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Author Topic: pin assignment JB mod nakamichi  (Read 975 times)

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Offline robeti

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pin assignment JB mod nakamichi
« on: April 27, 2018, 01:04:22 PM »
Hello,

I have a couple of JB modded Nak 300's and I'd like to have so cables made for them (mini xlr > mini jack with 4.7k mod in the plug.

Does anyone know the pin assignment of the JB mod naks?

Thanks in advance!
mics: nakamichi cm-50 | nakamichi cm-300 (JB mod/cp1/cp2/cp3) | primo em4052pmi4 | sp-cmc-4u/at-u853a 4.7k mod (h/c/sc)
power: ca-ubb | ca-9200
recorder: roland r-05
video: panasonic hdc-sd600 | panasonic hdc-700 | sony hx9v | sony hx50v

Offline old and in the way

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Re: pin assignment JB mod nakamichi
« Reply #1 on: April 27, 2018, 05:03:14 PM »
most three pin mic wiring goes pin 1ground 2positive 3 negative. to a trs i think ground shield, positive tip, negative center ring.

Offline kuba e

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Re: pin assignment JB mod nakamichi
« Reply #2 on: April 28, 2018, 06:27:40 AM »
most three pin mic wiring goes pin 1ground 2positive 3 negative. to a trs i think ground shield, positive tip, negative center ring.

This wiring is for condenser mics powered by P48. Naks are electret mics powered by 9 V battery. The connection should be pin1 ground, Pin2 audio and Pin3 power (voltage).  The FET connection in the original Nak is two-wire. I think you don't need 4.7k mod for modded Naks. Just connect ground (ground shield) to pin1, audio+voltage (tip for left or ring for right mic) to pin3 and leave pin2 free.

If you have problems with clipping, you can try to switch on -10 db pad inside Naks.
« Last Edit: April 28, 2018, 08:27:46 AM by kuba e »

Offline robeti

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Re: pin assignment JB mod nakamichi
« Reply #3 on: April 28, 2018, 10:57:19 AM »
Thanks!

I got cables made and I think they're good. However, I had very mild clipping at two shows.
I admit, I was almost glued to the stacks and ran my levels pretty hot so that's probably the problem. I'd rather not use the -10db pad. Just put my levels more conservatively next time and stay away from the stacks that close.

mics: nakamichi cm-50 | nakamichi cm-300 (JB mod/cp1/cp2/cp3) | primo em4052pmi4 | sp-cmc-4u/at-u853a 4.7k mod (h/c/sc)
power: ca-ubb | ca-9200
recorder: roland r-05
video: panasonic hdc-sd600 | panasonic hdc-700 | sony hx9v | sony hx50v

Offline kuba e

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Re: pin assignment JB mod nakamichi
« Reply #4 on: April 28, 2018, 04:33:25 PM »
The clipping may come from different places. It can arise in microphone, preamp or anywhere in the recording chain. In your case, If recorded signal is reaching 100% levels and it's peaks are cut off, then the clipping probably arise in recorder because the output of preamp is too hot. It is easy to correct it, set preamp levels lower.

If recorded signal is not reaching 100% levels and you have distortion, the distortion probably comes from microphone. The sound pressure level (SPL) is too high and the microphone capsule is giving too hot electric signal to the the electronics component inside mics body. When the electronic (FET) is overloaded, the distortion occurs. For this case the Naks have -10 db pad. It is between capsule and the electronic. The maximum SPL of Naks is 128 db. If you switch on -10db pad inside Naks then it is capable to record 138 db SPL. The 128 db SPL is sufficient with good reserve for our purpose. I think, JB mod is not lowering mic's maximal SPL, so you are safe here. I think too, you don't need 4.7 mod. I have read somewhere here it will not help to the Naks. Originally it is developed by Chris Church for mics AT853. This mod is not intended for all electret mics. You could unnecessarily lose some db in preamp input.
« Last Edit: April 28, 2018, 04:44:34 PM by kuba e »

Offline robeti

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Re: pin assignment JB mod nakamichi
« Reply #5 on: April 28, 2018, 05:12:54 PM »
Thanks a lot for all replies  :cheers:

I listened back to the tapes.
First tape is Band Of Skulls. cp1 caps. The band has a very distorted guitar sound at some points in combination with a small venue with not the best PA.
The tape came out briliant except for some super loud noisy guitar parts. Having said that: after listening back to another tape I made of them with AT853 mics I think it was the band/sound of PA not the mics.   

The other tape was Tom Chaplin. There's definitely clipping on that one.
Mostly not so loud music at all, but since I was very close to the stacks for this show, I could almost touch them, it might have been a spl problem.
I used the cp3 caps and I think it's not unlikely the spl was more than 128 db at some points from where I was standing. Thank God for earplugs  ;)

 

mics: nakamichi cm-50 | nakamichi cm-300 (JB mod/cp1/cp2/cp3) | primo em4052pmi4 | sp-cmc-4u/at-u853a 4.7k mod (h/c/sc)
power: ca-ubb | ca-9200
recorder: roland r-05
video: panasonic hdc-sd600 | panasonic hdc-700 | sony hx9v | sony hx50v

 

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