistance value, literally hundreds of thousands, if not millions of individual resistors would need to exist. Instead, resistors are manufactured in what are commonly known as Preferred values.

Instead of sequential values of resistance from 1Ω and upwards, certain values of resistors exist within certain tolerance limits. The tolerance of a resistor is the maximum difference between its actual value and the required value and is generally expressed as a plus or minus percentage value. For example, a 1kΩ ±20% tolerance resistor may have a maximum and minimum resistive value of:

Maximum Resistance Value

1kΩ or 1000Ω + 20% = 1,200Ω

Minimum Resistance Value

1kΩ or 1000Ω – 20% = 800Ω

Then using our example above, a 1kΩ ±20% tolerance resistor may have a maximum value of 1200Ω and a minimum value of 800Ω resulting in a difference of some 400Ω!! for the same value resistor.

In most electrical or electronic circuits this large 20% tolerance of the same resistor is generally not a problem, but when close tolerance resistors are specified for high accuracy circuits such as filters, oscillators or amplifiers etc, then the correct tolerance resistor needs to be used as a 20% tolerance resistor cannot generally be used to replace 2% or even a 1% tolerance type.