Questions tagged [audio]

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

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88 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
121 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
155 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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50 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
109 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
94 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
84 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
71 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
168 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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71 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
88 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
50 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
90 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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97 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 ...
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1answer
248 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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1answer
65 views

Identify components in an audio circuit schematic

In the attached image you can see a circuit part of a commercial audio amplifier. I'm trying to determine what kind of component is R-CH and what role it plays in ...
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0answers
68 views

ESP-07S / ESP8266 I2S audio interface with audio codec IC (audio input + output mono)

I have never dealt with digital audio interface like I2S. I want to use ESP-07S / ESP8266 audio interfaces as digital audio I/O (for mic + speaker). ESP-07 has two I2S interfaces: 3-wire audio input ...
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1answer
48 views

BJT reverse base-emitter voltage 1 Volts?

Using the multimeter diode setting in a powered down circuit, on the TR6 transistor (BC548), the forward B-E and B-C voltages are ~0.7 V, reverse B-C is OL but reverse B-E is 1.08V. Does this mean the ...
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0answers
53 views

Speaker and player on same 5V charger crackles but not with two separate chargers

I am using a Samsung mobile phone connected to an external speaker (connected via a standard audio cable with jack connectors). Audio is playing fine when I use two Samsung-branded 5V-DC chargers, ...
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1answer
65 views

Measuring BJT voltages in circuit?

Using a multimeter's diode setting I see that both the base-emitter and base-collector voltages of a transistor in a powered down circuit are 0.67Vm, while reversing the probes shows OL. Voltage ...
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1answer
75 views

Sony TA-1630 baffling me [closed]

I'm new to this forum. I have a TA-1630 that is truly baffling me. I know that some of you have had experience of this amplifier or a similar model, and wondering if you can offer some experience/...
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2answers
58 views

Protecting an ADC from negative voltage: Is it better use diodes OR to offset voltage?

I'm working on a simple guitar amplifier and reader with Arduino. The Arduino will use this input to find the amplitude and frequency of the input signal. I'm getting confused about how the ADC ...
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1answer
58 views

How can I calculate low and high frequency in my circuit?

How can I calculate low and high frequency in my circuit? I have used an 8-ohm speaker.
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1answer
44 views

Protect MOSFET gates in audio amplifier

I've made an amplifier from a circuit I found on the internet (below, link). I made it more or less exactly as described (same components, big heat sinks) and it seems to work great (can run at a loud ...
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1answer
120 views

Cathode bypass capacitor value in a Fender 5F1 Champ-style amplifier

I am building a 5F1 Champ-style amplifier and I am wondering about what value of capacitor to strap to the cathode resistor? I have seen suggestions of 22 uF and 25 uF and I am not sure what value I ...
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1answer
58 views

Characterising an Audio Isolation Transformer

Rummaging around the junkbox in an effort to find a 600:600 ohm audio isolation transformer, I found a possible candidate rescued from a store closure some time back. It's basically a cheap, low ...
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20 views

Accelerometer signal to audio signal

I have a accelerometer (ILS - MPU9250) and a woojer vest. The woojer vest is a device that shakes based on audio input. (simple line in with jack) What I would like to do, is to put this ...
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1answer
457 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
103 views

Wien Bridge Oscillator using OpAmp(LM386) works in simulation, but doesn't work in Breadboard?

This is a simulation of the circuit in multisim. It is a Wien bridge oscillator circuit, tuned at 1844Hz. I am mostly interested in generating sound of that frequency. It seems to work here in ...
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1answer
187 views

Trying to control vintage amplifier (TEAC A-H500) with Raspberry Pi - what's the communication protocol? 8-bit bus?

I'm trying to control my vintage amplifier from Raspberry Pi - I want to create a nice little Spotify streamer that on playback start will automatically turn on the amplifier and set the input ...
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0answers
45 views

Common ground for subwoofer-out

I have a Sony Sony DSX-A110u which is a car stereo having 4*55W Speaker out and a Sub-woofer out. The subwoofer-out port it a female RCA jack. which looks like this - I am using the sub-woofer out ...
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2answers
121 views

Is a 2N3906 an appropriate replacement for a BC158(B) in audio amp circuit?

On a long but educational process repairing a vintage German stereo. I have identified a failed (shorted) PNP transistor in the power amp section. (Schematic with highlight is below.) The part on the ...
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2answers
104 views

MOSFET based audio switch generates thumping sound

I need to switch on and off an audio signal without clicking or thumping. I have tried the below circuit that I designed and simulated in LTspice, but it generates a thumping sound when I wire it up ...
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230 views

Audio: Digital Potentiometer is Noisy Compared to Analog Potentiometer

I am building an A/V switch that I would like to have a headphone output with adjustable volume, controlled by a microcontroller. As a test, I connected an audio source to a potentiometer (input to a, ...
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1answer
102 views

'true' balanced audio?

I was working on the below circuit, to create a balanced audio output. But have been told this creates a differential audio output, not a 'true' balanced audio output. "A true balanced output would ...
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0answers
40 views

PLL for Audio Frequency VCO using R divider

I'm attempting to design a PLL for an analog, audio frequency VCO, but I've run into a conceptual problem. I can't reasonably use a divider in the feedback path. My reference frequency would ...
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2answers
211 views

Trying to understand this Class D amp (using IR2113) circuit

I understand the concept of the Class D amp and this circuit, but in this particular case there is one part I just don't get. What I don't understand is how the low side of the signal should work at ...
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0answers
73 views

Mixing Symfonisk high/low-mid output channels

So i've been messing with this issue for a couple of months and it's just that my electronics knowledge isn't reaching far enough. I have a Symfonisk speaker by Ikea, which outputs a low and high/mid ...
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2answers
310 views

balanced to unbalanced audio switch

I have an audio source input, that I am putting through the circuit below to create a balanced audio signal. There will be one of these for each channel, left and right. I have been asked to provide ...
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1answer
58 views

Output voltage of Class B Amplifier with global negative feedback

For the following schematic on the non-inverting input is applied a sine wave. Shouldn't be the output on R19 0.9 out of the input voltage, by using a voltage divider between R31 and R19. From my ...
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1answer
89 views

A general purpose way to connect cellphone line out to a microcontroller ADC

I have looked at many questions with similar titles but cone cover my query. Question: How can I protect an STM32 Cortex M4 series ADC input when measuring the AUX output voltage from typical ...
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0answers
35 views

Summing Audio Channels

I’m trying to sum my car stereo output. Factory output has bass on one output and mid and tweeter on another output giving me 2 channels for left and 2 channels for right. Ideally I’d like to sum ...
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0answers
44 views

Building a voltage controlled Wien-bridge RC oscillator

Out of curiosity I'm trying to design an audio frequency range oscillator that would produce a pure sine wave. I'm working in simscape (simulink - matlab) and here is the design I produced : The idea ...
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1answer
31 views

Why signal coming out of a Constant K filter takes 0.5ms to stabilize?

I made a simulation of an audio amplifier with an input signal of 200 microVolts. The question is why my filter does not deliver the desired output, which operates between 512 Hz and 2048 Hz. From ...
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1answer
47 views

Add aux input to Audio Amplifier circuit

I have bought a ready Audio Amplifier using TDA7498 chip and now I need some AUX input other than default one. Is there any circuit for this? https://www.st.com/en/audio-ics/tda7498.html https://...
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3answers
275 views

Why are one channel's transistors in a power amp getting much hotter than the other's?

(Context: I don't have a background in e.e., but getting better at basic bench work.) I'm repairing/recapping an early 70s German integrated stereo. The power amp output section has four large ...
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3answers
73 views

DC Analysis of this common emitter circuit

I'm learning about transistor configurations (particularly in relation to audio circuits) and am having difficulty analysing this fairly straightforward common emitter stage from the Instrument input ...
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1answer
86 views

Electromagnetically shield guitar pedal

I've built a few guitar pedals using op-amps, transistors, etc. (with supporting resistors & capacitors of course), and I've generally 3D printed the housing for the components for custom designs. ...
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1answer
102 views

What does this transistor, parallel to the audio output load, do?

I'm reverse-engineering the analog frontend of an SPDIF-to-analog converter. I'd like to increase its output level before feeding the audio (AUX) input of a Bluetooth speaker, which seems to amplify ...
2
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1answer
83 views

Channel separation on a 3.5mm audio jack

I read an article regarding the removal of the 3.5mm audio jacks on phones. It quoted this: ...

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