DIY-Central.com - Go Create something! - PCB Design, Electronics

Oscilloscopes are indispensable tools for anyone designing, manufacturing or repairing electronic equipment. In today’s fast-paced world, engineers need the best tools available to solve their measurement challenges quickly and accurately. As the eyes of the engineer, oscilloscopes are the key to meeting today’s demanding measurement challenges.

Tektronix presents the XYZs of Oscilloscopes. Learn about the different types of oscilloscopes, systems and controls, measurement, and how to operate an oscilloscope including measurement techniques.

Looking to save some money? Create your own cables! By spending a few dollars on jacks, shielded cables, solder and soldering iron, you can save a ton of money in cables.

For more money saving tips for your home studio, like building your own Neve preamps, SSL compressors, Yamaha "old-school" type preamps, MIDI controllers, check out my other projects.

Back to building your own cable...It's easy. Here are some step by step photos. 

At the bottom of this article, is a wiring guide for XLR to XLR, XLR to TRS, XLR to TS, and whatever combination you can think of.

On this guide, I'm wiring up an XLR cable.  First, we disassemble the cable by unscrewing the lock screw. Pull out the rubber plug (black thingy) and then you'll be able to push out the 3-pin connection assembly.




Since an XLR cable is a balanced cabel, we need a 3-wire cable. Also, make sure it is shielded to provide RF interference protection. 




Now, let's take a look at the XLR jack itself.  It's got 3 pins. Pin 1, 3 and 3. 

The convention is Pin 1 is the GROUND.
Pin 2 is the HOT (+) wire.
and Pin 3 is the COLD (-) wire.

Note: The COLD wire (-) is not the same as the GROUND wire. Don't short these two wires together!

Here's a closeup of the 3-pin assembly and you can see it's labeled for us. Great!  For this, I'm going to make my RED wire my HOT (+) wire and the WHITE wire as my COLD (-) wire.  (If you're wiring a headphone, the RED wire is usually designed for the RIGHT channel, and the WHITE wire for the LEFT channel)



Strip off a few millimeters of insulator, coat it with solder and solder it to the XLR jack terminals.



When you're done soldering the 3 wires, crimp the jack around the cable. This will provide support to the cable... i.e. when you yank off the jack, your wires wouldn't disconnect from your solder points.



Here, you can see the metal teeth crimped around the cable's jacket. Use a long-nose pliers to crimp it close. But don't crimp it too much that you mess up the cable.

Do the same procedure for the other end of the cable. This time using a Female XLR jack.  And here's our finished XLR cable.



If you need to DIY a different kind of cable, say a TRS jack or RCA, use the table below as a guide. This guide has been provided by Rane in their Technical Library section. Visit Rane website.

Credits: Rane

Visi the RANE website for more information about grounding, shielding, ground loops, etc.

Just a continuation of the saga of building my 1176 clone compressor/limiter. Click here for Part 1

Parts arrived a few days ago, and other than the audio input and output transformers and chassis, I think I have enough parts to build (2) units. Here are some pics...

First, we have the output LL5402 Lundahl transformer and the LL1540 input transformer. Made in Sweden.  These things are small.

I got most of the capacitors and the power transformer at digikey.com. They have good prices for these components.




The rest of the parts like the pots, resistors, and ceramic/mylar parts came from Mouser.com. It's a big pile!







I'll clear up my work area and maybe this Christmas break, I'll be able to start construction.  Oh yeah, need to order some 2u case from Par-Metal.com.  I only have spare 1u cases in my workshop at the moment.

We're ready to build the 1176!

I've seen the new Zoom H4 Handy Recorder. I think it's a neat little thing! And best of all, it's "cheap" at $299. Of course, "cheap" is a relative word, but compared to other gear out there, this seems to be one of the low priced new entry. It looks good too!

While reading the H4 specs, this caught my eye... "The H4 features 2 studio-quality electret condenser microphones configured in an X/Y pattern for true stereo recording."  The keyword here is "electret microphone." And the picture seems to confirm that it's really just an electret mic.

So I'm thinking, maybe I can DIY my own stereo mic.

I've used an electret microphone on a non-audio project. I made a sound-triggered flash sync for my Canon EOS30D camera. In this case, I just used the audio output from the mic to trigger an SCR, which then triggered the camera flash.

Can we used the same electret mic to create a good enough sounding stereo mic? I think we can.

So I begin adapting my sound-triggered flash sync and while doing some Googling around, I came across this product.
Stereo Super Ear Amplifier Kit

It's a kit made by Velleman and it uses 2 electret mics, and a headphone output jack. Hmmmm.... interesting. So I ordered a kit (hey, it's less than $10 so if it didn't work, it's not too much of a loss). You can use the link above to order your own kit.

The circuit is simple... the Left and Right channel is the same, so the operation of the circuit is identical. Basically, an electret condenser microphone is biased for operation using a single resistor and capacitor. The output of the microphone goes to a potentiometer which acts as the volume control. This is then amplified by the NE5532 opamp, which is then routed to a headphone jack. Since the whole circuit operates from a single supply voltage (4.5Volts), the opamp uses a virtual ground by the use of 2 resistors in it's input pin. This of course, means that each leg of the split power supply will be only Vcc/2, where Vcc=4.5Volts.

I built this kit in less than an hour... while watching TV. And construction isn't hard and it's very simple. So if you're ready to jump into this Electronics hobby and looking for your first audio project, why not try this stereo mic kit? It's only less than $10.

Here are some pics during construction... enjoy.



There are assembly instructions and schematics on the box. Very easy to follow.

The Art of Electronics
Price: $55.79

People have asked me what is a good book to read to start DIYing... On this page, I'll compile books that I have, read, or know will be good for the DIYer or electronics buff.

The following books are not expensive... the most expensive of the bunch is $55. But considering the knowledge you'll have (priceless), and the savings you'll realize when you build that super-duper preamp for a few hundred dollars rather than buying one and spending $1400, these books are a bargain.

These books link to Amazon.com. I'd appreciate it if you can buy your books by clicking on the links below :)

This site takes a lot of time, effort and money. My latest addition is a new bookstore with products and reviews from Amazon.com.  If you like this site, please consider buying books or stuff via my Amazon link. You'll get great prices and it won't cost you anything extra. In return, I get a little commission that I can use to pay for hosting of this site.

Check it out.  Buy from Amazon.com

It's that time of the year... here are some gift ideas for your home studio.

Furman PL8II Rackmount Power Conditioner with Lights
So you have thousands of dollars in gear and you're plugging it "naked" to your wall outlet or with a $5 Walmart power strip? I recommend you buy this power conditioner that will give you added protection to your gear. All your gear plugs to the back and you have a single switch to turn on all your gear. The lights are very handy too illuminating your rack gear so you can see what you're doing.



Korg MA-30 Metronome
Keeping time is important. And this little device from KORG packs a lot of sophisticated features at a small size. You can do rythms such as triplets and quadruplets with inner beats removed.

This is probably one of the best site on the internet for building guitar stompboxes and effects. Kits are available, along with ready-made PCBs. 

You can build Amps, Bass Effects, Boosters, Routers, Compressors, Distortion boxes, EQ Tone Control, Filters, Modulators and Echo, Noise Generators, Octave, Phase Shifters, Power Supplies, Reverbs, Tremolo Circuits, Wah Wah, and others.

Projects have cool names like Little Gem, Ruby Amp, Rangemaster, May Queen Booster, etc...

Schematics are available, along with soundclips, and photos of the finished project. I think everyone, even those with little or no electronics experience can build these projects because they are simple, safe (low voltage, 9V usually) and small. Of course, it's also cheap so if it didn't work out, it's no big loss.

PDF files are available with the board artwork, parts list and wiring diagram. So what are you waiting for? Start building! Go create something!

Here are some sample pics to get you started/excited. Okay... now go visit the site and go create something!
 

Moogheads, Tubeheads, VCOVandals, VCFFreaks, DCOOverlords... let's build some modular synths! Get your soldering irons hot, open up your browsers to Digikey and Mouser and your favorite surplus store because you'll be building some wicked synths, old  school style. Yup.. old school style, without PIC programming or embedded firmware that a bunch of codewarriors just programmed. No siree!... we're going to be pushing, bending, forcing electrons to do the work... not some silicon nerd that's just faking it.

You can buy ready-made units from here, pick and match what you need, wait 4 weeks, and then wait for Mr.Brown to deliver your packages. Then you'll be able to create sounds like this.

If you can't wait that long, or want the excitement of DIY, you can buy the ready-made PCBs, add a few parts and there you have it.  Look at all the stuff you can build.

This site is run by Ken Stone.

CV processors

• Analog Logic voltage processor
• Analog Shift Register
• Cascade Mixer
• C.V. Cluster
• C.V. Mega Mixer
• D.C. Mixer
• Joystick controller
• Matrix Mixer
• Modulo Magic
• Voltage controlled amplifier

  CV Generators

• Diatonic Converter
• Gate Sequencer CV Adapter
• Infinite Melody
• Pedal board/Mini Keyboard
• Psycho LFO
• Programmer/Sequencer
• Super Psycho Modulation source.
• Utility LFO.

  Clock/Gate/Trigger processors

• Burst Generator
• Gated Comparator
• Gate to Trigger Converter
• Gate Sequencer
• Master Divider
• Pulse Divider and Boolean Logic
• Quad Logic Gate
• Slope Detector
• Sub-oscillator/harmonic sequencer

  Signal Processors

• Bandpass Filter
• Bi-N-Tic Voltage controlled Filter/oscillator
• Cascade Mixer
• Delay Development Board
• Dome Filter
• Modulo Magic
• Real Ring Modulator
• Saw Pitch Shifter/Wave Multiplier
• Simple Wave Folder
• Steiner Voltage Controlled HP, LP & BP Filter
• Steiner Voltage Controlled HP, LP & BP Filter, Eurorack format.
• Sequential Switch
• Tube VCA and wave folder
• Wave Multiplier
• Voltage controlled divider
• Voltage controlled amplifier

  Signal Generators

• Chime Simulator
• Cynare (drum simulator)
• Digital Noise
• Drum Simulator
• V8 Engine Simulator
• VCO
• Wavetable for VCOs

  General and Accessories

• +/- 15 Volt Power Supply
• Display Adapter
• LED Driver
• Power Supply Delay
• Stomp Box Adapter (Use CGS modules as effects pedals)
• Stomp Box Adapter (Use effects pedals as modules)

  Digital Synth subsections

• D/A Converter
• Digitally Controlled Oscillator
• Keyboard Scanner sub-module
• Parallel port adapter

Schematics, parts list, and description and operation of the circuit are pain-stakingly written on the site. This is an excellent, excellent website! Check out Ken Stone's Modular Synth website.

Some pics to get your blood going...

So you finished your project and it's now in a 1u or 2u rack chassis. Very nice.

However, the problem is nobody else except you know what all those knobs and switches are for. You need a way to paint labels on thos knobs and switches so it looks like a commercial unit.

You can use a service like FrontPanelExpress and have them create the front panel for you. They'll take care of drilling the holes, and labeling them by engraving the text on the aluminum plate. The result is a very professional front panel. They even provide you with a CAD software so you can layout and create all kinds of holes and openings (including D-sub connections, XLR, etc.). Then you submit the resulting file and you bare aluminum  front panel to them and they'll ship you back a finished product.

This site belongs to an MIT student named Ladyada. The project is a very small MP3 player that can fit inside an Altoids mint can. She calls it the Minty MP3 player.

So for approx. $50, minimal total cost of $25 for parts, and $25 for a PCB, you can have your own MP3 player. This rates high on the geek factor. It's a pretty advanced project so if this is your first DIY, don't pick this as your first DIY project.

This guy from Korea can pack a lot of components into a teeny-tiny space. Great work. Some even have tubes while some are surface mounted components... that are hand soldered.

I use a Windows program called "Eagle" made by CadSoft Online. This is a great schematic to PCB design program to use. And best of all, it's FREE (some restrictions apply).  The learning curve is a little steep, but after a few hours of practice, it becomes intuitive and you begin to appreciate it's power and capability.



The Autorouter feature is great. Basically, the program will find the best possible path to connect your components together. Or, you can do it manually but the program still helps you by guiding you when connecting the points together.

Once you're done with your PCB design, you can send it off for manufacturing or prototyping.

UPDATE!!!!   Eagle software can now run on Mac OSX! Woohoo!!!  Caveat is, it's run under X11. But doesn't matter... because the files that I saved on the PC worked just fine when opened on the Mac OSX (X11) version.

Here's some screenshots.

The Eagle control panel running under OSX (X11)

The Board editor

This is a 32-knob, 16 switch MIDI Controller that can be used with any sequencer, like Sonar, DP, Logic or Ableton Live. By using the MIDI Learn function of your sequencer, and tweaking the knobs, you can train your sequencer to respond to the controls of this DIY MIDI Controller.

Want to have your own electronic drum set but can't afford a Roland set? This guy built his own drum kit using Radio Shack Piezo transducers, some jacks, and a few wires.  Of course, you'd still need the drum machine like a TD-7, but this will save you  hundreds by making your own drum pads.



And the finished drum set...



More information can be found here.

I haven't DIY'ed for a long time, so to kickstart this hobby again, I decided I'm going to build an 1176 Compressor.

The 1176 is one of the classic compressors in used by almost every recording studio out there. (The other classic compressor is the LA-2A). Bill Putnam designed the 1176, based on the 1108 preamp. Back in 1966, the Field Effect Transistor (FET) was just developed and he's experimenting with the properties of this new device. Basically, think of an FET as a "voltage controlled variable resistor."  The FET has three terminals. Drain, Source, and Gate. The resistance between the Drain and Source can  be varied/controlled by the Gate voltage. So what Mr. Putnam was doing with the FET is using it as a variable resistor to contorl the gain reduction in the circuit.

The output stage of the 1176 is a Class A line level amp, feeding a load of 600 ohms. It's got an output transformer which converts the output from unbalanced to balanced, and also do impedance matching. 

If you don't know or don't want to DIY, you can buy an 1176LN (for Low Noise) compressor for about $1800. Or, you can purchae "virtual" 1176 plugins from $130 to $225 price range. Click here for software plugin versions of the 1176.

A few years ago, the common wisdom was to "record as hot as you can." By HOT, I don't mean temperature wise. The wisdom at that time was to record your signal (from your guitar, keyboard, mic, etc.) so that the on-screen digital VU meters on your ProTools, Logic, DP, or Sonar is just hitting 0 dB, but not going over. Everybody knows that as soon as the red light turns on, you'll get clipping and digital clipping sounds nasty... like a fingernail scratching on a blackboard. ... The above argument sounds LOGICAL. There was even talk "you must use all of the bits as much as possible, so 0dB must be 1111111111111111 and that's good since we used up all the bits, nothing got wasted."

But something got forgotten along the way by the people who advised you to record close to 0dB in your DAW (Digital Audio Workstation... just a fancy name for a fast computer optimized for audio recording).

Read more ...

Just a work in progress.... using a breadboard. API schematics found on the Internet... just google API 312 schematic. You can see the printout of the schematic on the photo. I'm using a Melcor Discrete opamp instead of the original 2520 opamp (which you can't buy unless you have a broken 2520 to surrender to API). Although there are many substitute opamps you can use like the Jensen 990C, Forsell Technologies 992, John Hardy opamp, etc... or if you're really scraping, just use an NE5534 IC chip.