All Questions
88
questions
3
votes
2
answers
369
views
What type of cap would you use to block DC on a microphone-level audio line (unbalanced)?
I need to block a DC voltage on a microphone line, and a bit of research shows that MLCC is a bad idea because they can mechanically ring from vibration.
Question:
What type(s) of capacitor could be ...
- 2,088
0
votes
3
answers
84
views
Polarized capacitor type identification
I need to know what is the type of this capacitor. Never seen these before. It is polarized (red side is +) and rated 4MFD (4uF I would guess) 25v. I also would like to know what would be an ...
- 13
0
votes
1
answer
62
views
Options for line output doubling as headphone output
As the title says, I'd like a combined line/headphone audio output with the following design criteria:
ideally driven from 5V single supply (12V available, but noisy)
flat frequency response, also in ...
1
vote
2
answers
68
views
Do I need to implement a DC Offset for this audio signal?
I'm using the TPA3137 Class D Amplifier to amplify an audio signal coming from a Summing Amplifier. The TPA3137 amplifier does accept differential inputs, but my intention was to use a single ended ...
- 1,195
1
vote
2
answers
61
views
Aluminium electrolytic capacitors in an AC circuit
Looking through the datasheet for the TPA3123D2, I have noticed some confusing symbol usage and positioning. From my understanding, aluminium electrolytic capacitors can only be 'charged' on the ...
- 592
0
votes
3
answers
136
views
What are these resistors and capacitors doing in this audio CODEC circuit?
I'm implementing the VS1053 Audio CODEC IC on a PCB design where I will be using it along with a class D amplifier that will connect to a pair of 8 ohm speakers. I'm looking at SparkFun's MP3 Player ...
- 1,195
0
votes
4
answers
240
views
How can I remove DC from an audio signal?
I am trying to "isolate" an audio signal that is transmitted on top of a 24V (DC) power supply voltage.
This construct is used in door intercom systems from TCS.
The audio signal is the ...
- 141
0
votes
1
answer
104
views
Where should the audio-input be available in this RF circuit?
Let me show you what I have tried so far. First of all, the circuit below has been tested and this one works for sure. The audio signal can be heard on an FM radio at 100MHz.
The second below is ...
user321220
0
votes
2
answers
169
views
Can we place capacitors parallel to the speaker (30 ohm headphone) and aux jack?
I am working on an audio amplifier PCB circuit, where I have used LM386 as an amplifier, an aux jack for audio output, and a small speaker of headphones (30 ohm).
I have two 220 uF molded and one 470 ...
2
votes
1
answer
109
views
Placement of filter capacitors in a circuit with multiple audio outputs
I have a multiple output stage of an audio circuit as in the picture attached.
I want to add a capacitor to eventually filter any DC at the output, therefore I placed a RC filter 10uF/100k(0,16 HZ) ...
- 53
0
votes
0
answers
122
views
60 Hz buzz on output of DC power supply
I have a 120 V AC to 5 V DC power supply for an audio board. I’m getting the 60 Hz buzz on the output and getting about 44 V AC on the DC output as well. I already replaced two capacitors that were ...
- 1
4
votes
3
answers
196
views
Multiple feedback bandpass filter passband gain doesn't match calculation nor simulation
I designed a couple of bandpasses for an audio project, 15 in total. Only 3 of those 15 bandpasses show a passband gain which match my calculations and simulations.
What could cause this gain mismatch?...
- 41
1
vote
3
answers
86
views
Stereo audio processor: help with capacitors
I'm building a small audio processor board that uses the Silan Microelectronics SC7314 and exclusively THT components. I've recycled this chip from a malfunctioning Philips Home theater.
The thing is ...
- 183
2
votes
1
answer
479
views
Importance of DC blocking capacitor type when we don't care about audio quality
I am working on a board design which is very limited in space. I am taking input from a passive guitar pickup and sending it through a high impedance buffer op-amp, a low pass filter, and then a non-...
- 65
1
vote
2
answers
322
views
Identifying strange SMD audio capacitor
There is a a bypass capacitor in the path of the audio signal on a board (from B&K) which feeds a microphone with a few mAs of current in CCLD (constant current line drive) mode.
I don't know its ...
- 551