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  • Author Author: dychen
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Audio Tweaker's Wishlist - What do I need to build/maintain audio gear?

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Many makers and engineers got into engineering through audio. Whether it be building a guitar pedal or modding the power amp in your home theater, working with audio components is a fun way to use your engineering skills.

This wishlist presents some of the tools and parts you need for working with audio. Audio is a broad topic, so this wishlist is a general overview of analog audio components. We'll get specific in later articles.

Tools
For audio related building, here are some handy tools to have on your bench!

Oscilloscope
An oscilloscope is your best friend for audio work. They can be used to check frequency response, distortion characteristics, and everything other specification that is important to an audio signal.

Oscilloscope

Multicomp Pro Oscilloscope

Function Generator
Audio work is all about frequencies. A function generator sends different kinds of waves at different frequencies so you know if your build is responding the way you want it to.

 Function Generator

Multicomp Pro Function Generator

Multimeter
Multimeters are essential for every kind of electronics work; audio is no different.

Multimeter

Multicomp Pro Multimeter

Speaker Dummy Load
Since we can't use speakers for our testing, all that power needs someplace to go. A dummy load simulates a speaker in your circuit without blowing your head off with volume. A dummy load can be built with a high wattage resistor at the desired resistance, usually 4, 8, or 16 ohms for speakers.

Speaker Dummy Load

Vishay Dummy Load

Contact Cleaner
If you're repairing equipment that has scratchy pots, many times, a bottle of contact cleaner is all you need. Drip a little bit into the pot and exercise it; your noise issues will often disappear.

Contact Cleaner

Contact Cleaner  

Helping Hands
You've probably already got a nice soldering station, so we won't get into soldering equipment, but with any soldering project, because we don't have six arms ourselves, a set of helping hands is very valuable.

Helping Hands

Duratool Helping Hands

Components
Audio circuits use a wide variety of analog components to keep that audio sounding good.

Transistors
Transistors are typically used to amplify audio signals, and sometimes distort. Different types of transistors have different characteristics, whether they are BJT, MOSFET, JFET, or even silicon or germanium.

Transistor

Multicomp Pro Transistor

Potentiometers
If you're putting any kind of analog controls on your new creation, you'll likely need pots or faders.

Potentiometer

Bourns Potentiometer

Opamps
Opamps (operational amplifier) designed to amplify signals and there's a wide range, from large and discrete, like the vintage API 2520 (and its descendants), to surface mount. Opamp design has come a long way and newer opamps, like the AD797, boast near zero distortion and noise, although classic opamps like the TL072 and 5532 still offer great sounds in the right circuit.

Opamp

AD797 Opamp

Transformers
Transformers do a whole lot of things in an audio circuit; impedance matching, balancing, stepping up or down, etc. Because they only transmit audio signals, transformers also provide an important benefit: isolation.

Transformer

Hammond 119DA Transformer

Power Supply
Your opamps and transistors need to be powered, so chances are you'll need a good DC power supply. Op amps typically take somewhere in the range of +/-16V, while a discrete transistor based circuit might require a 24V supply. If you're making a microphone preamp that supplies phantom power, you'll need to supply 48V.

Power Supply

Delta 24V Power Supply

Connectors
To get your audio signal in and out of your circuit, you'll need connectors.

 

XLR Connector

Neutrik XLR Connector

Terminal connectors

Cliff 8-Way Spring Terminal

Speakers, Headphones, and Mic
Now the fun part! The most important tools for testing audio devices are your ears.  Speakers, speaker drivers, and headphones are the most important tools once you're ready to test your design. Fingers crossed that you don't get a blast of loud feedback when you flip the switch!

Trust powered speakers

Trust Speakers

Headphones

Koss UR20 Headphones


There are several different types of microphones – large diaphragm condensers, small diaphragm condensers, dynamics, ribbons, and more, all designed for specific purposes. We’ve selected a lavalier because it’s a tiny inexpensive mic that is convenient for testing on the bench.

Microphone

Pulse Lavalier Microphone

Parents

  • I'd have to say that audio is frequently a subjective topic with many opinions about what sounds good (or better) than something else. Alas, the concept of a home-theatre or Hi-Fi seems a bit outdated, like the TV. Rarely does the family (or neighbours) enjoy what I'm listening to, nor do I want to annoy them, and there are just so many situations where I'm just not in the one place either. It's hard to find something that everyone agrees on, but I've often gone with more personal audio equipment that has a sharper audio signature, more suited to critical listening tasks, than the consumer-centric bassy/boomy sound signature.

    Right now, when I'm at my computer desk, I have an Asus Xonar Essence STX driving a pair of Audio-Technica ATH-M50x headphones as my main listening device. Closed back headphones isolate the outside noise while not adding any additional noise like active noise cancelling headphones do. They may not be as sonically transparent as open-back headphones, but I didn't want the sound leakage to affect others around me either. The sound card's inbuilt headphone amp does a decent job of making the most of these too - there are swappable op-amps, but I haven't felt the need to switch at this time. The main thing is the high SNR and low distortion which ensures good sound. I do have the second output on the sound card hooked up to a set of TDK Tremor XA-80 nxt panel speakers, for use when I am alone in the house and want to move around.

    But more often than not, I'm listening around the house or on public transport. For that I rely on my Sennheiser PXC550 active noise cancelling headphones over Bluetooth. They're not as sharp as the M50x and the noise cancelling does add a bit of background hiss, but the noise cancelling makes up for this somewhat in noisy scenarios by letting me listen at comfortable, non-fatiguing volumes and hopefully preserve my hearing. I upgraded from a set of Audio-Technica ATH-ANC9s as they were wired and I eventually decided to "cut the cord" and go wireless. Another advantage is being able to charge the PXC550s rather than needing to swap an AAA cell.

    I find that I rarely ever use speakers for listening ... at all. But when I do need to record audio, I have a Zoom H4n and a Zoom H1 Handy Recorder to do on-site recordings to the internal SD/microSD card, or hooked up via USB as an audio interface. If I need something more directional, I do have some old USB Karaoke style microphones for the old "Singstar-like" games which actually doesn't do a bad job. I've been eyeing a proper microphone though - like a Rode NT1 USB or similar, but I do so little in the way of recording and my room is just too noisy to justify the investment.

    - Gough

  • in reply to Gough Lui

    Nice gear!  The Zoom recorders are nice. I have Tascam ones for location recording, but I think the Zoom ones have much, much better battery life...which is pretty important for location recording.

Comment Children
  • in reply to dychen

    I'm quite fond of the Zoom recorders, although the inputs on the H1 does have some noise if you crank the input gain all the way. It probably comes from the microSD spiky power consumption and the switching power supply as the recorder uses just 1xAA battery. But I easily get about 10-12h from a decent battery and the noise isn't a problem for most cases.

    The H4n Pro Black seems to be their latest ... probably should have saved up some more for that one as it's got more input flexibility and probably even better converters.

    - Gough