Rode NTK Mods
We think the Rode NTK microphone is pretty nice. But we've heard modified NTKs that sounded fantastic.
The modded NTKs that we loved so much had only two changes from stock:
- An RK-12 capsule
- A good 6922 tube
Finding a good 6922 is easier said than done. Most NOS tubes that we've tested are bad. We have not tested many 6922s, but we have tested many old 6072s. Even at $100-$200 per tube, more than 50% have one or more of these problems: low output, high distortion, high noise, microphonics. Worth noting: all of those 6072s came from a reputable dealer, and were described as "low noise, perfect for microphones."
High prices do not indicate quality. Look for tested/selected tubes. Do not buy old tubes without (a) a return window that gives you time to test the tube, and (b) relevant test equipment. If you can't test tubes for frequency response, noise, and distortion, you probably should not buy NOS tubes.
Also worth noting - of the two numbered mic changes above, the capsule is responsible for 90% of the upgrade. The sonic differences between an acceptable tube and a great tube are relatively subtle.
All that said, we find our 12-251 and V-251 kits to be superior to a modified NTK. We use nicer components than we've seen in any commercial production mic under $5000. Both of these products are available either as DIY kits or as finished mics. We offer a Platinum edition version of the V-251. We offer two levels of upgraded power supply, the VPS (kit or built) and the Platinum VPS (built only). It is not necessary, nor recommended to buy an NTK or any 3rd party mic for the express purpose of upgrading it.