line to mic level using Neutrik NTE10/3 transformer

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Natural

Member
Joined
Oct 21, 2019
Messages
12
Hi there,

i would like to convert Line level audio to mic level using a transformer to protect my camera. witch is battery powered in contrast to the audio gear.

i found some schematics and would like to know how it's done correctly using the Neutric NTE10/3, witch i have bought in an impulse.
toonregelins.png

https://www.soundcardpacket.org/7cablerx.aspx
1rxtransformer.GIF


it's the first time i'm using a transformer in the audio biznis, don't know much about it.
did someone tried this?

kind regards and thanks in advance.

 
Natural said:
i found some schematics and would like to know how it's done correctly using the Neutric NTE10/3, witch i have bought in an impulse.
You could have done worse... :)

1rxtransformer.GIF

did someone tried this?
Yes.

That should work; the only risk is, if the line level is excessive, saturating the transformer. You may need an attenuator, such as this
https://www.thomann.de/fr/jts_ma_123.htm?glp=1&gclid=CjwKCAjw5Ij2BRBdEiwA0Frc9ebx97n9gPRNZ_m1sg2HgKS11ZTzAiUVHvcitLsMfan9EOBkcjmiWxoC8TkQAvD_BwE
 
Hey thnx for your reply.

how about this?
1txtransformer.gif

taken from:
https://www.soundcardpacket.org/7cabletx.aspx

well the line level input is no problem, i can use opamps and reduce the gain.
as my gear is 10 v.p.p., but i can't have opamp or any parts powered by my gear on the secondary side.
i wanna protect the camera witch is battery powered.

i bought that Neutrik transformer in an impulse and i wanted to know if that type/model does the job.
https://www.neutrik.com/en/product/nte10-3
H212380Z.jpg

it's center tapped, being 10K on 1 side and 50K on the other.
witch should i use?

i don't know anything or little about transformers in the audio world.

kind regards
 
Why don't you simply buy a passive DI-Box, one like these:
https://www.thomann.de/de/millenium_die_dibox_passiv.htm?ref=intl&shp=eyJjb3VudHJ5IjoiZGUiLCJjdXJyZW5jeSI6IjIiLCJsYW5ndWFnZSI6ImRlIn0%3D

 
well, i'm building a DIY modular synthesizer.

i have reduced the gain from 10 v.p.p. to line level using 3.5 mm jacks, i don't have anything with XLR jacks, yet.
out-v3

https://befaco.org/docs/Out/Output_V3_Schematic.pdf

now i'm trying to build a "thing" to convert line level to mic level ... so my camera can record the audio as it has a mic input and doesn't get destroyed. the producer of the camera tries you to sell a 650€ adapter.

image_hp-ecm-ds70p.jpg

Sony ECM-DS70P - Portable Stereo Condenser Microphone.
Electret Condenser Technology.

witch should be the same as ...
image.jpg

https://www.conrad.nl/p/microfoonkapsel-1-10-vdc-frequentiebereik100-hz-8000-hz-c9767ed423lf-302155?WT.mc_id=gshop&gclid=CjwKCAjw5Ij2BRBdEiwA0Frc9QG4L6VRnjbCIQI5TLXPBFctiBUPlSYmsu0aNbjS0lF3P-dzMEDWUhoCQ8oQAvD_BwE&gclsrc=aw.ds&tid=1578107505_66447429024_pla-356257857727_pla-302155&WT.srch=1&vat=true&insert_kz=8J

i haven't done any tests with a 3.5 mm jack into the camera and scope it.

the camera records fine, but you have to be quiet.
now i'm exploring a new area and i don't know much about impedance of the mic input .. and the neutric NTE10/3 transformer is on it way.








 
Natural said:
This can work, yes, but since you have the Neutrik xfmr, you should use it, as it is a better solution..

i wanna protect the camera witch is battery powered.
Don't worry about it.

i bought that Neutrik transformer in an impulse and i wanted to know if that type/model does the job.
Yes it does.

it's center tapped, being 10K on 1 side and 50K on the other.
Not exactly center-tapped. If it was, it would be 50k and 12.5k.

witch should i use?
Use the 50k connection.
 
Hi, there.

this is what i have soldered on prototype board.

but i seem to have distortion or noise, not that much on my camera, but a whole lot on my pc ... but i do need to make a new cable for the pc.

it looks like the transformer steps up between Black and Red, that why i soldered a 4m7.

also on the primary side it seams to pull hard and bug down the audio level a bit.

i also used the Black & blue + 3M3 resistor.

maybe it's the 10nF  ( C2 ) ... even if i unplug the synth from the jack, you see 1 bar in the audio meter.
i use WIMA capacitor.

the cable is mono core & shielded, but cheap 3.5 mm connectors.

in general, it works ok ... when producing sound, but ...

mt file size is 14KB ... it wont allow me to upload the file and it says the folder is full.
 
Natural said:
also on the primary side it seams to pull hard and bug down the audio level a bit.
That's because you're using teh xfmr the wrong way. the audio signal should be connected to the high impedance side and the low impedance side to the sound card.
 
abbey road d enfer said:
That's because you're using teh xfmr the wrong way. the audio signal should be connected to the high impedance side and the low impedance side to the sound card.

indeed, it was turned around.
:)
thanks alot

i removed the 4M7 and soldered the White wire directly to pin 3 of the 100K pot, the Yellow wire to pin 1 of the same pot and the wiper to the output jack.

as ...

Black = ground on the synthesizer side.
Red = from the + of input jack.

i connected Black & White via a 10nF capacitor and 10K resistor.  (i think, i saw some schematic do that ... when i started this thread)

what should i do with the blue wire?
i can't have that floating in the air!
if you touch it ... you can see it on the scope.

i still have lots of noise on the pc, but i used a stereo jack instead of mono jack, but work fine in the camera now.

 

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