The Rode NTK & K2 have classic build styles reminiscent of European classics of the golden era of sound. Rode microcrophones are a shining beacon of mass production here in Australia and have established a brand sound that many know. This modification is a great Alternative to buying an expensive vintage microphone as it offers sonics without the pricetag.
 
Enter the NTK OPR Ck12 MOD
It's important to point out that the capsule and it's housing or "head basket" is the ultimate dictator of the sound of any microphone,  imparting the all important sonic fingerprint or DNA if you will, other components matter too but but not nearly as much.
With that said going straight to the source and replacing the capsule with a quality unit is the best coarse of action. I use my hand made OP12 which is Modelled on the original brass Ck12 the capsule used in venerable C12 and 251 microphones which are now fetching $10,000- $30,000 USD. on the pro audio market.
The mod raises the NTK into a completely different league with a smooth yet open sound, airy highs, huge low end and glorious proximity effect that the classics are known for. To add icing to the cake the signal path is opened up sonically to allow the capture of every nuance and detail of the source.
 
With the O.P.R CK12 MOD the NTK just go a whole lot better!
Prices are excluding GST