Help with component function (simple)

[BetaTripp]

Hi there,

Just a simple one. I'm new to circuit design and I'm trying to reverse engineer some circuits to work out how they work but I'm struggling with a few components. What I'm thinking at the minute is that C1/R1 and C2/R3 are HP filters with a cut off of 1k. R1 and R3 could possibly be a voltage divider over the pot to create a gain for the output, but whats puzzling me is why C2 goes to ground and why there is potentially two HP filters. Please correct me if I'm wrong with anything. Circuit below

Thanks!!

BetaBeetroot

https://www.google.co.uk/search?q=t...ei=v3PgVsGOEsG0a6npupgH#imgrc=4nMLu6i3s63z0M:

 

[MikeMl]

Welcome.

Here is the preferred Bridged-T Bass and Treble Boost and Cut circuit when used in the feedback path of an opamp. The first shows what happens as the Treble Pot wiper is moved with the Bass Pot centered and the second is vice versa:

 

[AnalogKid]

There are two high pass filters. One of them is a series leg, and attenuates the low frequencies being passed through to the output. This is the high frequency pass through that most people think of. The other is a shunt leg, and attenuates the low frequencies being shunted off to ground. This is passing the highs to ground rather than to the output, so it actually is a high frequency subtracter. Notice in Mikes plots that unlike a simple highpass circuit, the highs are boosted (or cut) more and more over a range of frequencies, then the boosting (or cutting) levels off. This is the effect of the shunt leg cancelling out the series leg. Adjusting the pot adjusts the ratio of the the series and shunt leg signals being summed into the output. When the pot is centered, the ratio is 1:1 and the freq response is flat.

ak