Designing Legendary Gear with Paul Wolff June 22, 2017 16:42

Paul Wolff has designed more legendary pieces of gear than most of us have used. In his years with API alone, Paul designed the 550B EQ, 512 and 3124 mic preamps, Legacy console, and 2500 compressor. He was recently honored by NAMM TEC hall of fame for inventing the Lunchbox and 500-series format, which he helped turned into a cottage industry.

I was honored to have Paul on the podcast to discuss console design and how he's seen the industry change in the last 40 years.

Just a few of the things we discussed:

  • The origins of the 500-series
  • How Steve Perry became the first customer of the Lunchbox
  • The uphill battle to make gear that’s authentic to the API sound
  • What happened in 1978 to change the sound of most audio equipment
  • Paul's opinion that cloners "should be burned to death”

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Some Notes on API Jargon

As much as I try to keep our podcasts fairly jargon-free, I was guilty of using a lot of API model numbers without explanation this episode. These are:

  • 550A: Late 60's, 3-band EQ
  • 2520: The discrete operational amplifier (DOA, or "opamp") that's at the heart of most API designs
  • 2488: Early 70's console
  • 512: 500-series mic preamp designed by Paul
  • 312: 60's mic preamp
  • 3124: A 4-channel 312 designed by Paul
  • 2503: The output transformer in most API gear
  • 2500: Bus compressor designed by Paul


Analog Synth DIY with Abby Echiverri April 27, 2017 16:21

I've often fantasized about building a huge analog synth. But besides the obstacles of cost and not having a spare room in my house for it, I've always found the DIY synth world to be a bit intimidating.

In this podcast, synth wizard Abby Echiverri walks me through the basics, such as:

Is it feasible to build your own synth?

How much should I budget?

What are the basic modules I need to build?

Abby is a composer, DJ, DIYer, and audio gear designer. I caught up with her when she was on the road as the synth/keyboard tech for Soulwax.

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Chassis Design with Jon Erickson February 16, 2017 12:35

We audio nerds love to talk about particular parts and circuitry—transformers, op-amps, discrete vs integrated, passive vs active, etc—but we rarely discuss the biggest part and the one we actually interface with the most: the chassis.

In this episode of our resurrected podcast, I talk to Jon Erickson about the ins and outs of chassis design and manufacturing.

Jon Erickson has been involved with some of the most delicious-looking audio gear on the market: the A-Designs Pacifica preamp, JHS Pedals' line of 500-series modules, and his flagship Tonecraft 363 DI/preamp.

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"Explain Like I'm 5": Filters January 29, 2015 14:32 3 Comments

How do filters work?

As audio engineers, we use filters every day. We're all intimately familiar with high-pass, low-pass, band-pass, shelf, etc. filters. But how do they actually work in analog gear?

The basic operating principles of analog filters are actually very simple. In this quick (10 minute) podcast, Peterson and Chris explain the very basics of high-pass and low-pass filters so that any 5-year-old could understand.

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View the circuits we discussed in the podcast on Upverter:

“Explain Like I’m 5″: Audio Levels December 11, 2014 20:22 8 Comments

What's the difference between "pro" and "consumer" line levels?

Is it ok to plug an instrument into a line level input?

What's the difference between peak and RMS levels?

In the long-awaited return of our "Explain Like I'm 5" podcast series, Peterson and new DIYRE team member, Chris, explain the basics of audio levels.

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Topics discussed:
  • Can you damage equipment by plugging the wrong thing in?
  • In analog audio Volume = Voltage
  • The difference between peak and RMS volume
  • RMS is a way of measuring AC as if it were DC
  • The most common levels you'll encounter in the studio:
    • +4dBu, pro line level (1.22V)
    • -10dBV, consumer line level (.316V)
    • Mic level
    • Instrument level
  • Tangent: why are microphone output levels so low?
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Talking Tubes with DW Fearn August 26, 2014 12:07 1 Comment

DW Fearn knows tubes. Since he rediscovered the sound of tubes in 1991, DW (Doug) has crafted a legendary line of all-tube, all-red-front-paneled recording gear. In April I had the pleasure of visiting Doug at his home and workshop outside Philadelphia. Doug and I sat down on either side of a ribbon microphone and had a great conversation about tubes, electronics, and sound. During our conversation Doug tells the story of how he returned to tubes after decades of operating an all sold-state studio, and outlines the theory behind why tubes and transistors sound different in a clear and straightforward way. DW Fearn

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Topics discussed:

  • How Doug pieced together his first console from standalone amplifiers
  • What happened when he replaced that tube gear with a solid-state console
  • "We couldn't admit that it didn't sound good, so we just got used to it."
  • How a demo tape from college in 1966 led him back to building tube amps
  • "We didn't listen to recorded music in my household... live music was what I was exposed to. So when the time came to build a mic preamp, that's the sound I had in my mind."
  • Tubes vs transistors: why it's all about headroom
  • Even vs odd harmonics and how they relate to tubes vs transistors
  • "The less you torture it, the better it's going to sound. So you keep the signal path as simple as possible."
  • What Doug's new product design process looks like
  • The one equalizer that knocked DW Fearn out
  • DW Fearn refuses to wrestle a piece of gear into existence
Many thanks to Doug for having me out to his home and sharing his knowledge so freely. Thank you also to Paul K of Firehouse Recording for connecting us. You can learn more about DW Fearn gear at DWFearn.com.

"Explain Like I'm 5": Impedance July 18, 2013 16:20 10 Comments

When I sent out the newsletter announcing the last "Explain Like I'm 5 Podcast," I asked which audio topics you wanted to hear explained to a 5-year-old. As as result I now have a list of over 25 topics for future shows! But the response I got the most was "impedance."

One reader even taunted me: "Haha, explain impedance like I'm five..good luck with that ;)" Challenge accepted, buddy!

Impedance is one of those audio concepts that comes up at almost every recording session or live sound gig, even if you're not aware of it. Grasping the basics of input and output impedance can make you aware of potential problems before they happen, and help you problem solve more quickly and confidently. And the truth is that the fundamentals of impedance are simple enough that you can learn them from a 15-minute podcast.

In today's ELI5 podcast, I begin with a discussion of acoustics before moving to electronics to show you that you already know more about impedance than you probably think. I go on to cover exactly what input/output impedance specs mean, illustrate the concept of impedance with examples from the studio, and explain what impedance mis-matches can do to your sound.

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Do you understand impedance now? How easy was the podcast to understand? Is there any other topic you'd like to hear explained as if to a 5-year-old? I welcome your feedback in the comments.

"Explain Like I'm 5": Balanced vs. Unbalanced Connections July 11, 2013 12:30 8 Comments

This podcast marks the first of a new series in which I attempt to explain complex audio subjects so that a 5-year-old could understand them.

In this first "Explain Like I'm 5" podcast, I tackle the important subject of balancing. What is the difference between balanced and unbalanced connections? How does balancing work? Why do we need balanced connections?

In less than 15 minutes, I answer these questions the way I wish someone had for me: assuming no electronics knowledge, sticking to the basics, and using only terminology that a musician would understand.

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In order, I discuss:

  • What are balanced and unbalanced connections?
  • How can I identify the difference?
  • Why are there these two types of connections in the studio?
  • How does balancing reduce noise?
  • What is Common Mode Rejection Ratio (CMRR)?
  • If balanced connections are so great, why isn't everything balanced?

Mic Preamps and Surface-Mount Parts with Expat Audio March 14, 2013 14:15 2 Comments

In this month's DIY podcast, I talk to Dafydd Roche of Expat Audio about their new Eden Mic Preamp.

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Dafydd and I get into some good stuff about mic preamp and general audio design, including:

  • The difference between surface mount (SMD/SMT) and through hole components in terms of sound and performance.
  • Are SMDs good for audio? Should we audio folks resist industry's march toward all surface-mount parts?
  • The concept of "parasitics" in audio electronics design and when their effects can be critical.
  • Dafydd gives us a guided tour of the Eden circuit from the input to output jacks--a great way to get a grasp on the basics of mic preamp design.

"Everything You Always Wanted to Know About Audio Electronics..." Part 2 December 31, 2012 12:42 2 Comments

Our resident electronics expert, Duncan Gray, is back to answer your audio electronics questions! Duncan and I recorded two hours of answers last week to the questions you asked in the original "Everything You Always Wanted to Know About Audio Electronics..." post.

So to spare you the tedium of digging through 120 minutes of audio to find the answer to your questions, we've split our conversation up into smaller, more easily digestible podcast. Stick with us until the 33 minute mark, where we answer my favorite question so far that gets to the heart of the amazing relationship between audio and analog electronics.

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In today's 45 minute segment we cover:

  • "What troubleshooting process do you recommend when your PCB-based project isn’t working?"
  • "What audible impact does input/output impedance have on the connected equipment. The effect it has upon the amount of voltage transferred is clear, however a more comprehensive explanation on how impedance can alter the sound of interfaced equipment would be hugely appreciated."
    • When impedance can be negligible and when it can have a huge impact on sound.
  • "Capacitors have been causing me headaches for a while now. In pedals for guitars, tone circuits for guitars, audio paths for pre’s, and so on, it always seems like folks go the extra mile to use film caps. Why? Isn’t a cap a cap a cap? Putting aside electrolytics for the moment, and voltage limits, why would anyone use one style (ceramic, mica, polyester, polypropylene) over another for audio purposes?"
    • Why Duncan would avoid ceramic caps in the signal path "like the plague."
    • Duncan ranks types of film capacitors in terms of their suitability to audio.
  • "What parts are most/least to susceptible to heat damage from soldering?
    • Using a hemostat to protect your components while soldering.
    • Straight 5" Hemostat (Amazon affiliate link that benefits DIYRE.)
  • "What do you think the top five safety rules are when building audio gear , whether tube or solid-state?"
    • Which voltages are dangerous? Which are fatal?
    • How to protect yourself from the circuit, and how to protect the circuit from you.
  • "Can you clarify and explain the correlation between audio frequencies & amplitude, and their electrical counterparts current, voltage, and resistance… In other words what does a change in resistance, current, or voltage do to sound waves."
    • The "magic of math": how sound and analog electronics are deeply analogous.
    • Sound and AC voltage: same concepts, different medium
    • Using the concept of "silence" to better understand electrical "ground."

Is Open Source the Way Forward for DIY Audio? November 14, 2012 13:33 5 Comments

DIY audio folks like to share--that's what makes us a community. My kits and the DIY Project Directory are possible because others have shared their research, schematics, designs, etc. without any legal limitations. In turn, I document my projects so that anyone who cares to can learn from, tweak, or improve upon them. So, while the greater audio world remains largely closed, with patents, secrecy, and lawyers protecting intellectual property, our little DIY corner is very much an "open source" environment. But unlike explicitly open-source communities such as Wikipedia or GitHub, our openness is not formalized into licenses or explicitly agreed upon. In podcast #5 I talk Eric Jennings of Pinocc.io, an open-source, wireless hardware platform, about how an open source approach might look for the DIY audio community. Topics discussed include:
  • Is openness a viable way forward for the DIY audio world?
  • What exactly does open source mean for a hardware-based industry?
  • Does open source encourage cloners and copycats?
  • How can audio designers protect their work without patents?
Download the mp3 or subscribe via iTunes.

Being a DIYer, Studio Owner, and Engineer with Marc Alan Goodman of Strange Weather Brooklyn June 22, 2012 16:22 3 Comments

One thing I often wondered when I first got into DIY was whether any "real" producers and engineers built their own gear. So I was thrilled to visit Marc Alan Goodman at his studio Strange Weather in Brooklyn to see his DIY gear and talk to him about how DIY fits into his career as a successful studio owner and engineer. We recorded some video of Marc's DIY gear which you can see below.

After my camera ran out of batteries, we sat down and chatted about lots of DIY stuff.

Download the MP3 file or listen on Subscribe to the podcast!

Topics covered:

  • Becoming your own studio tech
  • The ecstasy and agony of trying to do everything yourself
  • Marc's involvement in the Harrison Ford Filter project
  • Marc's thoughts on the LAZ EQN, Neve-style EQ (of which he built 16!)
  • How DIY is as old as the profession of audio engineering
  • DIY: business or hobby?
  • Electricity as the true medium of a recording engineer
  • The vintage U87 project (of which he built 3!)

"Everything You Always Wanted to Know About Audio Electronics" Answers Podcast! (pt. 1) June 11, 2012 11:13 9 Comments

Last week, I put out the call for you to ask "Everything you always wanted to know about audio electronics, but were afraid to ask." The response was awesome, and a tad overwhelming: almost 50 questions! I want to sincerely thank all of you who posed questions, we got some great stuff. On Saturday our volunteer expert, Duncan Gray, joined me to answer your questions podcast style.

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Here's what we covered in chronological order:

  • How Duncan got into audio electronics (as usual, it involved breaking something)
  • Circuit talk:
    • What does class-A mean? Why is it desirable?
    • How do I measure the total current draw of modules in a 51x rack?
    • How do I choose the right power supply for a given DIY project?
    • What's the difference between an LC and RC filter?
    • What happens to the Q, or bandwidth, in a swinging input EQ topology?
    • What's the simplest way electronically to make a noise?
    • Why do parts of a circuit go to ground?
    • How should I ground inside the box?
    • What is star grounding?
  • Coloration talk:
    • Is there really a difference between NOS and new transistors?
    • How do you know if a device needs recapping?
    • Discrete vs. monolithic opamps?
    • How close can we get to replicating vintage gear?
    • What does a good preamp do that I can't just do in post production?
  • How do I get my foot in the door doing audio design?
  • The incredible learning resources at HyperPhysics
Again, many thanks to Duncan and those who asked questions. Stay tuned for pt. 2, when we'll talk about troubleshooting, safety, reference levels, and impedance.

What Makes API Gear Sound So Good? With Jeff Steiger of CAPI May 12, 2012 17:30 9 Comments

Jeff Steiger of CAPI and I get nerdy about various vintage audio and DIY topics, including:

  • Why create a company dedicated to vintage API gear? Why not Neve, SSL, etc.?
  • Will we ever see ClassicAPI kits in a 1RU rack format, instead of 500-series?
  • Why does old API gear sound so good when it's specs are so bad?
  • The sonically stunning Gar2520 opamp
  • Jeff's new, two-stage preamp design, the VP28
  • How Jeff tried to cram a full API console strip into one 500-series slot.
  • "Inventory management is a bitch."
  • How DIY gear is beginning to penetrate the big-budget recording world.
  • Are we seeing a return to the early days of recording when many engineers built their own custom gear?
Download the mp3 file or listen on iTunes . Thanks for listening. If you enjoyed the show, subscribe to the podcast!

DIY Condenser Microphones with Scott Helmke May 5, 2012 13:28 8 Comments

Today, I discuss the ins and outs of making your own condenser microphones with Scott Helmke, creator of the popular Alice Microphone project. Scott walks us through how he designed the Alice microphone, including some practical tips for making your own mic bodies and headbaskets. Topics discussed:
  • How Scott developed the Alice mic
  • The brilliant Mic Builders Yahoo group.
  • The Transound TBS-165A condenser capsule
  • What happened when Scott swapped electrolytic for film capacitors in the Alice circuit.
  • Tips for DIY mic bodies and headbaskets. The McMaster-Carr store is your friend.
  • What to look for in a headbasket mesh material.
  • "Somewhere between sculpture and audio."
  • Scott's most recent project: a linear microphone array for piano.