Echo North
Well-known member
Elements is built on the classic single op amp, transformer coupled microphone preamplifier circuit found in many classic console designs. A discrete op-amp in the standard 2520 provides variable gain, while the input and output transformers perform a wide range functions including circuit isolation, impedance matching, additional step up gain, and in some cases much of the tonal color.
This is a tried and true design that forms a simple but classic base for the Elements concept. Sonically, the possibilities are endless. The type of transformers, op amp, and capacitor selections have a drastic effect on the final sound. In addition to providing a base template for you to design your own mic pre, we’ve designed three unique mic pres that all have their own distinctive signature.
Offered in 500 series format, these pres will work in any standard 500 series rack and are a great first build for recordists familiar with basic soldering technique.
Features
Metalwork made in the USA:
A different color anodized aluminum faceplate according to which element kit you select. Clam shell side panel enclosure made from two pieces of 20 gauge steel, zinc electroplated, and coated in trivalent chromate, for maximum noise rejection at low and high frequencies.
Elements PCB:
The Elements PCB has been custom designed by Eisen Audio (Brooklyn, NYC) and draws from their popular DIY500 products (now discontinued), which were the first do-it-yourself kits in 500 series format.
Each kit includes:
Gold contact pushbutton switches and a gold plated DI jack that won’t tarnish over time. Standard potentiometers for gain and output from BI Tech’s P260 series. We auditioned several conductive plastic potentiometers, and found that these perform exceptionally well in terms of construction longevity and end-of-track noise. If you prefer stepped controls, we’ve worked with Eisen Audio and DIYRecordingEquipment.com to offer a simple and easy to install Grayhill switch and circuit that can be used in the gain and/or output position.
Transformers:
Our Gold, Copper, and Bronze Elements kits utilize high quality input and output transformers from Jensen, Cinemag, and Ed Anderson.
Op Amps:
We’ve commissioned two custom-designed discrete op amps in 2520 format: BA512 and Raindog, in addition to our Hairball JE-990 op amp.
DI:
The IC buffered DI is activated by relay when a instrument cable is inserted into the gold plated DI jack. The on-board DI buffer is prior to the input transformer, meaning the DI utilizes the entire mic pre signal chain. It’s a built-in complete DI box circuit.
Passives:
Elements complete kits feature only the best board-level passive components. Hairball Audio worked with Jens Jungkurth of Eisen Audio, leaning on his years of rebuild and design work, to select parts for dependability and performance. Jens’ years of working on classic recording boxes and consoles were invaluable for the capacitor selection and resistor trimming.
Welcome to the Elements series of Mic Pres!
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Schematic:
http://www.hairballaudio.com/elements/schematic.pdf
Build Guide:
http://www.hairballaudio.com/blog/d_assembly/elements-mic-pre-series/