How to Perform the MCM DAC Mod October 26, 2010 07:10 13 Comments

Jim Williams of Audio Upgrades first tipped recording folks off to the MCM 50-7774, a "hidden treasure" D/A converter with a stellar DAC chip and a very low price tag. The design is an early version of the audiophile-endorsed Beresford TC-7510 that was licensed to OEM manufacturers. And, while it is marketed as a home hi-fi DAC, the 50-7774 has gained popularity among engineers as a professional mixing and mastering converter. The stock unit is impressive in itself (various Gearslutz members have said they prefer it to RME ADI8-Pro, Presonus Central Station, and MOTU 828 mkIII converters), but a couple of mods proposed by Williams and others can put it on par with really high-end DACs. The mods can be done in a couple of hours, and the whole project costs about $135 including the stock unit and premium replacement components.

I.J. Research now taking pre-orders for F76 October 21, 2010 04:49

I.J. Research (or "Igor" on the GroupDIY forum) is now taking orders for the F76, 1176-style compressor for the 500-series and 51x Alliance formats.  There are options for PCB-only or a partial kit with metal work.

 

Drip Announces Fairchild 670 PCB October 13, 2010 02:21 4 Comments

Two LA-3A Projects Announced October 12, 2010 03:43

October 4, 2010 shall henceforth be remembered as "The Day of the LA-3As" within the DIY community. On Monday both Peter Purpose, creator of such wonders as a full-featured 1084 for the 500-series, and Mike Pildis, of SB4000 fame, announced plans for LA-3A clone projects.

The UREI LA-3A is the solid-state sibling of the more famous LA-2A optical compressor. It might be called a hybrid of the LA-2A and 1176.

Check them out here:

• LAZ 500-series LA-3A
• SB-3A

The Newbie's Guide to DIY Jargon September 25, 2010 12:31 1 Comment

One of the defining traits of any group of hobbyists is a penchant for jargon: long words get truncated after the first syllable, phrases get compressed into acronyms and initialisms, and some special items even get affectionate nicknames.  This is all well and good for the initiated, but it can be confusing for the fledging enthusiast who has just started poking around on DIY message boards.  So, for the latter group, I have compiled a list of all of the abbreviations, acronyms, and pseudonyms that I remember scratching my head over.

AD/DA: Analog-to-Digital or Digital-to-Analog converter

Converts an analog signal into 1s and 0s for digital processing, and the other way around.  "One way" converters are referred to as ADCs (Analog-to-Digital converter) or DACs (Digital-to-Analog Converter).

BOM: Bill Of Materials

A list of all of the components needed for a particular project, often distributed in Microsoft Excel format.  A savvy builder can easily suss one out from a schematic, but having a pre-made BOM can make life a lot easier for the beginner.

Cap: Capacitor

DOA/opamp: Discrete Operational Amplifier

An operational amp built from discreet components (transistors, resistors, etc.).  DOA's are at the heart of many popular projects, including API and Twin Servopreamps.

DI: Direct Input or Injection or Interface

Converts an instrument input into a microphone-level signal.  Usually found as either a built-in option on a preamp, or as a small, stand-alone box.

DIY: Do It Yourself

EQ: Equalizer

FET: Field Effect Transistor

A type of transistor often encountered in audio circuits and the basis for a unique class of compressors.

IC: Integrated Circuit

An electronic circuit shrunk into a tiny piece of semiconductor material.  Used in modern audio equipment for opamps, VCAs, etc.

HPF/LPF: High Pass Filter / Low Pass Filter

LDC: Large Diaphragm Condenser microphone

LED: Light Emitting Diode

Omni: Omni-directional microphone

Opto: Optical

A type of compressor that uses a light source and a photo-conductive cell to determine gain reduction.  Opto compressors are often chosen for their "musical" non-linearities.  The most famous optical compressor is the Urei/Universal Audio LA-2A.

PCB: Printed Circuit Board

Pot: Potentiometer

A variable resistor with a sliding contact used to control such diverse variables as gain, attenuation, panning, balance, compression ratio, impedance, attack time, etc... Also colloquially known as a "knob."

Pre/Mic pre: Microphone preamplifier

Takes signal from a microphone and amplifies it--sometimes known to do cool, non-linear things (distortion, compression) to the signal in the process.

PSU: Power Supply Unit

RU: Rack Unit

Standardized unit for measuring the height of 19" rack mount cases.  1RU=1.75" or 44.45mm.

SDC: Small Diaphragm Condenser microphone

Schemo: Schematic

A circuit diagram using lines and symbols to represent connections and components.  Reading a schematic is a valuable skill, but not essential for getting started in DIY.

SMD: Surface Mount Device

A component that mounts directly to the surface of a circuit board.  Although SMDs are now predominant in consumer electronics, most DIY projects employ the older "thru-hole" mounting technology in which component leads are inserted into holes and soldered to pads on the PCB.

Trafo/Tranny/Iron: Transformer

TRS: Tip/Ring/Sleeve connectors

Also known as: phone, audio, 1/4" connectors.

Vari-µ: Variable-gain (µ) compressor. Pronounced "vari-mu."

A type of compressor than sets gain reduction according to changes in a tube's bias.  The Fairchild 660 is an especially famous variable-gain compressor.

VCA: Voltage Controlled Amplifier

An amplifier than varies it's gain according to a control voltage.  We often hear about VCAs in reference to VCA compressors, the most common and versatile type of hardware comp.

XLR: Cannon X Latch Rubber connector

 

Currently sourcing components... August 29, 2010 22:36 3 Comments

Welcome to DIYrecordingequipment.com! The goal of this site is to build a comprehensive and concise directory for all of the DIY recording equipment projects currently floating around the internet.You can also check out the ever-growing project directory to see what we've got so far. If you know of something you don't see, let us know!