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Rode NT1 Capsule Replacement
Old 29th December 2009
  #1
Gear Head
 
🎧 10 years
Rode NT1 Capsule Replacement

I just found a pair of old RODE NT1 microphones at the bottom of my mic locker. I can only remember buying one so it must have cloned itself in the 10-plus years it's been since dug all the way to the bottom of the box.

Rather then try to sell them for next to nothing on eBay I thought it would be interesting to swap the capsules or do something else to them to get them sounding usable. I really don't care for them stock. Has anyone had any luck modding these mics?

R
Old 29th December 2009
  #2
Gear Maniac
 
🎧 10 years
I'd be interested to hear any further discussion on this matter.
Old 29th December 2009 | Show parent
  #3
Gear Maniac
 
rodabod's Avatar
 
🎧 15 years
They have an odd capsule mount which may eb worth looking at first.

If it's a 797 capsule, then these can sound very good with some suitable filtering.
Old 29th December 2009 | Show parent
  #4
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illacov's Avatar
 
🎧 15 years
Talking

Excellent candidate for gutting, keeping the capsule and throwing in say a sub mini tube circuit or something like a 251 circuit with some adjustments to filtering like my man Rodabod mentioned.

Perhaps a strategically placed cap here and there eh??

I have an undying hatred for the NT1 and NT1a but the capsules might make for a cool sounding mic once you toss that SMD pcb and throw a good FET or tube circuit in there. I vote submini with a good transformer!

Peace
Illumination
Old 30th December 2009 | Show parent
  #5
Gear Head
 
🎧 10 years
Quote:
Originally Posted by illacov View Post
I have an undying hatred for the NT1 and NT1a but the capsules might make for a cool sounding mic once you toss that SMD pcb and throw a good FET or tube circuit in there. I vote submini with a good transformer!
I pulled the mic apart and expected to see a pcb with a buch of surface mount components but it actually looks pretty high quality to me. The build quality and the components used apear to be much better than my MXL 2001's (I also found a pair of those) which are from about the same period. Attached to this post are images from the inside of the RODE microphone.

Seeing the quality of the electronics in the microphone makes me think that it might be a better idea to chuck the capsule and replace it with a Peluso or something.

R
Attached Thumbnails
Rode NT1 Capsule Replacement-rode_nt1_cb_front.jpg   Rode NT1 Capsule Replacement-rode_nt1_cb_side.jpg   Rode NT1 Capsule Replacement-rode_nt1_capsule.jpg  
Old 30th December 2009 | Show parent
  #6
Gear Head
 
🎧 10 years
Quote:
Originally Posted by rodabod View Post
They have an odd capsule mount which may eb worth looking at first.

If it's a 797 capsule, then these can sound very good with some suitable filtering.
I'm guessing that the capsule is not a 797 or is built by them but is built to a different spec. I think (correct me if I'm wrong) that my MXL 2001s have standard 797 single-sided capsules (they look exactly like Peluso's CEK-89 single sided capsule). The capsule in the RODE microphone is different.

R
Old 30th December 2009 | Show parent
  #7
Lives for gear
That microphone was designed by Jim Williams, and I believe he has always thought the capsule was the weak link. You really can't get better passive components than what is already in there.
Old 30th December 2009 | Show parent
  #8
Gear Head
 
🎧 10 years
Quote:
Originally Posted by upinflames View Post
That microphone was designed by Jim Williams, and I believe he has always thought the capsule was the weak link. You really can't get better passive components than what is already in there.
The build quality and the components used really do look great. I'll shoot Jim Williams an email to see what he thinks I should do. It would be really great if I could just drop in new capsules and keep the microphones.

R
Old 30th December 2009 | Show parent
  #9
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illacov's Avatar
 
🎧 15 years
Talking

I used to have the NT1A I do believe that one is surface mount with opamps etc..The NT1 is much more promising.

Before you go dropping capsules in there it would be worth noting that the problem people usual mention with the NT1 and NT1A is that they are pretty harsh on the top end and sibilant.

I have no clue who designed it but I guess they figured using a filter cap to roll off some of that top end from that center terminated K67 variant was an inferior fix and left it out. Thus we have nails on a chalkboard as the purist result.

However time has shown otherwise.

Seeing as how that board can be soldered on without too many problems, I would look into putting a filter cap into the signal path of that microphone to tame down the highs a little.

I'd want to talk with Jim Jacobsen (my sensei) first about it, but I'd need a schemo too before I could say exactly where on your circuit board. I already have an idea though! Might save you a couple of bucks.

I already know that the capsule in that mic does well in a properly implemented tube circuit with appropriate filtering in place. As far as FET, if you like the way the circuit is or believe it to be then by all means augment it. Buying a different capsule isn't going to change the circuit. If its wide open then its not set up appropriately for a K67 at all. There are a gagillion threads on the internet about the proper way to use a K67 capsule.

Peace
Illumination
Old 30th December 2009
  #10
Gear Head
 
🎧 10 years
Capsule Info

For what it's worth the capsule in the NT1 seems to be the exact same one that's in the Soundelux U195. Here's a photo from recording hacks:

Old 30th December 2009 | Show parent
  #11
Gear Maniac
 
rodabod's Avatar
 
🎧 15 years
Looks to be a 797 capsule to me. You can make a very nice sounding mic with this capsule in my opinion if you use a circuit with adequate HF filtering.

You could possibly either mod the current circuit if you have a schematic, or fit a new circuit to suit. I personally find that transformer outputs can help to soften the top-end further.
Old 30th December 2009 | Show parent
  #12
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illacov's Avatar
 
🎧 15 years
Talking

Quote:
Originally Posted by rodabod View Post
Looks to be a 797 capsule to me. You can make a very nice sounding mic with this capsule in my opinion if you use a circuit with adequate HF filtering.

You could possibly either mod the current circuit if you have a schematic, or fit a new circuit to suit. I personally find that transformer outputs can help to soften the top-end further.
thumbsup

I concur, it doesn't matter who designed the darn thing, there's obviously room for improvement!

Roddy,

help me out here.

Cap across FET to ???

Just brainstorming

Peace
Illumination
Old 31st December 2009 | Show parent
  #13
Gear Head
 
🎧 10 years
Just for grins I put a capsule from one of my MXL 2001's in one of the RODE NT1s. I recorded two takes of me playing a guitar (i'm not a guitar player so forgive the performance) with both the stock RODE mic and the one with the MXL capsule. The mics were in the same RODE mount (the one that screws to the bottom of the mic) pointed at the same spot on a Taylor DN3 guitar (between the body and the 12th fret) at the same distance. The recordings were made using the same channel of a Yamaha N12. I didn't touch the channel's gain between takes and I didn't level match or do any processing on the files.

It's not scientific but it is interesting.
Attached Files

Rode_MXL_Capsule.wav (5.55 MB, 18415 views)

Rode_Stock_Capsule.wav (5.55 MB, 18455 views)

Old 31st December 2009 | Show parent
  #14
Gear Maniac
 
rodabod's Avatar
 
🎧 15 years
Quote:
Originally Posted by illacov View Post
Cap across FET to ???
I don't know the circuit at all, but it's quite possible that some HF feedback could be added around one of the amp stages to reduce treble response like I think you were suggesting.
Old 31st December 2009 | Show parent
  #15
Gear Guru
Lucky boy. You have an original NT-1A.

I designed it with super low noise Hitachi transistors and a Siliconix rf jfet. As you can see it has German Roederstein metal film resistors and Wima polypropylene film caps. As it is there is little to do to improve it. It was built "modified". Peter Freedman did try to use lesser quality parts after the design but elected to use the quality parts I designated as they also heard the improved sonics from those parts. The NT-2 was repriced from $699 to $749 to include the quality parts.
Since then, competition has been fierce. Peter elected to lower the production costs of the Rode line so that's when the good stuff was chucked for all low cost surface mount parts. Those are the Rode mics you see today.

There are no frequency feedback nets in that design. There are a pair of 470 pf caps at the base of each Hitachi output transistor to ground that you can increase the value of to lower hf bandwidth. Try 1500 or 2200 pf.

The capsule is an odd duck with it's metal disc. It has no coating on the rear so it's cardiode only and has very low self noise.

The same design and circuit was also used in the original NT-2 mics but only that capsule is different. It also had a switch to add the rear diaphram for omni patterns.

Jim Williams
Audio Upgrades
Old 31st December 2009 | Show parent
  #16
Gear Head
 
🎧 10 years
Quote:
Originally Posted by Jim Williams View Post
Lucky boy. You have an original NT-1A.
I think I might have two of them. On closer inspection it looks as though the two NT-1s I have are different. The one I put the MXL capsule in is shorter and has the RODE NT1 name screened on the front. The other one is taller, has nothing silk screened on the front but it has the RODE NT-1 model printed on a black band on the base. The serial number on that one is hand written with a sharpie next to the model name.

The electronics in the two seem to be the same. There're small differences with the screening on the PCBs and the resistors seem flipped between the two but other then that they're the same. I've attached photos.

Jim, do you think the sound of these mics could be improved with a different head-basket and/or capsule? The quality of the electronics used is first rate. The sound has been described as "wonky" and I think think that's a good way to put it. The off-axis response of these mics is strange and seems very unforgiving compared to other mics I own. I wonder if it could be an accoustic issue with the "chain link" headbasket and the asymmetrical padding inside? I think i might shove one in empty MXL mic housing I've got and see what that sounds like.

R
Attached Thumbnails
Rode NT1 Capsule Replacement-rode_side_by_side.jpg   Rode NT1 Capsule Replacement-rode_side_by_side_naked.jpg   Rode NT1 Capsule Replacement-rode_nt1_mxl_capsule.jpg  
Old 31st December 2009 | Show parent
  #17
Gear Head
 
🎧 10 years
Just for the heck of it I put the RODE NT1 with the MXL capsule in a MXL 2001 head basket. I encased the body in several layers of tinfoil as the MXL housing was too narrow. Here's a recording using the same guitar, channel, pick, spacing etc as the earlier takes.

R
Attached Thumbnails
Rode NT1 Capsule Replacement-rode_mxl_hb_tinfoil.jpg  
Attached Files

Rode_MXL_HB_and_Cap.wav (5.55 MB, 17637 views)

Old 1st January 2010 | Show parent
  #18
Gear Head
 
🎧 10 years
I just pulled two layers of the internal mesh from the MXL headbasket and the sound opened up a lot. The level of the recording appears to have been reduced, however it sounds more balanced now to my ears. A low-mid bump that was there before has vanashed.

I wonder if the stock RODE headbaskets could benifit from a similar treatment? They have very strange asymmetrical mesh layers that could be causing a lot of the signature, almost "phasey" sound one gets from them. The pattern's opened up a bit as well. Off axis sound is more natural.

Later I'll put the stock capsule back in the RODE and give it another go with the MXL head basket.

R
Attached Files

Rode_MXL_HB_1layer_and_Cap.wav (5.55 MB, 17454 views)

Old 9th January 2010 | Show parent
  #19
Lives for gear
 
changeng's Avatar
 
3 Reviews written
🎧 15 years
help!!!

i got curious and opened my NT-1 and what the ?

I had dinged the headbasket of it a few years ago and RODE replaced it for free (thanks guys!) and it looks like there's a long metal rod that I suppose connected to the rubber holder, keeping the capsule in place - is this normal? what a weird design! Now it's sideways and can't find it's way home... methinks it's about to become a future frankenstein, since I don't think i'll have the patience to even try to poke it back into place (and of course there's no screw to remove the headbasket.

What is a great cheap capsule for this mic to take advantage of the nice board? A ridiculously cheap mic with a surprisingly good capsule that would be a good match?

Is the MXL 2001 the best capsule for this? I have an old Behringer B-1 (the board says Beijing 797 on it - would the capsule of this thing be a decent replacement?

Thanks in advance!

Last edited by changeng; 9th January 2010 at 05:30 AM.. Reason: clarity
Old 9th January 2010 | Show parent
  #20
Gear Maniac
 
rodabod's Avatar
 
🎧 15 years
Quote:
Originally Posted by changeng View Post
Is the MXL 2001 the best capsule for this? I have an old Behringer B-1 (the board says Beijing 797 on it - would the capsule of this thing be a decent replacement?
Use the Behringer's capsule if need be, The 797s are better than the typical MXL caps which tend to be bog-standard 32mm shaghai models.
Old 10th January 2010 | Show parent
  #21
Lives for gear
 
Michael_Joly's Avatar
 
🎧 15 years
The biggest issue with this mic is the headbasket - The outside grille is one piece of wire mesh stamped into shape - no wonder the open-area is so crowded at the bottom and at the sides. Talk about putting the capsule in a box - I'll bet the percentage of open area in that headbasket is less than 18%.

Look at my MJE-K47H capsule head below to see an approach that is far more acoustically transparent, open-sounding, essentially free from internal reflection coloration and has better pattern control.
Old 10th January 2010 | Show parent
  #22
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changeng's Avatar
 
3 Reviews written
🎧 15 years
I did put the Behringer capsule in the NT-1 tonight and tore out the inner mesh of that crowded headbasket - it's actually pretty decent sounding now- it's crispy (chinese capsule) and lacks a tiny bit of bottom end - almost has a dynamic quality to it. A/B'd it with my Genesis tube mic and it did surprisingly well. A good capsule on Jim Williams' original NT-1 design should turn out a nice product - Mike - have you torn into yours yet? Can't wait to see what you end up with. In the case of mating a bland mic (NT-1) with a boinky mic (B-1), it actually works! NOTE: mine is the original NT-1, not the NT-1a.
Old 10th January 2010 | Show parent
  #23
Gear Maniac
 
rodabod's Avatar
 
🎧 15 years
I'd listen to Jim Williams.
Old 12th January 2010 | Show parent
  #24
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changeng's Avatar
 
3 Reviews written
🎧 15 years
A couple days later and the mic is still sounding good - i won't do the roll-off thing that Jim Williams mentioned, since it will still include the spike. I'd love to find a way of inserting the proper filters into the circuit, or mayb find a more '47' style capsule, as Michael has mentioned on occasion. Jim Williams designed a real nice board for the NT-1 and the 797 capsule comes soooo close to being a great match for it. I wonder how many people have this sitting in a closet when all it needed was a decent capsule.
Old 12th January 2010 | Show parent
  #25
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illacov's Avatar
 
🎧 15 years
Talking

Quote:
Originally Posted by changeng View Post
A couple days later and the mic is still sounding good - i won't do the roll-off thing that Jim Williams mentioned, since it will still include the spike. I'd love to find a way of inserting the proper filters into the circuit, or mayb find a more '47' style capsule, as Michael has mentioned on occasion. Jim Williams designed a real nice board for the NT-1 and the 797 capsule comes soooo close to being a great match for it. I wonder how many people have this sitting in a closet when all it needed was a decent capsule.
What could it hurt to try though??

That "spike," you're talking about didn't stop Georg Neumann from using a lopass in his mics.

That foil on the mic rudolpho put together reminds me of jiffy pop. I love popcorn!

Peace
Illumination
Old 12th January 2010 | Show parent
  #26
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Haz-Mat-Strat's Avatar
 
🎧 10 years
Quote:
Originally Posted by changeng View Post
A couple days later and the mic is still sounding good - i won't do the roll-off thing that Jim Williams mentioned, since it will still include the spike. I'd love to find a way of inserting the proper filters into the circuit, or mayb find a more '47' style capsule, as Michael has mentioned on occasion. Jim Williams designed a real nice board for the NT-1 and the 797 capsule comes soooo close to being a great match for it. I wonder how many people have this sitting in a closet when all it needed was a decent capsule.

You are right, the design of this mic uses high quality components. The head amp is very clean and flat (by design). I think Jim answered your question.

Quote: I'd love to find a way of inserting the proper filters into the circuit.

Jim Williams: There are a pair of 470 pf caps at the base of each Hitachi output transistor to ground that you can increase the value of to lower hf bandwidth. Try 1500 or 2200 pf.

You are trying to tame the high end of this mic. You are not trying to make this a flat microphone. This is what the designer has said would work. You are fine tuning this mic for your own taste. The "spike" you refer to has been tuned in the past to produce some of the best "industry standard" microphones.

I have done extensive testing on tuning microphones and found that the frequency response can be tuned easily without adding the problems surrounding excessive EQ. If you try to make the response of a K67 flat, EQ /excessive filtering, you will add more phase issues into the mix and loose the good qualities about this capsule.

The mod that Jim told you about, will take off the "edge" that you do not find usefull. Buy some good caps (same caps that are in the mic) start at 1000pf and go to 2200PF record each step and make an evaulation when you are finished. Not only is this an inexpensive "fix" it gives you the power to "tune" your microphone.

Rodabod is right:
I'd listen to Jim Williams.

Jim Jacobsen
JJ Audio
Custom Microphones and Mods
Old 12th January 2010 | Show parent
  #27
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Michael_Joly's Avatar
 
🎧 15 years
Then after you've done that, replace the headbasket with one that has greater open area. Internal reflections in the stock headbasket only exacerbate the issue of a K67-type capsule driving a flat response circuit. Then you'll begin to hear what a K67-type capsule really sounds like.

I mean, think about it. Have you ever seen a Neumann mic equipped with a K67 capsule use a headbasket like the one in the NT1 and NT1a? - A headbasket that is vitrually closed at the sides and bottom 1/3 of the front and rear grilles?
Old 13th January 2010 | Show parent
  #28
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Haz-Mat-Strat's Avatar
 
🎧 10 years
Hi Michael

The phase/ reflection issues in the headbasket are the major concern with this mic. You have a good circuit coupled with a bad grill design. That should have been addressed by Rode in the design phase of this mic. I think they were looking for "unique style" over function, when they designed the grill. The capsule mount leaves a lot to be desired also. If serious improvements are to be made to this mic, the head basket needs to be replaced or modified.

Do you know of a headbasket that will fit the Rode?
Have you taken out the mesh layers on one of these mics before? (I have not taken one apart)
What kind of metal is the haedbasket ring?

If the bottom ring is brass, a headbasket can be fabricated using the NT1 bottom ring and adding a brass strut and grill similar to the MXL headbasket pictured in Rudolpho's post. That would make the mic respond better to any capsule that is in the NT1.

Best,
Jim Jacobsen
JJ Audio
Custom Microphones and Mods

PS: Michael, Thanks for the contact
Old 16th January 2010 | Show parent
  #29
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Michael_Joly's Avatar
 
🎧 15 years
I've completed an intense period of R&D and now have a new modification for the RODE NT1a - new, more open-area "67 / 87" style headbasket and MJE-K47 capsule. Sounds righteous with that low noise (5 dBa) circuit in this mic. No more sizzle, just classic midrange punch.
Attached Thumbnails
Rode NT1 Capsule Replacement-michael_joly_nt1a_mod2.jpg  
Old 17th January 2010 | Show parent
  #30
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mljung's Avatar
 
1 Review written
🎧 10 years
Quote:
Originally Posted by Michael_Joly View Post
I've completed an intense period of R&D and now have a new modification for the RODE NT1a - new, more open-area "67 / 87" style headbasket and MJE-K47 capsule. Sounds righteous with that low noise (5 dBa) circuit in this mic. No more sizzle, just classic midrange punch.
Wow Michael

I happen to have two NT-2 [originals] from the time when RΓΈde was the new big thing in the microphone businessstike. I always had a feeling that something was good about them, but the capsule is definitely bright and edgy, as many have reported [and I haven't used them for a long, long time for that same reason].

Anyhow, the NT-2 has a more open headbasket than NT-1, and I thought maybe I should just try a replacement K-47 capsule. Do you think this would work and could this be fairly easily done. [There's no doubt that I would prefer your work on it Michael, but sending to US from Europe and back again, taxes and custom fees, makes this operation pretty expensive].

Best,
Mads
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