EDC is a term used by Survivalists and Preppers, it means Every Day Carry. EDC can just be the thing you carry on you each day – sunglasses, wallet, keys, etc. However, it can also mean a prepared kit of useful tools and objects. With this in mind, I have developed a Sound Engineers EDC over the past couple of years, bear in mind that this is always a work in progress and gets updated regularly.
Over the years, quite a few people have approached me asking about how I got into audio electronics and, more specifically, building guitar effects pedals. So, here is my updated blog post on starting out, I’ve tried to add the information I found it hard to locate. It’s worth mentioning at this point that I build through-hole electronics, something that’s becoming less and less easy to do with the advent of surface mounted components which are getting smaller and smaller. One day I might get into building those types of circuits but for now, I’m happy to remain a “tinkerer” and “maker” over running a commercial operation. It’s a hobby not a business.
When you first start out, it’s very important to actually build circuits. You can support your experiments by reading up on the theory that accompanies the components and circuits you are using but nothing beats actually building the circuits … especially when you get them to work.
In order to quickly put circuits together you’ll need to have some prototyping equipment. I started out with the following gear…
- A multi-meter (£5-10)
- A solderless breadboard (£5-£25 depending on size)
- A battery clip (£1-1.50) & Battery (PP3 for most pedal circuits) (approx. £2)
- Some crocodile clips (£2-3)
- Some jump-cables/wiring kit (£15, or just buy some single core wire and cut to size yourself = cheaper)
- A small battery powered amp. (£15-£50)
SAFETY! It’s important, when first starting out only to power your circuits with a battery, including the amplifier. Thus, if you do make a mistake, like we all do occasionally, the worst you can do is pop a component or melt something! It’s a rite of passage in learning electronics.
Once you have acquired your prototyping gear, you will need a handful of components to experiment with. When I first started out, this is the information I found the hardest to locate, there’s absolutely masses of info out there but knowing where to star really helps, so here’s some pointers…
In order to build and prototype basic circuits you need a basic understanding of the following components: Resistors, Potentiometers, Capacitors, Diodes, Transistors & Operational Amplifiers
Remember audio is represented as A.C. (Alternating Current) in a circuit, so you need to know how these compenents work with both D.C. and A.C. There’s more about that in the BASIC CIRCUITS section below.
Armed with knowledge of these, you can build most buffers, boosters, distortion, fuzz, overdrive pedals plus a few more, such as tremolos and phasers.
Now you need to know which components will be most useful in prototyping, so here’s a guide to commonly used components (information which I would have found invaluable when I started out)…
Common Values used in Prototyping
Very common as a volume control: 100K-A (audio/Logarithmic taper). Other common values: 470 or 500 ohms, 1K, 5K, 25K, 47K or 50K, 100K, 250K, 1M
Resistors and Capacitors
The easiest way to tackle these is to buy a “kit” of each component type, such as:
Non-Polarized Capacitors (film are arguable better for audio)
http://www.rapidonline.com/Electronic-Components/Velleman-Electrolytic-Capacitor-Kit-120-Piece-13-0221 (approx. £8)
Some common values used in audio circuits…
- NPN Silicon Transistors
Very common: 2N3904, 2N2222A, 2N5088
Common: 2N3903, 2N2369A, 2N5089, 2N4401, MPSA18, MPSA13
- PNP Silicon Transistors
Very Common: 2N3906, 2N5087
- J-FET (Junction-Field Effect Transistors)
N-Channel’s: 2N5457, MPF102 and J201 (watch the pin out with the J201!)
- MOS-FET (Metal Oxide Semiconductor Field Effect Transistors)
(These are susceptible to static so be careful handling them.)
Silicon: 1N4148, 1N914 (Doesn’t matter which one, they’re both effectively the same)
L.E.D.s (Light Emitting Diodes)
Perhaps the most common of all is the 741 but a TL071 can be less noisy. You can also get these in multiple OpAmp packages, e.g. the TL072 contains two OpAmps and the TL074 contains 4 OpAmps. Some less common values include the JRC4885D (Ibanez Tube Screamer) and the LM308 (ProCo RAT) although both are tricky to source these days.
You need to build these circuits, to really appreciate how the circuit works. So, get building! As long as you run from battery, the very worst you can do is pop or melt some components (we’ve all done it, it’s part of the learning curve).
One of the most basic circuits you can build is a transistor based buffer, here’s a great page, with a excellent explanation of how they work. The common values of transistors and OpAmp mentioned above will work with all these buffers. Pay close attention to the part about Vr, as most transistor (and OpAmp) circuits need to be “biased”…
Once you have mastered that, the next step is to try a Fuzz Face circuit, which is, arguably the most famous fuzz circuit, based around two transistors. Pay attention to the polarity of the voltage on these.
Next would be to build an OpAmp circuit, such as a booster. Here’s one with the appropriate maths to work out the gain…
So get building!
The second episode in Systems Integration: XLR Patching.
The studio has four wall boxes, only two of which are in the same room. I wanted to create an effective way of getting these wall boxes to the sixteen mic pre’s in the console, so I opted for an XLR patchbay, because of slight danger of using a jack style patch chord with phantom power (the power briefly connects to the wrong side first). As the studio will be used by a variety of engineers and I also have some vintage ribbon mics, I wanted to make sure the patching was as logical as possible.
A great bulk of thee effort, involved with building this, was in bolting the XLR sockets into the patch panel, each socket requiring two tiny bolts and self-locking nuts. This process, in itself, took a good couple of hours to work through all 96 fixings.
Once that was complete, I had to de-solder all the tails that previously occupied the end of the cables before I could move onto soldering them to the new sockets.
Once this was complete I cable tested every single socket on the panel and wall boxes for continuity and polarity. Finding just two minor errors which were very easily corrected. It pays to be methodical with these things.
And, here it is, the finished panel, all labelled up. The bottom panel is the 16 mic pres in the Audient, and the top is the wall boxes. Of course, this also means I have effectively created a “wall box” in the Control Room too.
Should be incredibly easy to route signals from now on.
There comes a time in every studio owners life when s/he has to face the prospect of wiring four (often lots more) 96 point patchbays! The main decision is whether to do this yourself or get a decent wire-person to do it.
I opted for the former so, for most of this weekend, I have been wiring and soldering. As I mentioned in a previous post, going for DB25 d-sub patchbays made this easier and, opting for the Signex with solder pads for programming, the normals made it easier again.
Stage one was to assemble the parts. As I already had the layout of the bays planned, I decided to print the identification strips next. After half an hour or so changing column and row dimensions on Excel, I manged to print out some neat labels (I’m happy to share the Excel file if anyone needs it). Labeling the bays first made plugging in the DB25 to the correct connectors a lot easier.
The second stage was to half-normal three of the four Signex patchbays (see my Audio Geekery blog for more explanation). This just involved bridging some solder pads, three per channel and took less than an hour; I can see why these bays are so popular with industry installers.
The normals on one Q-Patch took longer, every circuit board had to be rotated 90 degrees.
Every cable and patchbay was then tested using a cable tester to make sure there were no dry joints or issues with the cables. I found a couple of issues with the cables, which were easily fixed with solder or manual manipulation of the jack/xlr connector.
Once the cabling and bays had been tested the lacing bars were installed…
…and, then, I spent the next day and a half cabling!
Here’s the final result. Four Bantam TT Signex Isopatch bays, integrating all the outboard and the console.
I still have the XLR bays to solder and install, I’m waiting on some parts before I can tackle…
…next week’s patchbay challenge!
As promised, here is the post for my fellow audio geeks.
This week I have been planning patchbay layouts for the studio.
We have 4 wall boxes feeding into the Control Room as follows…
Wall Box 1: 16 XLRf, 4 XLRm, 4 TRS jack. Located under the window in the Recording Room.
Wall Box 2: 8 XLRf, 4 TRS jack. This is found on the other side of the live room, near where the drum kit is usually set up.
Wall Box 3: 2 XLRf, 2 TRS jack. Located in the corridor between the Control Room and Recording Room.
Wall Box 4: 2 XLRf, 2 TRS jack. Upstairs in the lounge of the main house.
The Audient ASP4816 has 16 Mic Pres. We have 28 XLR sockets, so a patching system needed to be designed. Originally, I was going to bring the wall boxes and mic pres up on the bantam patchbays (more about those later). However, jacks (of any sort) don’t mix well with phantom power due to the way they connect. So, in order to protect the mic pres from inadvertent damage, I employed an XLR design to patch cabling back from microphone to mic pre…
I decided to build this out of panels, sockets and lacing bars. I order the parts this week so watch this space for pictures of soldering!
To feed the jacks on the wall boxes, I choose to employ a standard (A type) jackfield, semi-normalled…
Quick, technical aside: Half-normal means that whatever is on the top, of each channel, is automatically connected to the bottom until you plug a patch cable in the bottom, of said channel, which breaks this link, like this (from the Signex Isopatch manual)…
Both these bays are located in the rack unit, directly under the window in the Control Room, this has several advantages. Firstly, it provides the Control Room with its own “Wall Box”, so things can easily be patched into the mixer. Secondly, any additional equipment being used for a session can be placed on top of the rack unit and fed either to the console or into any other room with a wall box. Finally, by using XLR sockets for the mic pre patch, the phantom power issue is eliminated.
I’ve thought way too hard about this over the last few weeks, but nothing in comparison to how much thought I have given this…
This is the current layout for the main patch bay (to be located on the left hand side of the console). This went through so many iterations: Bantam vs. JPO B gauge jack versions, lots of layout revisions, considering room for growth, adding the tape machine once it’s up and running, adding more outboard, etc.
The layout, as it turns out, was fairly easy, it tends to suggest itself as you start designing and moving blocks around. By far the hardest decision in the process was solder tags vs. D-Sub DB25 connectors. Solder tags are more reliable long term, but harder to change if things need updating. After looking at more audio cable re-sellers sites than I care to mention, considering Neutrik, RE-AN (also Neutrik made), Switchcraft, Mosses & Mitchell. I decided to got for the Signex Bantam TT DB25 D-Sub bays as suggested by Pete Miles on a Facebook thread about this very topic.
I made the decision to go with these for several reasons:
1. They are Bantam, so can fit a lot more connections into a small space.
2. Signex are a good brand of patchbay.
3. Pro Tools and the Console Bus Output are on D-Subs, so D-Sub to D-Sub cable are all that’s required for that part of the system.
4. A lot less soldering to do, just some pads to bridge on the channels I want to half-normal or fully normal, looks simple enough…
5. This is the important one: Once I get the tape machine up and running it’ll be easy to implement it into the patchbay, even if I have to move things around. The thought of de-soldering and re-soldering the bays to accommodate “Analogue Warrior” (the Ampex MM1200) swayed me in the D-Sub direction.
Of course using D-Subs means thinking in banks of eight. I can change the connectors on the end, but stuff in each bank of 8 going to the console, can’t easily contain stuff going to the other patchbay (although there’s always some way of doing it) which made it an extra challenge.
So I have four of these bays on their way to me. Watch this space for photos of ridiculous amounts of analogue cabling!
Using the system should show up any flaws in my layout plan but, as it’s on D-Subs, it should be easy enough to reconfigure … that’s the plan anyway!