Build Your Own 150 ohm XLR Plug for Testing Preamp Noise
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- čas přidán 9. 05. 2020
- How can you tell if the noise (hiss) you are hearing in your audio is coming from your recording environment or your preamp? Test it! All parts and gear used to make this video at kit.co/rayortega
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If you want to measure the amount of noise that your preamp is adding or isn't adding to your audio productions, you need to measure the noise from the preamp separate from the ambient sound in your environment which is being picked up by your microphone.
Making a 150 ohm resistor housed inside an XLR plug will allow you to plug into your audio interface and measure the amount of noise being produced by the preamp without being influenced by ambient sound of your room. This works because the 150 ohm resistor is equal to the resistance of the average dynamic microphone like the one I used in this video, the SM7B. So when you plug it in, the preamp acts like there is a microphone connected however there is no element to actually pick up sound from the environment and thus you get to measure only the noise that is within the device itself.
The way I use this is quite practical in that I'm less interested in the specs/numbers produced by the measurement for the purpose of comparing one preamp to the next and much more interested in knowing how much of the noise in my recording is being produced from the environment or microphone that I'm using. If the noise floor of the preamp is well below that of the noise when the microphone is plugged in, I know it's not the preamp that is contributing to my noise and that if i want to reduce the ambient noise I need to treat the space I'm in and not that I'm using subpar gear.
The build is quite simple and even someone like myself who hadn't soldered since he was a teenager was easily able to create this simple device.
Shoutout to / juliankrause where I first learned of this dummy plug for measuring preamp noise and who helped me make my own. Subscribe to Julian!
SUBSCRIBE: / rayortega
INSTAGRAM: / podcasthelper
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Parts to Build Your Own:
► XLR Male Connector amzn.to/2SRgrRA
► 150 ohm metal film resistors amzn.to/3bhOzMW
► Soldering iron kit (shop for the quality you desire, this is a cheap one but worked for me) amzn.to/3dnMSim
🎥 🖥 📱🎤 GEAR USED TO MAKE THIS VIDEO 🤘
► Sony a6500: podhelp.me/a6500kit1BH
► LENS: Sigma 16mm F1.4: podhelp.me/SigmaE16mmBH
► Rode VideoMic Pro podhelp.me/RodeVMP-R_BH
► SmallHD 5" Focus Monitor: podhelp.me/SmallHDFocusBH
► Transcend 65GB SDXC card for 4K podhelp.me/Trans64U3zon
► SmallRig Cage for Sony a6500/a6300 podhelp.me/smallriga65006300BH
► Aputure Light Storm COB 120D amzn.to/2mD7JFC
► Aputure Light Dome Mini amzn.to/2DEIj2v
► Shure SM7B microphone: podhelp.me/sm7bZon
► Adobe Creative Cloud podhelp.me/CC1yearBHdownload
*all links should be considered affiliate links. I encourage you to shop around for the best prices at the time you are viewing this. You can read my ethics statement via thepodcastersstudio.com/ethics. Thanks!
#audio #DIY #preamp - Věda a technologie
Nice work and big thanks for the shout-out! I'm looking forward for more preamp testing :)
Thanks, Julian! All the credit is yours. I hope it brings you more subs, there’s so much to learn on your channel and thanks for helping me make this!
Great vid Ray. Thanks
Been using this trick to troubleshoot broadcast console mic inputs and channel strips (mic processors) for awhile. It can save quite a headache when you suspect bad electronics.
Great to hear how you're using it, thanks for the feedback and for watching.
@@RayOrtega ... and thank you for presenting it, as many probably aren't aware of this handy device.
Watchin' you & Julian always inspires me to DIY and then I remember, I'm not a DIYer. LOL! I'm considering this soldering kit just in case I get the bug to do this.
This is the perfect project to start with. I hadn’t soldered anything since I was a teen and it was easy overall. I have made several of my own things but I don’t know that I would even call myself a DIYer so much as a tinkerer;) No time like the present, you’ll have fun!
Nice little gadget. I get to use my solder iron for once.
Even better if you just take resistor and insert into 2 & 3 female side of the cable directly, no soldering required. With resistor in my avg rms was -96db, with nothing -78db, and with mic -79db. This tells me my mic/cable/background is giving about 20db of noise.
As much as I love Julian, he didn't invent them. He did popularize them on CZcams though. Engineers and sound engineers have been using load testing dummy XLRs like these for a long time. I know a guy who has had a set of XLR dummys he made ranging between 10 ohms and 10K ohms and uses them for live events.
Thanks for teaching this proceedure! when testing the preamp with this, is it ok to test the preamp noise with phantom power ON too?
Noice
remember the solder should touch the pin not the tip of the iron - just like he did. I'm just mentioning it because it's important.
i was curious about balanced, wouldnt we just do it for both R+ and R- to shield, and shouldnt this be able to reduce noise as well, depending on dac construction
Good questions. I definitely don't build cables or do any engineering so best to ask is someone who focuses on the internals of audio devices like @JulianKrause czcams.com/channels/0HrD4cTsQpAZ8KK9jPzzGg.html this is where I learned about these dummy adapters for testing noise floors so I built my own based on Julian's model. Thanks for watching!
I'm just curious ... I built myself one of these, but the noise did not change in the preamp of the mixer I am testing when I tested without anything plugged in, as well as when I had my dummy mic plugged in. Is this sometimes the case? Interestingly, I mistakenly soldered pins 1 and 2 the first time and the noise was significantly reduced. Then I watched your video again and realized you said pins 2 and 3, so I re-soldered. After that, the noise lever did not reduce when I plugged the dummy mic in. What do you think?
It could be that. your mixer is compensating for not having an input like perhaps a noise gate. I've been digging through old emails and DMs cause I feel like I encounter this as well and I feel like I asked another engineer and that ended up being the speculation of what might be going on but I can't find anything to confirm. Did you turn the gain up all the way while recording and then insert the dummy plug? Maybe the change is barely noticeable but you might hear it at that level.
@@RayOrtega I recorded a sample with and without the dummy mic and analyzed them both with Adobe Audition's amplitude statistics. Both recorded with gain at 100% and level slider of input and master normalized at zero. Without dummy: average RMS amplitude is -47.82 db. With dummy mic: average RMS amplitude is -47.20 db. It's quite noisy to my ear, as well. It's a cheap mixer ... Audio 2000's AMX7361. I'm thinking about returning it for something else. I don't have a huge budget, but I could swing a little bit more. This mixer was $58. I can probably go up to $75-$100. I'm still researching to see what I find in this new price range.
@@michaelrapino4175 Yeah sounds like it's just a cheap preamp. My site is currently broken but you can still see the content, check out this 'sub $100 mixer shootout' I did awhile back thepodcastersstudio.com/sub-100-mixers-shootout/ also if you don't need a mixer but instead could use an audio interface, the Scarlett series has some nice preamps, this is the 4i4 czcams.com/video/lidsMVrVG7M/video.html but the 2i2 can be found for around 100 amzn.to/3nf03Z3 or take a look at the Rode
@@RayOrtega I actually went with the Scarlett Solo.
@@michaelrapino4175 Very cool. Hope it works out great for your productions!
How to use it?
This is an example of what you'd use it for: czcams.com/video/2DXEBahqBz4/video.html
The less solder you use, the better. Trust me; I'm an engineer.
Ray, the Julian Krause link is wrong. It's like this: czcams.com/users/youtube.com/juliankrause and should be like this: czcams.com/users/juliankrause
Excellent video, btw!
How much to get you to make me one?
I don't think I want to go into the manufacturing biz 😉