Questions tagged [audio]

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

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1answer
19 views

Electronic Circuit to Voltage control pan of stereo audio? (Modular Synth)

I'm considering making a Modular Synth module which would pan and modulate a stereo signal. So an electronic circuit to pan the audio from right to left, even allow audio signals crossing over, Left ...
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2answers
51 views

Identify whether PCB 1/4" audio jacks are balanced or unbalanced

I have a Fostex 2016 line mixer and was trying to see in the manual (https://www.fostexinternational.com/docs/tech_support/manuals.shtml) whether the 1/4" inputs and outputs are balanced (TRS) or ...
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1answer
243 views

Inverting Second Order Filter

I am working on an audio filter, and my goal is to filter out noise below 90Hz and 20kHz (the range of my speakers). I will have some nearby circuits running at 25 to 30kHz, so I have decided to go ...
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2answers
59 views

What are the pins on this jack connector?

I've bought a PJ-3053 audio jack connector. I purchased it under the impression that it would have a microphone connection, but when I put in a TRRS jack, take a multimeter and measure connections, ...
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1answer
372 views

Sound Chip Audio Amplification Circuit YM2612 + TDA1308

I've been working on a project for connecting a Yamaha YM2612 to an arduino and triggering sounds to be played from the chip. I'm having trouble on the audio part of the circuit. I've worked out a ...
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3answers
812 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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2answers
252 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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1answer
261 views

PCM1789 DAC direct connection to TPA6138A2 headphone amplifier?

Is it possible to directly connect PCM1789 DAC to TPA6138A2 headphone amplifier? According to datasheet PCM1789 output are differential outputs and the input of TPA6138A2 is also differential inputs. ...
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0answers
28 views

MCU with two I2S interface support [closed]

I am currently working on an audio recording project in which I am trying to record a mems microphone and save .wav file to the storage. I am looking for Microcontroller recommendations. The MCU ...
3
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1answer
202 views

Is volume controlled through a potentiometer?

Eletronics newbie here. I am building my first prototype (using an Arduino) that includes a volume knob. I want to know if volume is controlled by a potentiometer because I saw this video and it got ...
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2answers
86 views

Why did my meter read 6 volts dc in the speaker output of a car radio?

While probing a "live" car stereo pins, I also probed the speaker output pins but left the meter in dc volts mode and got a reading of 6v, wich I think is odd, as I asume the output should be ...
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1answer
55 views

Doorbell hack - remote unlock door

We need to use the audio output of a wireless doorbell to trigger a stable DC voltage which is going to keep switched a 3.3V DC relay as long as the audio output is present. The relay is supposed to ...
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1answer
56 views

Lower than expected power consumption from speaker drivers

I'm using two Visatron FRS 5X-8 Speakers in a project. The amplifier being used is a Dayton KAB-215. Powering the whole thing from my power supply at 12V, I see a current draw of ~50 mA even at full ...
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0answers
21 views

Diagnosing USB Power bank shut-off on load application

I'm trying to create a small bluetooth boombox-style speaker, but am having trouble powering the device from a USB battery bank. Fundamental Problem: The power bank "shuts off" as soon as the load is ...
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3answers
329 views

Filter/Regulator Layout for Processing Audio with Switching Supply

I have a question about switching supplies, regulators and filtering. I am working on a device powered by a +12V switching supply that has an analog circuit to process decent-quality (objective, I ...
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5answers
83 views

emitter follower oscillation cured by adding base input resistor?

I made a simple emitter follower headphone amp using fairly high speed BJT- 2SC5994. Vcc 16V R1- 10K R2- 40k RE- 100 load - 300 ohm After powering up there it was clear there was serious issue, ...
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0answers
32 views

feasibility of transmitting uncompressed 16-bit PCM audio through bluetooth

I wonder about the feasibility of this idea, and whether this is something worth doing more research on. I am trying to send 16-bit 16 kHz single channel microphone audio via bluetooth, from one ...
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1answer
268 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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4answers
22k views

MCLK in I2S audio protocol

I am working with the I2S audio protocol in one of my projects and I'd like to use it in one of my final projects for a class of mine. Quite honestly though, I don't entirely understand the MCLK line....
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3answers
637 views

Noisy BTL Audio Amplifier Circuit

I designed and breadboarded a simple audio amplifier circuit and when I play audio through the speaker, it is pretty noisy and very quiet. The +5V is being supplied from a USB port. I'm still probing ...
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4answers
163 views

Is it possible to sweep 20 Hz to 20 kHz with one potentiometer?

I'm designing a resonant filter based on a state variable filter topology with sweepable frequency and variable resonance. The filter is designed to sweep from roughly 20 Hz up to 20 kHz (50 kohm ...
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1answer
247 views

Metal enclosure grounding for audio project

Fellow engineers, For various reasons I picked extruded aluminium enclosure for my current audio related project. All exposed metal connector chassis are connected to earth, which then goes to ground ...
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3answers
6k views

Audio Balance Control

I've been trying to create a balance control circuit for two audio channels. I'm finding it extremely difficult. I'm very adamant about a single knob controlling both the left and right balance while ...
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3answers
121 views

A TDA2822M earphone driving problem (Hot earphone)

Recently I built a circuit to drive loudspeaker and earphone. The circuit was the same as the reference design (Fig. 1 of Page 4) of datasheet. It works fine with 8 ohm loudspeaker but makes earphone ...
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2answers
161 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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0answers
54 views

Is it possible to make a ±3.3 power supply from 9V battery?

I am trying to make a little audio amplifier with a ±3.3V power supply I and would like to power it with a 9V battery. Is there a solution to this? simulate this circuit – Schematic created ...
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2answers
312 views

BA3121: Ground loop supression is great however very thin audio quality

Recently I bought a couple of BA3121s to fight the annoying ground loop problems when using several/separated modules (MCUs, BlueTooth, USB etc) in class-d amplifier audio projects and all the modules ...
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2answers
41 views

Removing the load of an AC signal to a DC signal

simulate this circuit – Schematic created using CircuitLab I built this circuit to visualize music with LED's using a full-bridge rectifier I got from a vacuum(meant for 120VAC to 120VDC, with ...
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1answer
74 views

Miller compensation capacitor sizing

How can I size the circled capacitor in order to get rid of the peaking? Is there some formula? Cheers
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4answers
6k views

Transfering data using ultrasound

Yamaha InfoSound and ShopKick application use technologies that allow to transfer data using ultrasound. That is playing an inaudible signal (>18kHz) that can be picked up by modern mobile phones (iOS,...
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0answers
33 views

How to transmit the data from the buffer filled with ADC values through DMA on STM32F7

I am currently trying to a sample a signal between 25-40kHz with three microphones to calculate the time difference. I'm having difficulites understanding what to do after the ADC is activated and ...
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1answer
95 views

Negative loop gain?

I was dimensioning the CE capacitor. To do that I was looking at some formulas seen in class. The formula (freq_C=1/(2*piReqC)) involves the knowledge of the loop gain (open loop gain*beta). It ...
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1answer
74 views

Why is total harmonic distortion defined in the following manner?

So the total harmonic distortion is defined as $$THD = \sqrt{\frac{V_{2}^2 + V_{3}^2 + V_{4}^2...+V_{n}^2}{V_{1}^2}}$$ which means Total harmonic distortion is defined as the square root of the ...
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2answers
262 views

Audio Transformer Selection

I have a line-level audio output stage with an output impedance between 100-600 Ohms and an input stage with an input impedance of 10-20kOhms. I am looking to use an isolation transformer to connect ...
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2answers
63 views

Understanding purpose of a resistor in reference schematic TIDU034

Gents, I'm analyzing this schematic, but do not understand couple of things. I would be grateful if someone could explain in detail these questions: 1) R6 - shunt? What's the purpose of it? Under ...
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2answers
78 views

Noise on stereo summing circuit from LED's

I've been a tinkerer and hobbyist for 20 years now, but mostly in software. I've done my fair share of simple soldering (replaced controller ports on an original Xbox with actual USB ports, for ...
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3answers
745 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 ...
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0answers
22 views

What does “Power Off OOL” AT command mean for a Bluetooth module?

I am reading the datasheet for the OVC3860 Bluetooth module and one of the AT commands is 4.50 Power Off OOL #VX. The description from page 21 of the datasheet is below. [] What does OOL mean in ...
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1answer
35 views

Is it possible to make a “Sony CFS-201” cassette player/radio output sound from an external source?

I have an old 1989 (bought new well into the 1990s) "Sony CFS-201" cassette player/radio with a broken cassette mechanism. I'm trying to use it as a "dumb speaker" by hooking up an audio cable from my ...
0
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1answer
722 views

How to interface to a PDM audio source?

I hear about this technology, I read about it, I even see a bunch of MEMS microphones with PDM output. I can perfectly understand how it works (I have worked with DSP). However, I can't seem to ...
3
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1answer
482 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 (...
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2answers
181 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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1answer
112 views

Amplifier memory distortion application

I've found an article about memory distortion issues in audio analog amplifiers. Available for free here. The author uses in the last configuration a CFP differential input with a cascode of FET ...
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1answer
52 views

Shifting an audio signal from 0 - 4V to -2 - 2V

I'd like to transmit an audio signal over a digital radio and I figured out I'd need an op-amp in an inverting configuration on the transmitting side to turn a -2V to 2V signal into a 0-4V one. That ...
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0answers
57 views

0-5V Audio Signal with TL082

I am working on an Arduino project that requires me to be able to handle audio input from a 1/4" input jack, and it needs to be powered with just one 9V DC input. Since the Arduino cannot process ...
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0answers
110 views

Simple MM Phono Preamp Design

I'v found myself in need of a new preamp for my turntable (the one built into my power-amp went out with a bang and tripped the breaker!). I'm using a moving magnet type cartridge with output around ...
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3answers
1k views

Hobbyist: Is this a reasonable design for an audio amplifier? (very sketchy design)

I have always wanted to design and build my own audio amplifier. Is the following a reasonable design? The input stage takes in line level signals (say, up to +/-3 V, but typically more like 0.3 - 0....
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2answers
19k views

Single supply op-amp audio amplifier

I am trying to create an op-amp amplifier that would work from single 5V supply, and would be able to amplify -100mV to +100mV audio signal to around a 1V peak-peak or so. I've came across this ...
9
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1answer
1k views

How does this transistor (pre-)amplifier work?

The following circuit is part of a larger circuit and processes analog audio. The input comes from the top-right and the output is the rightmost terminal of the pot, which then feeds into a ...
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2answers
77 views

simple LM386 amplifier noise

I tried to make an audio amp based on LM386 but the output is noisy when the audio is playing. Here is my circuit schematic I built on a solderless protoboard: simulate this circuit – Schematic ...