Questions tagged [audio]

Questions about designing electronics for measuring, processing, and amplifying audio signals.

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1answer
89 views

Guitar amplifier repair: burnt fuse, capacitor, what else?

A friend has asked me to take a look at his guitar amp: Peavey Valve King VK212. Problem: suddenly the amp stopped working during operation and the status lamp went off. First reaction: fuse ...
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3answers
1k views

Amp troubles - noisy TEA2025

Recently I got my hands on a small amplifier board containing two TEA2025 ICs. Not sure what had it been used in previously, but the sound was acceptable, at least when removing some resistors that ...
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1answer
324 views

getting noise when connecting speaker out of sim800l to raspberry pi

i was trying to make a roaming device which helps me route my calls through internet, to save my bills while on international roaming. my setup goes like this: gsm module sim800l, raspberry pi4, a ...
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1answer
52 views

How to calculate the input impedance and transfer function

I have the following circuit, that is used as a signal conditioning circuit in a audio system project. I am trying to calculate the transfer function and the Zin(input impedance) and Zout(output ...
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2answers
121 views

Symmetrical power supply: Rail fuses useful or dangerous?

I'm designing/testing power amp stuff with symmetrical power supplies (43V-0-43V). In the next future I'm planning to control all safety/healthy stuff (like over current / over voltage / temperature ...
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1answer
54 views

TRS connector for noice cancelling headphones has 5 wires inside cable, instead of 4

Scenario: 3.5mm TRS audio connector on a pair of Panasonic RP-HC200 Noise Cancelling headpohones is damaged, so I cut it off and I'm going to replace the connector from another pair. After cutting and ...
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2answers
411 views

Unstability with tda 2002 bridge configuration

I'm trying, for MONTHS (obviously not everyday, but I spent at least more than 80 hours on this) to do a 15 W audio amplifier with two TDA 2002's in a bridge configuration, following the circuit ...
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5answers
108 views

Why is output power such a meaningful quantity in speakers?

Loudspeakers, for example, should be impedance matched to deliver the highest power from the source to the speakers. But why do we care about power so much? A speaker is at its simplest, a coil around ...
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1answer
42 views

How Can I Fix a Fraying Earbud Cable? [closed]

My KZ earbud is broken, I don't hear anything from the left speaker. After a quick inspection I noticed the cable is fraying. The cable is detachable but I don't want to buy a new one. Do you think I ...
2
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1answer
103 views

How can I convert an audio PDM bitstream into analog form?

I have collected PDM bitstreams from MEMS microphones and I'm looking to convert them into analogue form. Does anyone know some practical implementation details on how to do this (beyond a quote from ...
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0answers
46 views

Adding a CV in to a simple oscillator

I am using an XR2206 IC to make a simple oscillator module. The documentation shows that it has a VCO as a part of the IC, and uses a variable resistor loop and a capacitor loop to control frequency. ...
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1answer
306 views

Line level detection using ADC from a passive summing box

I was looking for a way to detect a line-in device transmitting audio. I got the idea to use ADC for this from this question: How to detect line level audio signal? I already have a 4-channel ADC (...
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1answer
44 views

How can I make a L+R+mic audio dongle to record an Android phone's own output?

I'm looking for a way to wire the stereo output of a device into its own mono microphone input. This will be soldered as a 4 pin 3.5mm TRRS audio jack. I need to record the output of my smartphone on ...
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2answers
65 views

Audio Demos on DE10 Standard not Working

I bought the Terasic DE10 Standard and am having issues trying to run the demos related to audio. I am trying to run the two demos, DE10_Standard_Audio, and DE10_Standard_i2sound, while connecting ...
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1answer
53 views

Get clean line-level audio signal from a sound generator chip that is designed to drive a transistor as amplifier

(I removed both of the two old questions since they are going wild and off-topic, but the main concept is the same, just as title states. Also some details are clarified and informations are appended.)...
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3answers
127 views

Troubles on powering two (audio) circuits with single voltage source

I have a simple audio circuit that needs to be amplified. The circuit is a CMOS based circuit, running on 9V coming from a 12V battery pack stabilized with a 7809 IC. I have also an amplifier circuit ...
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1answer
102 views

How will wire wound resistors affect the synth's sound?

I am soldering up Music from Outer Space: Noise Toaster synthesizer. The guy who designed it said that carbon resistors should be used ("The resistors should be carbon composition or carbon film&...
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2answers
340 views

Quick question. Will this mono/stereo switch system work on my mixer panel?

So basically, I designed a mixer panel for monitoring my band when we play live. However, some of us play with a stereo in ear monitoring system and some of us use a mono speaker by their feet. I don'...
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6answers
116 views

10Ω series resistor in output of headphones amplifier

I managed to reverse engineer a headphone amplifier in a USB DAC that I bought on aliexpress. As I expected there is a electrolytic capacitor in series to the output, but there is also a 10Ω resistor ...
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1answer
71 views

Hardware that can generate chirp audio signal

Basically I would like to generate chirp audio signal that sweeps from 16 kHz to 18 kHz, the signal lasts about 100 ms, no restrict requirements on the sound volume. I am able to generate such chirp ...
1
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1answer
33 views

Is it relatively simple to design an ADC to ADAT interface with only a Toslink port?

For this project (I'm an experienced audio engineer but a relative beginner in electrical engineering) I really want to integrate a simple ADC to ADAT circuit in a patchbay I'm building so that I have ...
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1answer
30 views

Right approach to boost the current of a signal to drive a speaker

I have a circuit which can produce three different waveform signals ( Square, Sine and Triangle). The output amplitude of these signals goes from +5V to -5V Peak to peak. However the output from this ...
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2answers
113 views

Infant cry detector

I want to use an electret microphone to detect infant cry. I came up with this design: According to those papers: Pitch Analysis of Infant Crying Frequential Characterization of Healthy and ...
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1answer
71 views

Can a voltage divider be used for (input) jack detection?

I would like to detect when a jack is plugged into my connector. The circuit looks like this: One end of the jack is connected to a speaker, and the other to an audio source, such as a phone or mp3 ...
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2answers
72 views

Op-amp unity gain buffer introduces distortion in the LM386 circuit with high gain factor

I'm building a simple mixing stage, lowpass filter, and final amp in sigle supply (9v battery). I started from the LM386 circuit on the data sheet. It had a lot of distortion which was solved with the ...
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1answer
43 views

Connecting cell phone and computer audio through TRS and TRRS 3.5 mm audio jacks

I am trying to connect the computer audio output to the cell phone audio input and vice versa. There are two connection designs because I need to be able to connect both to a desktop and a laptop ...
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1answer
529 views

How would a transistor's hFE affect a phase shift oscillator?

I have a phase shift oscillator circuit from a drum machine that I would like to reproduce as faithfully to the original as possible. My problem is that the 40 year old design uses a transistor (...
2
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1answer
458 views

How to DIY BaoFeng radio-to-soundcard cable?

I've got a cheopo BaoFeng UV-5RE that I'd like to try as packet radio. I've snipped the plug off of the headset that came with the handheld, soldered it onto some breadboard cables, and did the same ...
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1answer
405 views

My BJT audio amplifier circuit isn't working as expected

I am trying to design an audio amplifier circuit using BJTs. These are the requirements of the circuit: Input signal: 50-100 mV (It's the output of my iphone's microphone) 2 W - 4 ohms speaker There ...
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1answer
131 views

Removing switching artifacts from a commercial audio amplifier

I got an audio amplifier but I have problems with it. How can I remove switching noise (artifact) from the output of a Behringer iNUKE NU1000 Power Amplifier audio amplifier? I got from ...
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1answer
43 views

Debugging a SA 90.4 800W class-D audio amplifier

I am using a Re-audio SA 90.4 800W 4-channel class D audio amplifier (https://www.amazon.com/REAudio-SA90-4-4-Channel-Digital-Amplifier/dp/B00RE9EO7K) for some underwater piezoacoustics experiment. ...
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2answers
340 views

Bluetooth receiver combining differential outputs to single ended (LR, N) to one (main) secondary amplifier

Hello I am new to this forum recently purchased a CSR8645 Bluetooth Module I have a Sony MHC GX Music system with AUX/MD Video Audio input (Left Right Ground). But in my CSR8645 ...
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2answers
78 views

High-Z input in audio interface

In audio interfaces (e.g. USB) you often find one input that can handle XLR and jack. The jack input is usually used for an electric guitar input. For that, there is a "High-Z" switch to it. ...
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3answers
932 views

Reduced gain with ground loop isolation with car aux head unit

How to suppress ground loop hum without reducing audio gain? I added an aux input to my car's factory head unit by soldering wires onto pin 4 (right channel) and pin 33 (left channel) of the M62490FP ...
1
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1answer
107 views

lowpass filter question

I tried two solutions for a lowpass filter: Fig.1 - Normal RC lowpass with cutoff range of about 30-300hz according to the frequency cutoff formula. Fig.2 - Acoustically, this is closer to what I was ...
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0answers
52 views

Need help with simulating a 3-channel LED color organ in MULTISIM

I have been trying to simulate a LED colour organ in MULTISIM (literally) for hours. I don't understand why is it not working. My end goal is to get to simulate this on MULTISIM. Here's the circuit I'...
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2answers
34 views

FFT Frequency Bin - Impact on Energy Totals

If I reduce the number of samples used for an FFT (increasing the width of the frequency bins), is it correct to say that the energy in two bins with smaller frequency bins (eg. 10kHz-20kHz and 20kHz-...
6
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1answer
128 views

Would my Audio LED display circuit work?

Would this circuit work? It's supposed to display the frequencies of the audio signal connected using LEDs by driving them with an LM358 Op-Amp. Edit: fixed the reverse polarity of U7 Edit 2: I made a ...
0
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1answer
628 views

pam8403 using low wattage speaker

I am using the output of usb sound card as an input to PAM8403 ic with specs from datasheet. However i am using 4 ohm 0.5 W speaker. So i have tried testing with that and it works but sometimes with ...
2
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0answers
39 views

How to connect 5 colored wire headphone to 3.5 TRS jack?

I have a somictone headphone and I want to repair its headphone jack, It contains five colored wires. Here are the wire and TRS jack. Please give me a feedback Can you please tell me how to wire this?...
0
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1answer
42 views

Choosing an input signal based on whether a driver signal is floating

I have three inputs: an analog microphone signal (M+), a push-to-talk (PTT) signal, and a ground (G). The PTT signal is connected to G when the button is depressed and M+ should be carried, and is ...
0
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1answer
29 views

Stepping down/up center tapped transformer

I've got a Hifi setup to repair where the power amplifier died. I want to replace it with a different one. There is a center tapped transformer that provided +-35 volts DC for the original amplifier. ...
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2answers
1k views

What is the purpose of the capacitor in this transformer circuit?

I a audio DAC output stage I have seen the following circuit. It's function is to convert an balanced signal to an unbalanced signal. IN+ and IN- are differential outputs that are biased at 2.5V. ...
2
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1answer
168 views

CSR8645 3.2 bluetooth module audio output merge negative pins

I want to use this module with my car aux in which is has 3.5mm 3 pole jack. This module has separate negative pins as LN and RN. I need to merge and connect these pins to aux in common negative pin.
4
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1answer
6k views

Calculating impedance in a two-way speaker crossover

I'm trying to come up with a basic two-way crossover for a speaker I'm building out of scrap. (Working with what I've got - no new parts.) My amp handles 8-16 ohms. Here's what I've come up with for ...
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1answer
97 views

How to send this signal to a mixer?

I have the receiver which works when I wire a Hifi on the output. But when I try to send the signal to the port 2/3 of the following mixer then I don't have any signal anymore. I guess I need to ...
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0answers
60 views

Still audible noise after using a DC DC isolator

My setup consists of a DSP board with the ADAU1701 chip on it. Signals will come from my phone through an AUX-cable to the DSP. After processing the signals with the DSP they will be converted through ...
0
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0answers
64 views

How can I identify these capacitors?

Can someone please help me identify these? I think they are capacitors. I have no background in electrical engineering. Just trying to learn this stuff as a hobby. This came out of an audio amplifier ...
2
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2answers
74 views

Finding replacement PNP transistors

Hello and I apologise if my first question is rather basic as I am new to electronics. I have started to repair vintage amplifiers and have found transistors that I need to replace are no longer ...
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3answers
93 views

Why does attaching the case to the PCB ground plane cause the audio to cut out on my cassette player?

I bought a NIB (new in box) cassette recorder on eBay recently but have had problems with the audio from the start. The issue was that touching the dials could cause the audio to crackle, go quiet, or ...

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