DIYmod LOD caps - Page 2

No. There is very little current in a line-level signal (mA at the most).

You could probably use some SMD film caps if you really wanted to bypass your 'lytics.

To answer your questions from the PM, capacitors block DC from getting to your headphones, and you choose your corner frequency so that you get the most musical information to your ears.

What do capacitors do?

Capacitors, when placed in series with a signal, block DC and only pass AC; this goes for both voltage and current. In reality, a little DC gets through, but very, very little compared to what "goes into it." Music is AC, so we like having AC get through. The reason we don't like having DC pass through our headphones (and speakers) is because they can destroy them. With dynamic speakers (as opposed to electrostatic, piezoelectric, etc.), you have a coil of wire surrounding a magnet. The magnet responds to the magnetic field produced by the AC signal, and it in turn creates audible music. These wires are very thin, so if you pass DC through them, the internal resistance of the wire will make it heat up. With enough DC, you can melt the wire, and the speaker will be ruined forever. Capacitors are one way of blocking DC. You can also use DC servos and transformers, but in our case, the capacitor is the best solution.

Choosing a corner frequency

The way you choose your corner frequency is related to your hearing ability. Filters allow us to select which frequencies get through more than others, so it has important ramifications for the audio community. The average human can hear frequencies from 20Hz to 20,000Hz (everyone is different), so we try to design our filters around that. Grouped with the previous section, the capacitor and potentiometer form a high pass filter. What that means is that the filter only allows frequencies higher than its corner frequency (aka cutoff frequency, -3dB frequency) to pass, and frequencies below that frequency are muted. Now, keeping in mind that we want all the audible frequencies at the output of our headphones, we use the characteristic equations of our filters to tune our audio gear to allow those frequencies to get through. Therefore, we choose the lowest frequency to get through our filter to be 20Hz or lower. That way, you get all the bass information that you may be able to hear getting past the filter formed between the diyMod and the potentiometer of your amplifier.

What qusp suggested makes sense. You could put capacitors in the input of your CMoy and be done with it. Any DC coming from any source will be blocked by those input caps. However, be cautioned that DC will flow out of that diyMod's audio signal, so you have to be careful not to use it with gear that doesn't have blocking capacitors. Most commercial products will have them, but it's better to err on the safe side. Build that capped LOD for use with other gear; suppose you try it on someone else's headphones at a meet and you don't want to replace their HD800s.

We're here if you have any other questions, but further research on Google and textbooks will be more fruitful than waiting on us to reply. Come back to us when you hit a snag in your investigation.