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update 10/8/07
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2006 TAPE OP CONFERENCE: DIY EQ WORKSHOP TECH SUPPORT
OVERVIEW OF WORKSHOP: The project will be designing and building resonant EQ filters. This year will focus on theory as well as assembly, showing how to use inexpensive/free software to do filter design / test. Attendance to the class is $25, which covers the cost of your parts (neither Tape Op or Hamptone profit from this workshop). My goal is to teach some theory and to make something that would actually be of use in your studio when you are done. So I chose doing single filters, because a full 3-4 band eq would have had to be so simple to complete in the given time, that it would probably be no better than the EQs in a common commercial mixer. So instead you will build a simple filter, with selectable F/Q combining LRC (inductors, resistors, and capacitors) that has class A makeup gain. Although the design may may be limited in use, when it works it should work very nice (a great one trick pony). True LRC EQs sound so pretty, and if you just want to boost a little Hi on something, its nice not to go through a lot of opamps on your board when a simple resonant circuit will do the job. I built a selectable HI boost filter (12 selectable filters) specifically for my older RCA ribbon mics, and you can crank the HI end but it never gets abrasive. I've stolen from that circuit my two favorite filters as part of this design. THE DESIGN:
1. Active filter board with discrete class A makeup gain, regulated supply. 2. Controls: Boost/cut, filter select, filter adjust, overall gain. 3. All parts + 24vdc wallwart/jack are included. You will need to put it in a box, and provide knobs CIRCUIT SIMULATION PROGRAM The link below is to the Inusoft website where you can download a free version (limited to 20 components) of ICAPS4. I will show how to use this in the class to design and simulate simple EQ filters. I encourage people to download this, and bring it, or another program you might be familiar with as a comparison (maybe your is better!). WHAT TO BRING: Though Tape Op generously bought 100 soldering irons last year for the Tape Opto workshop, if you have one bring it. If you are new to soldering, it will be even harder with a bad iron (if not impossible). The Weller WP35 is a nice temp regulated soldering iron around $35 and would be worth the money if you plan on doing electronics in the future; and a good iron will last a long time, whereas the cheap ones tips degrade very quickly and make soldering quite difficult. Also small hand tools, cutters and pliers would be great, there is always a shortage of these things. SWEATSHOP OF DREAMS: If you did the compressor or preamp workshops in the past, you know that passing out the parts took up a bunch of time. To prevent that this year, I am planning on organizing people as they arrive into an assembly line putting the kits together. By working collectively in the "sweatshop of my dreams", we should be able to bag up the parts in a matter of minutes. I look forward to another great conference, and the 145' waterslide at the Hotel, see you there! Scott Hampton |
