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Help needed with Original 90's RODE NT2
Old 4th October 2016
  #1
Help needed with Original 90's RODE NT2

I am wanting to experiment with my old RODE NT2 that I dug out of storage.
I have read there are all sorts of little hacks to tweak it into being a reasonably useful microphone.
The Capsule is kaput so that’s going to be the first replacement.

Whilst it still functions it’s a very harsh/sibilant sound & suffers from Plosive shutdowns of the circuit if one so much as breathes heavily 6-8 inches away from the diaphragm.
I’ve scoured the forums & read some very knowledgeable & helpful instructions to make these seemingly simple changes but need some help from someone with more electronics savvy to see if I have the right schematic as a reference point ?

My NT2 was one of the first batch from around 1992 & i just can’t seem to make sense of the actual physical parts layout Vs the schematic I found online [supposedly RODE NT2]
See attached links for pics/schematic: https://www.mediafire.com/folder/y1n1jjj60e7zf/RODE_NT2

Any help would be greatly appreciated.
Old 6th October 2016
  #2
Gear Nut
Quote:
Originally Posted by JohnnyBlack View Post
I am wanting to experiment with my old RODE NT2 that I dug out of storage.
I have read there are all sorts of little hacks to tweak it into being a reasonably useful microphone.
The Capsule is kaput so that’s going to be the first replacement.

Whilst it still functions it’s a very harsh/sibilant sound & suffers from Plosive shutdowns of the circuit if one so much as breathes heavily 6-8 inches away from the diaphragm.
I’ve scoured the forums & read some very knowledgeable & helpful instructions to make these seemingly simple changes but need some help from someone with more electronics savvy to see if I have the right schematic as a reference point ?

My NT2 was one of the first batch from around 1992 & i just can’t seem to make sense of the actual physical parts layout Vs the schematic I found online [supposedly RODE NT2]
See attached links for pics/schematic: https://www.mediafire.com/folder/y1n1jjj60e7zf/RODE_NT2

Any help would be greatly appreciated.
hi there,

I have an NT2 old version, sent it to Oktavamod, to do upgrade and replace capsule. It now sounds really excellent.

Funny coincidence my name is Jonathan Black.
Old 9th October 2016
  #3
That's my baby, warts and all. The polarization voltage is too high, it should be +60~62 volts. You can lower the zener diode value/voltage on the oscillator circuit board to do that. A series resistor of 1.5K ohms in line with the power/voltage feed from the audio pcb can help. A microphone-parts capsule can be swapped, watch out for the mounting geometry. A 414 capsule had a resonance created by the dome mount beneath it. Raising the capsule a few mm fixed that.

Replace the 22 ohm output resistors with 47.5 ohm CMF60 Dale resistors. Add a ferrite bead in series for extra rf protection. There are all sorts of other mods like polarizing the back plate to eliminate the 1000pf coupling cap etc.
Old 10th October 2016
  #4
Thanks for the replies Jonathon & Jim.

I have heard great things about the Oktavamod mods for the NT2 but it's probably not worth the cost of return shipping etc. [I'm in Australia]

It really is just a spare mic I had actually forgotten about so I don't think it warrants throwing a lot of dollars at.

I appreciate your input & knowledge of this [the original NT2], Jim Williams .
I see you were heavily involved in the R&D of what basically rescued Freedman Electronics & really helped to establish RODE & put the brand on the map.

Great to get some advice from someone who knows the Mic inside out or warts N all as you say.
I just need someone local who is more qualified than me to decipher your instructions & am quite keen to hopefully breathe some life back into the old thing.

I am an old Sydney boy so can still recall Freedman Electronics in Ashfield & their "Dynacord" outlet...Very much Pre- RODE era

Oow & Jonathon my name is John but surname isn't Black...It's been changed to protect the innocent !! Cool name though mate
Old 21st October 2016
  #5
Gear Head
 
SaraLs's Avatar
 

I brought my old NT-2 (purchased in 1999, it has a "B" prefix to it's serial number) out of retirement recently and replaced the capsule with a Mic-Parts RK-47 capsule. I made no other mods to the microphone, either physically or electrically. The RK-47 capsule really transformed it, it was no longer strident and had become quite smooth and just lovely. For about a week! Then it developed a low level noise, a rumbling and popping. Over a very short period of time, like 12 hours, the noise increased and the signal output decreased until the mic passed no signal what so ever. Before I rescued from the capsule from the carcass for another project, all it would do was produce a very faint white noise.

I'd love to repair the mic, and possibly do some of Jim's mods, but it's beyond my skill level to do the repair. Without available prints, it's WAY beyond my ability! Rode won't touch it ("it's too old, we can't get the parts"), and it would not be cost effective to spend money on someone else's services, anyway, not with used NT-2's are out there for around $200 US. So, it's become a lovely paperweight.

Some day I may decide to have it fixed, or attempt myself (anyway), but until then...it WAS a nice mic with the capsule mod!
Old 25th January 2017
  #6
Lives for gear
Quote:
Originally Posted by Jim Williams View Post
That's my baby, warts and all. The polarization voltage is too high, it should be +60~62 volts. You can lower the zener diode value/voltage on the oscillator circuit board to do that. A series resistor of 1.5K ohms in line with the power/voltage feed from the audio pcb can help. A microphone-parts capsule can be swapped, watch out for the mounting geometry. A 414 capsule had a resonance created by the dome mount beneath it. Raising the capsule a few mm fixed that.

Replace the 22 ohm output resistors with 47.5 ohm CMF60 Dale resistors. Add a ferrite bead in series for extra rf protection. There are all sorts of other mods like polarizing the back plate to eliminate the 1000pf coupling cap etc.
Thanks Jim, I have a pair of the original NT2's and was wondering if there's a way to create/extract a fig 8 pattern out of the mic, since it already has omni and cardioid ? I'd happily sacrifice one of those patterns to get fig 8 if it were a mod possibility ? I've attached the NT2 schematic (apparently this is it ?)
Attached Files
File Type: pdf RodeNT2 mic schematic.pdf (32.2 KB, 304 views)
Old 25th February 2017
  #7
Gear Maniac
 

Interesting that Rode can't get parts for your 1999 nt2.
I recently had noises from my 1998 nt2 and I phoned them in Sydney and they asked me to bring it in for a look. I took it to their factory, they phoned a couple of days later and I picked it up.
I was surprised that as well as fixing the sound problem, they also replaced the damaged head basket and also the body, which had a nasty dings in them.
Needless to say I was amazed when they didn't ask for any money!
Unbelievable service and company!
Got a customer for life.
Old 25th February 2017
  #8
Lives for gear
I'm in Australia so I might try an enquiry to them for the fig 8 mod...after all, nothing's actually faulty or broken in my pair of NT2's

I'm guessing that Rode mics are so well built and quality controlled from the factory these days that few get returned for repair or service (short of catastrophic or cosmetic damage during work in the field...most likely outdoor film shoots ?)

I've always found them a very helpful and responsive company when it comes to advice, purchases or seeking help.
Old 25th May 2020
  #9
Gear Head
 

Quote:
Originally Posted by Jim Williams View Post
That's my baby, warts and all. The polarization voltage is too high, it should be +60~62 volts. You can lower the zener diode value/voltage on the oscillator circuit board to do that. A series resistor of 1.5K ohms in line with the power/voltage feed from the audio pcb can help. A microphone-parts capsule can be swapped, watch out for the mounting geometry. A 414 capsule had a resonance created by the dome mount beneath it. Raising the capsule a few mm fixed that.

Replace the 22 ohm output resistors with 47.5 ohm CMF60 Dale resistors. Add a ferrite bead in series for extra rf protection. There are all sorts of other mods like polarizing the back plate to eliminate the 1000pf coupling cap etc.

So that first transfromer coupled design is yours too?

Does the transformer is a good one? Which ratio?
Does the circuit have a negative feedback?
Old 26th May 2020
  #10
The first version used a transformer. I re-did it without one, it was the first usage of the Schoeps style circuits used in a LDC. That was 1994.
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