Hello, and welcome to our BLOG on how to build an audio console.
Why a Blog instead of You Tube ???
The first reason is that I do not now, nor ever intend to own a video camera. (That goes for cell phones as well)
The other reason is that when watching a You Tube Video, it is hard to "freeze" the frame so you can study it. (At least on my TV)
This site is going to be a Blog where you can blow up the pictures and the schematics for further study.
You can also copy/paste and store the information on your computer.
In other words, everything on this blog is available to you. (AS LONG AS YOU DON'T MAKE MONEY ON ANY OF THESE IDEAS)
On this Blog, you will find the basics on how to plan, construct and implement a 6 channel analog audio console based on the famous Radio Systems RS-12 Broadcast Audio Console.
Our 6 channel (2 input each) unit will also be expandable to 12 18 or even a 24 channel unit.
Why not go digital ?? Good question !! Digital Audio is a lot tougher to construct, and I don't want you to get frustrated.
In addition a digital console would be very expensive.
And for home use, an analog unit is just fine.
It is also designed to be easy to repair if needed.
And by the time we are done, you will be extremely familiar with the mixer, again to ease in repairs.
I have built a number of mixers in the past. Back in the late seventies, (yes, I am an old fart) I built a small 6 channel unit, to use in the newsroom at the radio station where I was employed.
(to my knowledge, no picture of that unit exists.)
Flash forward to the 2000's. I constructed a mixer based on a Broadcast Tools mixer.
This was a 12 channel (with 2 inputs on each channel) I constructed the mixer in a Plexiglass box. It had remote starts (turntable and timer clock reset) input select, as well as a PROGRAM and AUDITION bus.
A stereo LED meter was also used.
It worked, (passed audio) but was plagued by cross talk and some hum. Lesson learned.
Never pass consumer audio through switches and pots.
So I proceeded to start building a bigger unit.
I was able to score an input audio board from an RS 12 console, and used that as a base.
I was also able to obtain a TOP Frame of an RS-12 from my friends at Radio Systems. It contained the input control, volume pots, monitor switching, and V U Meters. As well as two clock/timers.
Then disaster struck. I had used part of my garage as a home studio, and one day I noticed that some of the channels were not working correctly.
Upon investigation, I found that a rodent had made his way into the unit and proceeded to destroy the input board as well as most of the wiring.
In a state of despair, I trashed the whole thing and bought a two complete RS console's on EBAY.
I ALSO KILLED THE DAMN RAT !!!
I was able to buy an RS-18 as well as an RS-24 for 500 bucks.
Now I had PARTS !!! As well as a working audio mixer.
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Time jump to today.
When I retired in 2017, my wife and I did a some considerable down sizing. I did bring my RS 18 with me to our new home and set it up in a converted walk in closet with my HAM Radio station.
The issue became the lack of space. I needed to get down to something smaller, yet functional to control my receivers. And I still had this yearning to build my own unit.
So I removed the large console to make way for a work space, and started this project.
Another reason for this project is my desire to design my own circuit boards. No etching for us. The cost of having them made professionally has gotten affordable, so that's the route we are taking.
In our quest for knowledge, I will share it all with you. The successes and the failures.
(Full Disclosure:) This mixer is NOT designed yet. That's what you and I are going to do, here on this blog.
We are NOT designing your mixer. We are designing mine. Your needs are going to differ than mine. But by the time we are done, you will have the knowledge to plan and construct your own mixer. One tailored to YOUR needs.
Although the mixer shares a lot of it's design with the RS series consoles, we plan to make a few major changes to eliminate a couple of inherent flaws in the way consoles were made back in the day.
So, come on along with this old geyser, and maybe, just maybe, you might learn something.
This is not a blog designed to teach electronics. There are plenty of resources you can turn to and discover how all this stuff works. I will recommend some as we proceed on this journey. My goal is to help you BUILD a mixer. I will assume you all have a basic, fundamental knowledge of electronics.
I also know that many of you have no desire to jump that deep into electronics. I will try to assist in that endeavor.
Before we begin, let's talk about shop safety. You will be dealing with HOT solder, as well as voltages. Make sure you know what you are doing !!!!!
This Blog is designed to help you, but we are NOT responsible for your actions.
So where to we begin ? Let's take a look at our mixer requirements.
(Your requirements WILL vary - - AND our ideas will more than likely change as we move along))
Power Supply
You need both a +/- 15 volt Supply, as well as a +/- 7.5 volt supply. You will also need a 5 volt supply to power the clock/timer. (You can run the clock from the 7.5 supply, but I like to keep them separate.)
Timer / Clock
I would like to have "select able" Clock/Timer. It needs to be used as a clock or a timer. I would use the Channel ON/OFF switch to re-set the timer. I use it to time my musical selections. I also want to use easy to find components. I am still trying to decide on a 12 or 24 hour version.
Input Select
Each input can select from one of two inputs, thus making this a 12 channel console in the space of a 6 channel unit. The input select card should also have provisions to re-set your timer.
Audio Control
A PCB with all the audio circuits. We will use V.C.A.'s (Voltage Controlled Amplifier) to control the levels. It will need to accept either Consumer or Professional audio . (10K vs 600 ohm-balanced)
Meters
A meter PCB to control either standard V U meters or LED metering. (Or both) For space reasons, I may make them "switchable".
MIX Buss
I want a Program channel, Audition Channel, and a MONO channel
Why MONO??? When you are working with BALANCED Audio, you can sometimes get a reversal of audio phase. This will only be evident while monitoring the MONO channel. A phase reversal will show as the level being cut in half.
Monitor
This will be a switch board to send signals to a monitoring board, This is where we will monitor PGM/AUD/MONO.
Cue and Headphone Amplifier
I am still undecided about a Cue Amplifier. For my use, I really don't need it. But you may, so I'll probably just build a proto type.
So how do we start ???
We've all seen that Life Insurance commercial that spouts, PRICE,PRICE,PRICE.
Here it is PLAN,PLAN,PLAN.
And when you are done planning, PLAN SOME MORE !!
I made a list that we can use to plan. write down ideas, and track our progress.
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MIXER PLANNING (NOT IN ORDER)
1) POWER SUPPLIES
+/- 15 V.D.C. XMFR 1
+/- 7.5 V.D.C. XMFR 1
+ 5.0 V.D.C. (CLOCK/TIMERS) XMFR 2 OR COMMERCIAL UNIT
SCHEMATICS
CIR BOARDS
CABINET
2) TIMER / CLOCK - SEPARATE UNITS FROM MIXER DUE TO SPACE LIMITS
12 HOUR MOD 60 MOD 60 MOD 12
24 HOUR MOD 60 MOD 60 MOD 23
TIMER UNIT
RE-SET PANEL
DISPLAY BOARD SCHEMATIC CIR BOARD
MAIN BOARD SCHEMATIC CIR BOARD
60 SEC/MIN MOD SCHEMATIC CIR BOARD
23 HOUR MOD SCHEMATIC CIR BOARD
12 HOUR MOD SCHEMATIC CIR BOARD
CABINET
PROTO TYPE
FINAL
3) HEADPHONE AMPLIFIER
DESIGN
SCHEMATIC
PROTO TYPE
CIRCUIT BOARD
4) CUE AMPLIFIER
CAN ALSO USE AS A TEST AMP WHILE BUILDING AUDIO BOARDS
DESIGN
SCHEMATICS
PROTO TYPE
CIRCUIT BOARDS
5) POWER AMPLIFIER (REPLACES TASCAM PA-30)
DESIGN
SCHEMATICS
PROTO TYPE
CIRCUIT BOARDS
6) OUTPUT BOARD
DESIGN
SCHEMATICS
PROTO TYPE
CIRCUIT BOARDS
7) MONITOR SELECT
DESIGN
AVOID OLD STYLE SWITCHES, USE DIGITAL
SCHEMATIC
PROTO TYPE
CIR. BOARD
8) PGM / AUD / MONO SELECT
DESIGN
AVOID OLD STYLE SWITCHES, USE DIGITAL
SCHEMATIC
PROTO TYPE
CIR. BOARD
9) INPUT SELECT
DESIGN
AVOID OLD STYLE SWITCHES, USE DIGITAL
SCHEMATIC
PROTO TYPE
CIR. BOARD
10) AUDIO INPUT BOARD
DESIGN
RS-12 VERSION
SCHEMATIC
PROTO TYPE
CIR. BOARD
11) MONITOR BOARD
DESIGN BASED ON MONITOR SELECT DESIGN
SCHEMATIC
PROTO TYPE
CIR. BOARD
12) EXTERNAL MONITOR BOARD
DESIGN
SCHEMATIC
PROTO TYPE
CIR BOARD
13) V U METER BOARD - SEPARATE UNIT ON SHELF
ONLY USED BECAUSE IT IS ALREADY BUILT
14) LED METERING - ON BOARD
USE RS-12 CIRCUIT REG LED'S OR BAR GRAPHS ????
SCHEMATICS
PROTO TYPE
CIRCUIT BOARD
15) D.A. AMPLIFIER
DESIGN
SCHEMATIC
PROTO TYPE
CIR BOARD
16) 4 PORT EX-PANDER BOARD
DESIGN
SCHEMATIC
PROTO TYPE
CIR BOARD
17) POWER SUPPLY DISTRIBUTION BOARD ??
MAY BE NEEDED WITH MULTIPLE BOARDS ??
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So that's what we have to work with.
17 Individual sections that once combined will result in a nice audio mixer that you can say 'I BUILT THIS!!!"
So, you ready ?????
As we go along, I will show you how to set up a small workplace, and different ways to construct a project such as this.
Let's get started.
Coming up next, we will talk a bit about setting up shop, then move on to a parts list and a discussion about power supply needs. You will need power supplies first, so you can test circuits as you go along.
Hope to see you then.
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(YOU CAN NOW MOVE ON TO CHAPTER 2 - SETTING UP SHOP)
God speed, Mother Nature.
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