Mic-Parts mods for MXL 990 condensor microphone

[justin3am]

I have a pair of MXL 990 condenser mics, they were the first condensor mics I ever bought. While I got a lot of use out of them at the time, they don't sound as good as other mics I have now. Still, I hung on to them for sentimental reasons.
I read about the Microphone Parts mod kits for these mics, a while ago and figured it might be a fun project.








It was a pretty easy project. The most difficult part was not losing any of the tiny screws. I chose the RK47 capsule. This combination is compared to a U87Ai on the mic-parts website but since I don't have that mic, I can't say.
With that said, the difference is immediately noticeable. Higher output, much smoother high end and huge improvement in mid range detail. Since I still have an un-modded one I will try to do some comparison recordings.

[CrystalWizard]

I’ve been curious about these kits for a while. I have two awesome mics already but i know quite a few people with low quality LDC mics ripe for the upgrade.

Btw the 47 is to mimic the U47 and i bet you wish you had one of them to compare

[justin3am]

Thanks for checking it out. I can definitely recommend the Mic-Parts stuff. The parts and PCBs are high quality and the kits are well documented. It was a very easy build. The circuit board just looks crowded because big parts are used. The pads are well spaced and large enough to solder easily (though might required a hotter iron).

While, their RK47 capsule is supposed to be like a Neumann K47 capsule, this particular setup doesn't sound like a U47. I worked at a studio where we had a vintage U47, and a Church mic which was very similar. I got pretty familiar with those two.

The 990 mod's circuitry is based on a transformer-less Schoeps mic. On the Mic-Parts website, they have some recordings comparing a modified 990 w/RK47 capsule, with a U87Ai (which uses a K67 capsule and is transformer coupled). The recordings do sound similar but I thought it was a weird comparison. Really, this is Frankenstein's mic, not exactly like anything.

My other LDCs (a pair of C414 XLIIs and a M-Audio Sputnik) have much brighter sound than this, so the darker character of this mic is welcome. I think it's gonna sound great on guitar cabinets and drums.

Based on this build, I think I may build their V251 kit, which is based on a Telefunken ElaM 251.

[xtp]

Cheers for this.

I have bookmarked the site. I have a Studio Projects C1 from about 2005 that I have never liked the sound of, might be an idea for a future project.

I have used those wima caps on some of the effects units i have designed, they have very short legs and have to be soldered on a day when my hands are steady.

[CrystalWizard]

Ah i see. I just gave a friend back his 990. I hadn't even used it as i have a (one) 414 and a nice Sennheiser but perhaps after an upgrade it will be more useful. Thanks for the detailed breakdown, caught my interest.

[Cheadle96]

Ive done a few Mic Parts Mods. All come out way better than the original. Ive DONE the AKG Preception 220 kit, MXL 990, and the Telefunken 251 and power supply. I would have to say the simple AKG was surprising and took about 30 minutes total. The Telefunken 251 was Outstanding. You have to do the power supply mod cause it really matters. It took 9 hours but was worth it. Did audio tests with all of them before and after.

[justin3am]

I'm all but certain to build a V251 kit some time this year. What PSU mod are you referring to? Is it mentioned in the build guide or is it mentioned somewhere else?

[bobdamiano]

I've done several MP kits and they are all very well designed and sound great. I've kept a bit of a blog about my mic builds including the MP ones.

[Uncle E]

Based on this build, I think I may build their V251 kit, which is based on a Telefunken ElaM 251.

I'm releasing an ELAM251 clone in a few weeks. Want to do a trade? There's a piece of Nektar hardware I've got my eyes on.

[justin3am]

Based on this build, I think I may build their V251 kit, which is based on a Telefunken ElaM 251.

I'm releasing an ELAM251 clone in a few weeks. Want to do a trade? There's a piece of Nektar hardware I've got my eyes on.

Thanks for the offer. I can help you with Nektar gear (send a PM) but it's more about the project, then the mic. I still want to build another MP kit but I'm up to my neck in projects at the moment.

[jupiterman7]

i did the TL3 Circuit Kit and Its one of my favorite mics!

[jupiterman7]

i also did the T84-55 Circuit Kit with a couple of old GT-55 mics again the results were amazing!