Bounce to Disk

By Koji Mabuchi

Most home recording folks are familiar with and may have even experienced G.A.S. or, Gear Acquisition Syndrome—the compulsive and largely insatiable drive to buy that next microphone, preamp, guitar, or other piece of gear that will get you one step closer to the achieving the sonic Nirvana for your recordings as you imagine it in your mind’s ear. In the last year or so, I’ve become acutely afflicted with a less common variant of the disorder—G.M.S. or Gear Modification Syndrome. My thanks to TW for letting me ramble a little about what I’ve learned in the course of my affliction. A couple of caveats about this—first, if you record, proceed at your own risk as this may lead to spontaneous affliction with G.M.S., second, much of the information presented here should be filed under the category of “stuff I learned on the internet” and thus may not be completely accurate.

An excellent microphone tech who was doing some mod work for me once told me that a friend of his who also had technical skill bought one of the new Telefunken reissued ELAM 251’s that come in modern ($7,000) and vintage styles (a paltry $11,000). He opened up the mic and noticed that besides the capsule and transformer (admittedly the most expensive components in the mic), that there were about $70 in components in there. With the capsule, transformer, and microphone body and grill, could this amount to more than $1,000 in parts?

Mass manufacturing dictates that gear manufacturers make compromises such as using $0.05 capacitors and resistors, rather than $0.09 capacitors in your $100 preamp or microphone in order to be profitable. Economy of scale also makes it possible for the metalwork of the rack housing or the body and grill assemblies for your $100 preamp or microphone, respectively, to be manufactured at a cost that allows them to hit that $100 (or lower/higher) price point. Over the past ten years or so, many companies have shifted to buying OEM microphones from Chinese microphone manufacturing companies such as Alcatron, 797, and Feilo, which they then rebrand and sell domestically at market friendly price points.

This has created an interesting situation for both technically skilled DIY’ers as well as making it possible for small boutique manufacturers to utilize microphone (or outboard) components of Chinese manufacture and modify and upgrade them into considerably higher quality products.

Peluso Microphone Labs, a highly respected maker of microphones inspired by classics such as the Neumann U-47, the AKG C12, the ELAM 251, and several others, uses Chinese metal work for their capsules and bodies. John Peluso, the owner/operator of Peluso Microphone Labs, then gold sputters the microphone diaphragms in his own Virginia based facility. Charter Oak and Mojave Audio—both also respected manufacturer of higher end microphones, uses Chinese bodies, capsules and power supplies for their tube microphones. They build different circuits to match with the capsules and use better output transformers, but still use Chinese capsules, which are generally the most expensive electrical component in a microphone circuit as well as the most influential components in the sound of the microphone. How can they justify such practices—that the capsules in their $1000 microphones were manufactured in the same factory and by the same machines as the capsules in $50-$100 “Musicians Friend special” microphones sold by other companies? Through improved quality control—they inspect the capsules much more carefully and reject a much higher percentage of “bad” capsules than the manufacturers of those $50-100 who perform minimal quality control (you might get a good one, you might get a bad one; caveat emptor). In any case, their justification is ultimately the rave reviews that each company has received for their products.

As mentioned, the influx of these cheap microphones has provided a myriad of possibilities for skilled DIY’ers as well. There are numerous mods available for these cheap mics that can dramatically improve their performance (get your soldering irons heated up and your search engine of choice ready). Here are some notable ones:

One of the earliest and most popular is the “Dorsey Mod” (named for Scott Dorsey—mic guru and frequent Recording Magazine contributor). This basically is a way to take a cheap transformerless Chinese mic, and replace its entire circuit with one inspired by the classic Schoeps microphone circuit. The capsule, body and grill are all that are kept. This mod became so popular that it is widely believed that numerous microphone companies (such as the makers of those $50-100 Musicians Friend specials) actually altered their existing designs or created new models to incorporate the Schoeps/Dorsey circuit. Apparently you can contact Scott Dorsey and obtain the circuit board for this mod from him, and search the “Recording” magazine back issue index for the issue where he describes this mod and provides the necessary schematics and technical information to pull it off (apparently this is the highest selling Recording magazine issue in their history).

Dave Royer, the mind behind Royer Microphones—maker of high end ribbon mics and Mojave Audio—manufacturer of two highly respected tube microphones (the large diaphragm MA-200 and the small diaphragm MA-100) developed two mods (one for cheap Chinese large diaphragm mics, one for cheap Chinese small diaphragm mics) that work in a similar way to the Dorsey mod—replacing the entire circuit of cheap Chinese-manufactured microphones with new circuits (albeit in this case, tube circuits which in turn require tube power supplies to be built). These reviews each originally ran in TapeOp magazine and eventually became the basis for the Mojave Audio microphones. These are manufactured in China to stringent quality control standards with Chinese Capsules and bodies (reportedly sourced from ADK) and some components exported from the US to the Mojave factory. This is reportedly a fairly complicated mod (anything involving tubes has some inherent danger and building a power supply requires additional skills) and is not for the faint of heart. The TapeOp articles are still available on line. Royer used to sell kits for this mod, but doesn’t any longer, so if someone wants to do this, you’ll need to either wire it up on a breadboard or etch your own circuit board.

Scott Dorsey also developed a popular mod for the Oktava MK-219’s and 319’s which was published as an article in Recording Magazine as well. This entailed removing some of the unnecessary head basket elements from the microphone that negatively impacted sounds on the way to the microphone capsules, resulting in improved recorded sounds. Incidentally, Michael Joly of Oktavamod has taken the modification of these mics to new heights by developing levels of mods that replace key electronic components in the circuit (standard mod) or all of the components in the circuit except for the capsule and transformer (premium electronic mods). You might have seen Joel Hamilton’s rave review of his work in a recent TapeOp as well.

There’s an increasingly popular mod for the various Alcatron tube mics based roughly on the AKG C-12 circuit. These are sold under various brand names including Nady (TCM-1050, TCM-1150), Apex (460, 450), which both street for around $250-300, and were briefly sold in a huge faux pas by high end gear manufacturer Telefunken as the M-16 (MK I) for until an infamous Studio Forums review by Listening Sessions creator Dan Richards revealed that it was the same mic as the Apex 460 in a side by side comparison. These mods include upgrading key capacitors, upgrading the capsules to any number of choices (mostly Peluso manufactured capsules, NOS or used Neumann capsules, or higher quality Chinese capsules), upgrading the output transformers (to Cinemag, Jensens, or Tab-Funkenwerk (for the truly slutty) transformers), swapping out the cheap Chinese tubes for various NOS tubes—sometimes with different power ratings (e.g. substituting a 6072a for a stock 12ax7), and then in some cases, getting real picky and taking out cathode follower parts of the circuit or installing Zener diodes in the power supply to alter the way the tube circuit is powered for a more vintage sound. Various techs do these mods and the particulars can be found through a quick Google search.

There’s also a very popular mod for the Alcatron ribbon mics (also assembled in some form by 797 and possibly Feilo as well), that involves removing extra layers of protective material installed around the ribbon element (designed to protect the ribbon for overseas shipping, but universally agreed to muffle the sound) and replacing the crappy stock output transformers with a premium model from either Lundahl or Cinemag. Shinybox basically offers these commercially as the 46 series of ribbon mics, and Oktavamod has a modding service that does the same thing to user-supplied mics. Cascade has a line of ribbon mics that seem to basically amount to the same thing, though they maintain that their mics are manufactured in a different factory (possibly the 797 or Feilo factory (?)). This is supposedly a relatively simple, though somewhat delicate mod that DIY’ers have often reported doing successfully themselves.

Other prominent mic modders include: Jim Williams of Audio Upgrades, who is well known for his microphone, console, recorder, and other signal processing modifications, Klaus Heinz and Bill Bradley, respectively—each well-known for their high end (Neumann, etc.) modifications, Steve Sank—well known for modifying mid range to higher end ribbon mics (and now Behringer “toob” preamps and compressors). There are many more I haven’t mentioned (Need a referral? Let me know).