Award-winning microphone engineering from Michael Joly

MXL 4000 Mod with new MJE-K47 LDC Capsule

~~$399.00~~ $349.00

Click to enlarge

Introducing The New MJE-K47D Large Diaphragm Capsule Upgrade

There are just so many microphone options available today. After a lot of mic purchasing, research and development I've come up with some selection criteria to parse which mics are excellent candidates for modification. The MXL 4000 is ideal for a number of reasons; low initial cost - $199 for the multi-pattern 4000 and a highly acclaimed MXL 603 SDC, solid build quality, good circuit topology and yes, an impressive studio look.

Stock Mic Sound - The stock MXL 4000 was described as “precision grainy” and “digital sounding” on the GearSlutz.com forum. I would have to agree. This mic has an 8dB high frequency rise that tends to exacerbate audible flaws like less-than-ideal phase, amplitude and distortion performance. OktavaMod cleans up the acoustical and electronic environments of the mic and brings it to boutique sound.

Like most low cost microphones, the MXL 4000 uses a copy of the Neumann-designed K67 capsule. In the U 67 the rising response K67 capsule fed a complimentary de-emphasis circuit. This design created an acoustical pre-emphasis / electronic de-emphasis noise reduction system within the microphone and allowed control over tonal balance.

Problem is, almost all of the low cost microphones that use K67-style capsules do not include the de-emphasis circuit! Instead, the circuit following the capsule has a flat frequency response - this creates mics that are too bright and increases the likelihood of hard-clipping HF distortion.

Introducing the MJE-K47D capsule - a universal problem solver

The K67-style capsule is simply too bright to be used in a flat response circuit. So I've been hunting for a high quality K47-style capsule - its response curve is better suited to the circuit found in many low cost mics. The MJE-K47D (Michael Joly Editions K47-style, Double-sided) capsule is the result of my painstaking search to find a capsule producer who could manufacture a K47-style capsule to my quality control standards - and do so at an affordable price.

Each MJE-K47D capsule is individually tested in an anechoic chamber. Your modified mic comes with a signed Certificate of Authenticity from me - plus your individual capsules' actual anechoic chamber response. Which by the way, tracks an actual K47 capsule's response within +/- 1.5 dB across the audio spectrum.

Headbasket Upgrade - Converting the 4000’s headbasket to a single layer increases the open area percentage of the grille and reduces internal reflections that cause standing wave coloration. This modification delivers frequency response improvement (more top end sparkle) and time domain improvement (more precise transient response). This headbasket design pioneered in the AKG C 12 was subsequently used in the $5000 Manley Gold Reference mic and is now a standard feature of all OktavaMod large diaphragm mic modifications.

Capsule behind modified single-layer headbasket
This is Michael Joly writing, the founder of OktavaMod. Read on and find out if a modification to your MXL 4000 is right for you. Then either buy the mod or click "contact me" and send me your questions.

Wiring Upgrade – Multi-pattern mics are convenient but there is the potential of signal degradation due to stray capacitance loss between the capsule and FET input due to the extra wiring required to achieve pattern switching. The close proximity of signal wires to each other and the frame can cause signal degradation as the stray capacitance loads the capsule and bleeds off transient detail and sparkle.

Signal paths will be modified to avoid parallel wire runs and eliminate stray capacitive losses. This is a tedious process not used in high-volume manufacturing. It is like the construction techniques used in old-school radio transmitters where high impedance and high frequency circuits were the norm and required careful attention to wire type, insulation type, wire length and routing.

Input Coupling Capacitors Upgraded - The entire low level signal from the microphone's capsule passes through this one part - it has a critical impact on the sound of the mic! It is incredible that thousands of low cost mics have been, and are still being shipped with grainy, rough and edgy-sounding ceramic input coupling capacitors that cost less than 1 cent. On the plus side, MXL has upgraded the quality of the capacitors used throughout the circuit of the 4000. The input coupling caps are still not what I would use but they are a step up from the cheap ceramic caps used in their earlier mics. So the stock input caps in your mic will be replaced with my preferred part - a high quality, very stable, low distortion capacitor only available from one particular manufacturer. I really like the sweetness and lack of grain this change delivers.

FET Upgrade - Did you know that almost every low-cost microphone uses the same FET? It is true that the frequently used 2SK170 FET is a very low noise device, however it doesn't offer the best transient response possible. The FET in your mic will be upgraded (including re-biasing) with a faster device from one particular manufacture that has the best specs of any FET of its type. You'll hear more precise transients with greater sparkle, less "congestion" and better low level resolution.

Want to hear more sparkle; less edge, grit and hash while enjoying greater resolution in your MXL 4000? Just click "Add to Cart" to purchase the OktavaMod suite of modifications to your MXL 4000 for the introductory price of $349. Remember, this price includes the installation of my new MJE-K47D capsule. You'll get an immediate confirmation email of your order. By the close of the next business day you'll receive a personal email with your scheduled modification and return ship dates. Questions? Just click "Contact Me" - best, Michael

NEW! Check out the MJE-K47 Upgrade Suite - a universal problem solver for bright and sibilant mics

Award-winning Microphone Design by
Michael Joly