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Just an update to say that the transformer cans for the U87 body kit are in stock and will be included with all orders. We also have the screws for PCB attachment, included. And I think we've shipped them to all the early customers whose body kits had already shipped out.

Also, because there was some confusion I'll state more clearly (I hope!) that we ARE shipping body kits to Europe, and in fact have shipped many to destinations all over the world already.

(We ship capsules internationally too.)
 
We will soon be introducing two new mic mod kits. The circuits were designed by Jim Williams of Audio Upgrades. We're seeking "beta testers" because we want to be sure the instructions are good. Feedback from these initial builders will help us improve the product.

Both kits target the MXL 990. We have a Basic mod kit and an Advanced mod kit. The difference between the two is component count. The Basic kit is for less-experienced modders.

As you might know, the MXL 990 uses a version of the Schoeps transformerless circuit. It's a great circuit design, but implemented badly with low-quality parts. These cost-cutting measures make it an ideal target for modding -- a "diamond in the rough."

Read more about the mic here:
http://recordinghacks.com/microphones/MXL/990

Our Basic Mod kit is intended for first-time modders. It uses a handful of components to fix the worst of the problems with the circuit. The result is a mic with higher sensitivity, lower self-noise, wider frequency response, and a less congested sound. It's a solid upgrade, and when coupled with a capsule swap, it gives you a capable mic that you'll use in every session.

The Advanced kit goes a step farther, or maybe two steps. In addition to the changes in the Basic kit, it swaps out numerous additional components with high-grade and somewhat esoteric parts (fortunately JW has a stockpile!). The Advanced mod is based on the MCA SP1 mod that Jim did commercially for many years -- and, yes, we'll be offering SP1 versions of this mod soon too. It will open up the sound of the mic even more, lower the noise floor still farther, and improve transient response.

Both the 990 kits include detailed step-by-step instructions. Some of you would be fine with a bag of parts and a schematic, but we felt we could bring the magic of Jim's circuit mods to a much bigger audience if we instead showed exactly which parts go where. To be sure, you would still need to be comfortable with a soldering iron, as you will be removing and installing multiple components. But you need not reverse-engineer the existing circuit to succeed with these kits.

Update - the beta test program has been filled up; thanks to all for their interest!
 
Great to offer the Mod kits. The mod really makes a difference
I've got 2 SP1's modded by Jim Williams with the orginal capsules.
They sound great.
What replacement capsule is suggested or used in your kits?
Would my mic electronics require any adjustment or is the capsule a drop in replacement?
 
@kaguenpituak, we haven't compared them directly yet, but hope to soon.

@winetree, the JW circuit mod has a flat response; there's no filtering or EQ. K47 types like our RK-47 and RK7 are a great, natural fit. The RK-47 is a wonderful all-purpose capsule. The RK7 is darker, and has more proximity effect and more of a vintage vibe.

The RK-12 has a brighter profile, but the HF lift is broader than you get from a K67. It would probably not be as immediately useful as a K47-based mic, unless you love bright sounds, but it would be great for livening up dark instruments or for getting cymbal clarity on drum overheads. Female vocals can be great with this capsule too.

For our Advanced kit, we will offer a version for the K67/K87 capsule. It changes two cap values in order to attenuate the sharp HF boost of those capsules. But because your mic is already done, I wouldn't recommend hacking into what might have been a slightly different mod on the assumption that it would just work.

So, in short, I'd go for a K47 type or the RK-12. For kit customers, we'll offer a choice of any capsule.

We have audio samples of all these coming really soon, like hopefully within 48 hours, from a NYC voice artist who recorded narration samples into all 5 capsules at once (RK7, RK-47, RK-67, RK-12, RK-87). Following that we'll have lab tests showing frequency graphs. The voice samples are here, but not matched yet, alas.
 
The first session's worth of audio comparison files is finally available:
http://microphone-parts.com/audio-samples/

The source is male VO, doing both commercial and narration reads at distance of 6 inches. I supplied him with five MXL 990s that were stock, aside from the capsule and headbasket mods. He had one each of the K47 types (RK7, RK-47), the RK-12, and the K67 types (RK-67, RK-87).

In retrospect, I wish we'd modified these mics first, because I think the stock circuit has some low-frequency filtering due to undersized output caps. (This is one of the fixes in our Jim Williams-designed mod kit.) Nonetheless, the samples do illustrate the EQ differences inherent in these capsule designs.

The RK7 is the darkest of the bunch. A/B it with the RK-67 or RK-87, and the difference is obvious.

The RK-47 and RK-12 are tonally pretty similar, although the RK-47 has more going on in the mids, and the RK-12 has more air on top.

The RK-87 and RK-67 sound like they need corrective EQ. Which, as you know, they were designed to have. The MXL 990 version of the Schoeps circuit doesn't provide the necessary EQ, so the "eff" and "ess" sounds are slightly piercing and sound disconnected from the rest of the track.

There are more samples to come, with more audio sources. But I find it interesting that even on a relatively narrowband source like male voice, the EQ differences of these capsules are audible.
 
Just to add some personal experience; on a whim I decided to buy/build the 'advanced' MXL 990 mod. Instructions were clear and easy to follow (even for a moderate noob in this realm such as myself).

I did some tests with the stock unit, and some rough takes with the modded unit (not enough to make a comparison). Hope to get some better post mod tests done this weekend.
 
Just wanted to update folks that the RK-67 capsule (an excellent copy of the original K67, with 6-micron membranes) is back in stock. If you're building a D-U67, the RK-67 is a wonderful match for that circuit.

Our mod kits for the MXL 990, MXL V63M, MXL V57, and MCA SP-1 (designed by Jim Williams!) are in stock and shipping now too.
 
460mod.jpg


We've finally completed our mod kit for the Apex 460 tube mic. We're in the final stages of beta testing now, and expect to begin shipping kits (with discounted introductory pricing) on Feb 25.

The kit fixes the nonlinearities, noise and distortion in the stock Apex 460 circuit, and replaces both the tube and the capsule. We found that with a proper circuit, the stock transformer is linear from 30 Hz to nearly 40kHz (minus 0.5dB).

We've sourced some nice capacitors for the kit, such as a NOS TRW polystyrene input coupling cap plus the usual suspects from Wima, Elna (Silmic II), and Nichicon, and put together our best installation manual to date (incorporating feedback from dozens of customers of our FET mod kits).

If you've found your Apex 460 to be tinny, shrill, or "eshy," this mod kit will bring the mic out of the back of your locker and onto your favorite stand. The modded mic has a more musically useful frequency curve, lower noise, and much lower distortion.

You can choose from three capsule flavors: modern K47, vintage K47, or CK-12.

More info here: http://microphone-parts.com/mod-kits/


BTW, we have a really nice FET mod kit for the MXL 770 too now, designed by Jim Williams and based on his famous SP-1 mod but optimized to accommodate the pad and filter switches in the 770 and 990S.

 
sg-kit.jpg


We've cooked up an enhanced mod kit for the Apex 460. We had Reliable make up a special input coupling cap, and we sourced some crazily expensive pure silver solid-core wire from Kimber Kable, a gold-pin tube and imported 4% silver solder.

Details:
http://microphone-parts.com/mod-kits/apex-460-mods/#sg

 
We've adapted our advanced circuit mod kit for all the mics with an internal high-pass filter and transformerless output: CAD GXL2200 and GXL2400, Nady SCM-800 and some SCM-900, and the Apex 435.

These kits are on sale through the end of the month.

Also, for the GXL2200 and any other of these mics that comes with a large-diaphragm capsule from the factory, we offer a low-cost mod option that lets you retain the stock capsule, but apply corrective EQ within the circuit to take some of the edge out of the peaky high-frequency response. This kit is also on sale.

Details:
http://microphone-parts.com/mod-kits/cad-gxl2200-upgrades/

In addition to replacing nearly 100% of the audio circuit components, these new kits also deal with the chronic under-voltage situation found in these mics.

Pictured is the short-body version of this mic, e.g. GXL2400, Apex 435, SCM-800.

modded.jpg
 
We've just developed a circuit mod for the new surface-mount MXLs like the 910 and 550. The 910 is pictured below.

The mod corrects the current leak created by the lack of insulated standoffs on the PCB for the high-impedance capsule/JFET connection. It tunes up the bias voltage supply, and fixes that ugly input couping capacitor problem.

The kit also replaces the 2SK170 FET with a better FET that we pre-select to be properly biased by the stock MXL 240k/270k bias resistors. We went to this level because the stock FET exhibits hard asymmetric clipping as biased by the stock circuit. The top half of the image below shows the stock JFET failing to pass a clean sine wave. The bottom half shows our replacement FET at the same input signal level.
bias_results-191x300.jpg


The modification drops the self-noise, increases dynamic range, and reduces distortion. We bundle it with either of our two K47 capsules. The result is a pretty respectable mic for the price.

So, if you caved in during the recent "stupid deal of the day" on the MXL 910, here's an affordable way to make it sound much better. The kit price is just $20 beyond the cost of the capsule.

mxl-910-mod-300x300.jpg


For more info, or to order: http://microphone-parts.com/mod-kits/mxl-910-upgrades/

This kit definitely fits the MXL 910, and the current production (surface mount) MXL 550. Any other MXL mics who use identical surface-mount PCBs, including the MCA SP-1, would also be compatible.
 
New Schoeps-circuit PCB kits

v57a-300x300.jpg


We have two new PCB kits that fit most Chinese FET condensers.

Features:
  • multipattern operation (Cardioid/Omni)
  • 100% of circuit components are included
  • incorporates the Jim Williams circuit mods, plus additional improvements
  • includes pre-biased Siliconix J305 JFET
  • yields a high-sensitivity, very low-noise circuit
  • includes a bias voltage trimmer to fine-tune sensitivity across pairs of mics

The boards are 2-sided, PTH, made in the USA, RoHS/ENIG. We include mil-spec silver/teflon wire for board-to-board connections. Each PCB kit includes all components needed, plus PCB mounting screws and a detailed (30-page) full-color installation guide.

The installation guide includes options for creating a high-frequency shelf EQ to attenuate brightly-voiced capsules. This means you can use a K67 or CK12-style capsule with a bit of high-frequency rolloff in the circuit.

Compatibility
many-mxl.jpg

These boards were made to fit common donor mics, including but not limited to:
  • MCA SP-1
  • MXL 2006
  • MXL V63M
  • MXL 550
  • MXL V250
  • CAD GXL2200
  • MXL 910
  • MXL 2001
  • MXL V67G


Read more:
http://microphone-parts.com/mod-kits/mp-v57-pcb-kit/

They come in "round" too
IMG_9430_ccc-300x232.jpg

For the single-board edition, made for the MXL 990 and 990XL, see:
http://microphone-parts.com/mod-kits/990a-retrofit-pcb-kit/
 
Faster EU shipping!
shipping-banner2.png


We've opened a warehouse in the UK, allowing us to ship most EU orders from within the EU -- avoiding shipping delays and VAT!

Currently in stock in the UK warehouse:

No special ordering procedure is required. Wherever you live, just place your order via the microphone-parts.com website and we'll ship it from the nearest, most economical warehouse.

(The new PCB kits will be in stock in the UK by February 1, 2014.)
 

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