Questions tagged [audio]

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

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84 views

How does the Yamaha DX7 digital analog converter work?

The Yamaha DX7 keyboard seems to have a quite sophisticated DAC and I wonder how it works. It is mostly specified as 12-bit DAC running at a sampling rate of 50kHz, but this doesn't tell the whole ...
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3answers
94 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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1answer
77 views

Problem with potentiometer in op-amp audio system design

I have a simple audio setup I am trying to build that consists of an op-amp board (OEP30Wx2), 2 speakers (Dayton Audio ND65-8), a steady 16V power supply (this op-amp requires 16V to drive 8 Ohm ...
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3answers
135 views

What's wrong with this audio amplifier and stereo to mono circuit?

The image below presents part of a schematic of an MP3 decoder (VS1003) with stereo -> mono conversion and audio amplifier to connect a speaker. The problem is that after assembling the PCB barely ...
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2answers
107 views

Wiring for stereo mic using MAX9814

My goal is to test some algorithms for sound localization, so I connected two microphones (MAX9814 boards from adafruit) to my soundcard. In the future I want to use four channels. I wired them like ...
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1answer
51 views

How to scale audio signal from PCM data to a dB SPL value?

0 I've got a set with MEMS microphones that measure audio signals at ultrasonic frequencies. The MEMS microphones have a PDM output which is then converted into PCM (this is necessary to allow for a ...
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0answers
65 views

Transistor Noise A Concern In Emitter Follower

I'm looking at using a high voltage BJT as an emitter follower in a high voltage tube audio application (guitar amp). Unfortunately in the range of 200V, most BJTs are marketed as switching ...
2
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2answers
185 views

Can't find the datasheet of cheap Bluetooth audio reciever

The chip says JL AP24186-26A4, but I can't find datasheet anywhere. Everytime it takes me to dead end. If someone know about it then please help. Update: Found that it's Bluetooth 5.0 based audio ...
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2answers
77 views

What is the buzzing sound I hear via headphones when I touch my charging laptop?

I noticed that when I'm wearing my headphones, if I touch my laptop that is plugged in to an outlet and charging, I hear a slight buzzing sound. What is causing that? Should I be concerned?
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2answers
102 views

Help me interpret this audio jack schematic

I'm having trouble interpreting the following schematic: From this drawing: Adam Tech ASJ-99H-R-HT-T/R drawing I want to know: Are 5 and 6 normally open (open when there's no plug inserted), or ...
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1answer
84 views

I need help identifying this potentiometer

It is off of a Hifonics mono channel car audio amplifier. This is the back. It has 6 prongs and was removed from the gain spot on the amplifier:
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1answer
127 views

What FET can I substitute for PF5102 or J305? [closed]

I want to build this microphone: https://www.instructables.com/id/Modify-a-cheap-LDC-Condenser-microphone I am able to find all of the parts except for the FET. The schematic says to use PF5102, and ...
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3answers
824 views

Amplifier auto shutdown design

I'm building a Hifi amplifier and I wanted to design a circuit which switches off the power of the amp boards if no music is played for like half a minute. I built it on a demo board but it looks like ...
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2answers
133 views

Why are resistors necessary in a summing audio circuit?

I am researching DIY stereo audio mixers (2 input, 1 out) -- there's lots of info out there -- but all the passive solutions (e.g., DIY Multi-Input Audio) include resistors, and I don't understand why ...
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1answer
70 views

Accuracy when measuring THD with LT Spice for AB Audio Amp

I've designed and built my own AB class audio amplifier circuit. I designed it to have as low THD as possible, using LT Spice to run my simulations with the .four command, so I created a bunch of ...
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1answer
41 views

Help in understanding Audio line output stage

I was trying to understand the audio line output schematic shown below but couldn't make sense of it. This circuit comes after the output of an Audio DAC PCM1725, followed by an active 1st order low ...
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0answers
49 views

Questions regarding transistor audio amplifier circuit

I have a few concerns with the audio amplifier part of my circuit which I hope somebody can help me with... It's part of a larger circuit but the schematic below shows the parts of the circuit which I'...
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1answer
119 views

Rotary encoder causing ripple noise on digit potentiometer

I am using a rotary encoder to control the value of a digital potentiometer, specifically the MCP41HV51. I have a 9V supply feeding a 5V linear regulator. My logic supply for the digit pot is the 5V, ...
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1answer
42 views

Is there a connector that breaks the default circuit when a plug is connected? (e.g. cut off speaker when headphones are connected)

I want the normal path from a sound card to go to a speaker/internal mic, but when a headphones or mic (mic with PTT, hence 4-pole) is connected in a 3.5mm plug then I want to reroute there. Ideally I ...
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1answer
184 views

Creating a custom TRRS splitter for headphones and mic; how to handle the mic's TRS jack?

I want to create a TRRS splitter / joiner that can be used to combine two 3.5mm jacks, one for headphones and one for a microphone, into a single 3.5mm TRRS male jack. It'll use the CTIA standard so ...
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0answers
74 views

Automatic gain control circuit with dc offset

I have a circuit that takes a sine wave amplifies it a little bit but also adds a DC offset of 1.5V. It works perfectly no matter the input volume. Now that I am reworking everything it would be nice ...
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0answers
35 views

High pass filter that locks voltage at certain amount until frequency is reached

I have a sine wave that is biased at about 1.5V DC. I want to create a high pass filter that allows any frequency through greater than 4000Hz. Want I want my high pass filter to do is to be at 1.5V ...
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1answer
105 views

RC4558 vs LM741

I want to use RC4558 as a low pass filter for a subwoofer. But, because of the lockdown situation, I am unable to get one. I only have LM741 in my package. How can an LM741 IC replace a RC4558? I read ...
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0answers
107 views

Make audio signal go only one direction

I have a circuit in my car which emulates the protocol the radio uses to communicate with a CD changer. The goal of the emulator is basically to make the radio open up it's audio channels. The circuit ...
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4answers
2k views

75 Ohm Coaxial Cable Used On a 600 Ohm Output

I'm working on restoring an HP 211A square-wave generator and I'm looking to add a shielded cable to the 600 ohm output. I've got some spare 75 ohm RG59 cabling and I was wanting to know if using that ...
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1answer
89 views

How do I slowly short pins 2 and 3 of a phantom powered mic signal?

Shorting pins 2 and 3 of a microphone signal will mute it and is acceptable for when phantom power is present. I can do this with a regular switch, or a solid state relay. But is there a simple way to ...
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1answer
136 views

How can I emit a (loud) 25 kHz sound wave from a Raspberry Pi? [closed]

I am attempting to emit a 25 kHz ultrasonic square sound wave from my Raspberry Pi. I have used two different kinds of ultrasonic speakers: https://www.amazon.com/gp/prod uct/B00M2GHG66/ref=...
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1answer
67 views

Maximum DB of lm386 [closed]

What is the maximum Decibels that an LM386 chip, with its best wiring can go? I have recently wired the LM386 to a breadboard and have found the audio output to be only about 55 dBA SPL. Is that the ...
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1answer
57 views

Circuit to cut one audio input into another

I have a project I've been scratching my head over for a few days. I work a lot with 2-way radios and like to listen to music while I'm doing it. I wear an earpiece for the 2 way radio. I want to ...
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4answers
64 views

How to make an audio 5.1 switch?

I'd like to make a 5.1 audio switch to enable my 5.1 audio system (+mic+headphones) to be available for any of the 4 computers it can be connected to. So I guess I would have : INPUT : 4 (computers) ...
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1answer
49 views

Connecting Stereo Jack Socket

I have the following Stereo Jack Socket, but I think Its pin layout is different than the socket images available on the internet. Please show me how to connect this female socket to the circuit (L, R,...
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2answers
78 views

How to dial a phone number via DTMF tones?

I want to dial a phone number on a landline with DTMF tones generated by my phone. I tried soldering a 3.5mm audio jack to a phone cable and using my regular phone app, but nothing happened. In this ...
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2answers
68 views

PIC MCU: Reliably Capture and Measure Drum Transients with ADC

I'm seeking advice to help my circuit/code/mcu work more reliably and accurately. What I've got right now is almost there, but I'm just missing the know-how to get me consistent readings. I've tried ...
3
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5answers
276 views

understanding input impedance theory

The key question is, what is the best or right way to modify input impedance? I am a self-teaching novice at electronics. I'm using the LM386 as a learning platform. Signal input comes from a "...
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1answer
461 views

TDA2030 vs TDA2050 vs LM4440 [closed]

Which one of the three ICs you will suggest or most recommend to build an audio amplifier. I have checked the datasheets but still, I want to know how they perform in practice, which one sounds better ...
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2answers
82 views

Mono to stereo circuit only if one cable is plugged in

Im not sure how to phrase my question or what to google, but does anyone know how this feature is implemented (eg a simple example circuit): On some audio mixers, if only the left channel is plugged ...
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2answers
91 views

Suggestions for TDA2030 Audio Amplifier

Please suggest any ways to improve punch or bass of the sound for the following audio amplifier using TDA2030A. The sound output of the amplifier lacks some bass. Can I use TDA2050 to improve sound ...
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2answers
145 views

Noise in audio amplifier

I have built an audio amplifier using TDA2030. The amplifier works fine with very low noise, the input is given through 3.5mm jack of my phone. Everything works fine until I touch or pick up my metal ...
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0answers
36 views

Latching relay for audio switching

Previously I have switched line level audio using a Zettler AZ850P2 relay (Bistable Latching DPDT 5V 2-Coil, 1A). Currently, I am planning a somewhat more complex soulution allowing switching audio/...
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2answers
105 views

TL072 based circuit generates loud noise

This circuit, designed as a bass scream, keeps generating a low noise about the same loudness as the guitar signal on the output.
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1answer
73 views

Help with TDA2030A Amplifier circuit

I am designing an amplifier circuit using TDA2030A, but now I am stuck in providing power to the circuit. As mentioned in the datasheet, I copied single power supply circuit for my amp. But the ...
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0answers
68 views

I need help with making a ground loop noise isolator

I want to build a ground loop noise noise isolator for 3.5 mm audio jack. After some research online I found multiple circuit diagrams centered around using audio 1:1 transformers to isolate each ...
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1answer
68 views

Problem connecting to Arduino with USB and audio

I have a project which uses an Arduino to detect tones generated by a laptop. The Tone Detector (TD) circuit is a very simple LM567 implementation designed to detect 10kHz. The circuit is powered by ...
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1answer
118 views

Alternatives to op amps LM307N and TL071CN

I'am working on an amplifier/driver circuit for a spring reverb bank. The circuit is from the 90s, but still used: Accutronicsreverb Drive 1 Circuit My issues are the LM307N and the TL071CN. These ...
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0answers
60 views

Voltage rating of 3.5mm jack audio output

I am building an audio amplifier using TDA2030. I want to know what is voltage (RMS or peak-peak) rating of typical audio output from 3.5mm jack. I am doing a simulation in Proteus, and I am having ...
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3answers
84 views

How can I overcome the distortion using in this circuit by using same products as we see in picture ? Or we can use 2n700 series, 3906 and 3904 bjts

Or we can use 2n700 series, 3906 and 3904 bjts. My aim is 10W, gain 100-1000 (adjustable), 50hz-20khz amplifier by using this basic components.
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2answers
49 views

Audio ADC - grounding problem

I searched through the internet but couldn't find an answer to my question. Maybe I just don't know what to search for. I want to convert an audio signal coming from a stage box from analog to digital....
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1answer
89 views

Debugging the physical components in a circuit

What is the best approach to debug the physical components of a circuit that does not work? I set up a circuit for a simple audio player following this tutorial. However it simply does not work. The ...
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0answers
72 views

3W/6W audio amplifier using TDA2003

I am trying to build an amplifier circuit using TDA2003, I found a common type of circuit for this purpose in almost all the websites. I tried building it in Multisim and after some seconds of ...
0
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1answer
144 views

I2S audio interface - sync of MCLK and LRCLK signals

I plan to use IC AK4430, an I2S digital interface sound output chip, to be connecte to an ESP-07 Wifi module via 3 wires (BITclk, LRclk and DATA). But the IC also require an input signal that they ...

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