Modding a Røde NTK

How it all began

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I’ve had my Røde NTK for about 10 years. At first I loved it, at that time I was switching from a cheap Behringer condenser mic so it was a huge step up for me! After some time I started to study sound engineering and I got the chance to try out many different high quality microphones. While gaining experience and knowledge I slowly started to realize that there’s something harsh about my beloved NTK. I also noticed how full and smooth those expensive mics sounded, I could hear every detail so clear and there was a certain air around the recordings made with these mics.

After realizing I could not afford to buy a microphone like that I settled with my NTK. I EQ’d the hell out of every recording I made with it after that but I’ve never been 100% happy with the end result.

Years went by and I’ve been thinking about selling it a hundred times to buy another mic, but it never happened… At work we bought a Neumann TLM102 and I finally found a decent sounding mic that where within my price range! Still, my NTK stayed with me…

Then one day, I don’t know how I ended up there but I started reading on the internet about people who build their own recording equipment and modify their existing stuff to turn them into high quality gear.
I turned nuts, I read everything I could find, and I found some people who had modified their NTK’s, mainly people said that switching tube will make the mic shine… But I was so up in the air about this so I wanted to take it further and switch the capsule as well!

After careful investigation I decided to order a capsule from microphone-parts.com, their products were fairly priced and they seemed to have lots of satisfied customers. They have 5 different capsules all based upon classic capsules from Neumann and AKG. I listened to a lot of audio examples and read what other people had to say about them and I decided to go for their RK-12 which is based upon the capsule from the AKG C12 tube microphone.

“It is an excellent complement to a modern C12-style tube microphone mod, and a superior choice for any vocal or voiceover microphone.” /microphone-parts.com

I then followed Dale Simmons advice to go for a Telefunken tube, and I found one from the 60’s at Upscale Audio where the owner raved about this batch of tubes he had being one of the best he ever gotten hold of!

“Made in the 1960’s in Ulm Germany. This is the best made Telefunken 6922 / CCa / 7308 I have ever encountered. In fact… it’s the best testing tube I have ever had here regardless of brand.”

“These are shockingly good, so neutral and beautiful sounding you will name your next child after me.”
/Upscale Audio

Down to business

This was my first ever attempt at modifying any gear at all. It quickly became clear to me that I have to start with practicing my soldering skills, last time I soldered anything was back when I studied sound engineering.

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Switching the tube was a piece of cake, all I had to do was unscrew two screws then slide the stock tube out and slide the new-old 60’s Telefunken tube in and put back the screws.

The capsule was not really that hard to replace either once I mastered the fine art of soldering. Luckily the new capsule fit perfectly inside Rødes capsule holder and I cheated a little bit by borrowing the front cable from the stock capsule so I only had to solder one cable.

So finally, here’s the results! I wanted to actually hear the difference so I recorded some vocals and acoustic guitar first with my NTK unaltered, then with the Telefunken tube and stock capsule, then the new RK-12 capsule with the Telefunken tube and finally I put the stock tube back in just to hear what it would’ve sounded like if I only changed the capsule and to really get an idea what difference each part make. I also made a second recording with RK-12 + Telefunken after letting the tube burn in for another 2 days.

The recordings are made 30 cm away from the mic and goes in to a Motu 8pre, no EQ or compression. Unfortunately I forgot about the noisy computer we have in the studio I did the recordings in (we really have to do something about that), so the recordings are quite noisy but it’s nothing to do with the microphone.

This is it what it sounds like:

Guitar

Stock capsule + stock tube

Stock capsule + Telefunken tube

RK12 capsule + stock tube

RK12 capsule + Telefunken tube

RK12 capsule + Telefunken tube (Burned in)

Vocal 1 (Folsom Prison Blues)

Stock capsule + stock tube

Stock capsule + Telefunken tube

RK12 capsule + stock tube

RK12 capsule + Telefunken tube

RK12 capsule + Telefunken tube (Burned in)

Vocal 2 (Burnin’ And Lootin’)

Stock capsule + stock tube

Stock capsule + Telefunken tube

RK12 capsule + stock tube

RK12 capsule + Telefunken tube

RK12 capsule + Telefunken tube (Burned in)

Vocal + Guitar (Skinny Love)

RK12 + Telefunken tube (Burned in)

With gentle EQ, compression and reverb

Conclusion

I admit it’s not the best test in history, it was my first time doing this so I learned some lessons along the way. Still, the difference is obvious to me!

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My NTK is now much cleaner overall. It’s warmer, fuller and more balanced. Before I had to do surgical EQ adjustment to be somewhat satisfied with the sound of my voice and other recordnings, and I was still not 100% content with the result. Now all I have to do is some gentle EQ adjustments and it sounds better than ever!

I realized how important it is to let new tubes burn in properly, the sound became much cleaner and smoother. I’m also glad that I’ve decided to change both the tube and the capsule, once you’ve listened to the RK12 + Telefunken (Burned in) versions you don’t want to go back to any of the other versions. They both improve the sound of the microphone considerably!

Afterthoughts

 I’m totally in to this Do-it-Yourself business now, I’ve ordered two microphone kits from microphone-parts.com and a ribbon mic kit from diyribbonmic.com, it’s for my work where we gonna set up an electronic workshop where we can build, modify and fix our own gear. I’ve also ordered a PCB for a tube microphone preamp by Pete Millet, I realize it’s probably way out of my league at the moment… but if I have the PCB I’m gonna have to learn this stuff so I can build it one day…

Check out my latest single/video with vocals recorded on my precious NTK:

Now let me hear your thoughts on my NTK mod!