Shure Sm81 Microphone Tear Down & Repair
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- Опубліковано 28 чер 2024
- In this video, the Dave repairs Shure SM81 microphones explaining the various components and their functions throughout the process. The engineer identifies mistakes made by a previous repair attempt, and successfully tests and repairs by replacing missing parts like the high pass filter knob and a friction ring to prevent unwanted movement. Additionally, he notes the importance of a proper screw replacement in alignment and identifying a 10 dB pad circuit that's responsible for reducing output. The host concludes the video by saying he will create more repair videos like this in the future.
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00:00 Introduction
00:34 Quick Test
01:27 Disassemble and Mic Pads
03:29 Remove internals
04:27 How the Pad Functions
05:45 Disassemble Mic 2
07:10 Fix the Rattle
07:52 Reassemble
09:45 Test and Overload
10:42 Outro
Learning to fix mics is one skill that few discuss on UA-cam. This is good stuff.
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One of my favorite mics for shiny metal things.
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No matter the subject , always enjoy your presentation style Dave , and always a subject worth learning , from your obvious extensive experience in Audio . Many thanks .
If “legendary reliability” can be mentioned for any condenser microphone, the SM81 would be it. I recall a Shure rep coming to my office at its release and - I am serious here - throwing it at a concrete wall to prove it. I later learned this was SOP for Shure reps at the time so Shure was betting big on this new product. He left me two for consideration and I looked them over really well for concrete scratches before accepting. Today, I have 13 of them in my stock and all 13 work, all the time. Unheard of.
One caveat is that it is the most wind sensitive microphone ever made. Only the $38 multistage foam screen will suffice for any outdoor use. Even air conditioning is a consideration when using without a screen. I don’t consider that a major problem. Those $38 screens are the only maintenance mine ever need, like an insurance policy that actually makes sense.
Good stuff and yes those are the SM58 of condenser mics. I was never that big of a fan to use them because they sounded hissiy or spitty on the top end with higher quality sound systems but on the club PAs they worked great
@@DaveRat I didn’t find myself in that club PA mix position but I can definitely hear what you mean, never adding high end to them. They’re a little zizzy for Shure (sorry).
I was always the guy in the truck and they were a welcome departure from dynamics. They excel at the job they are never given, as area mics in a large band or percussion section. I can’t think of anywhere I use them close in anymore. Tymps and a toy table are both nicely balanced by a pair of SM81s.
And always with the monster A81WS. They also work in quantity for audience hangs. We used to laugh ourselves sick with the thought of just driving the truck away on a shit live session, four SM81s at the very end of a mass of equipment about a quarter mile back, bouncing on the pavement. They alone, nothing else, would work perfectly at the next show.
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Good work Dave.
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That was fun to watch. Respect.
This channel is severely underrated. Thank you for the great content! Love from sweden :)
Awesome and thank you!
No Shake, Rattle, or Hum ; ) ...Awesome!
Great video!
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OMG tank you! Please do more like this!!!
Edit: are there any resources, possibly focused on live gear repair you would recommend? I've been in live situations where knowledge and some tools would have saved thousands of dollars and professional relationships
Thx
Tanks🎉
Love this. If you want to do another mic video, the RE20 seems to suffer from death rattle a lot. I use them on everything, and fear the day they will go down.
Maybe try this vid. ua-cam.com/video/FClhZX7wnAQ/v-deo.html
@DaveRat haha, I should have checked first, been a few years since I looked for a video on it. Awesome man.
👍🤙👍 Cool cool yeah I figured out a way to fix the loose vent cover underneath the diaphragm took me years to figure it out
@DaveRat And we are now forever grateful. I'm gonna watch the video and maybe pickup and as/is one off ebay to fix.
Awesome and let me know how it goes
Thanks, Dave - cool, cool, cool!
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@@DaveRat Repair an SM57/58 next?
Soon, will do
@@DaveRat What is the most difficult mic make/model you've ever tried to repair? Just curious.
They fall into several realms, difficult due to glue and foam and messy build ike the RE20, difficult as in fragile and complex like the akg d224, which are beautiful works of engineering art, and difficult as in confusing puzzles like the Shure KSM137 capsule disassembly which has a myriad of super thin stacked plates and microscopic pin that jumps out on a almost invisible spring.
I'll do some videos on them at some point
Hey, hey, hey!
you are awesome. do you know where i can find the xlr pin piece on line? or is it just any xlr piece?
Awesome video as usual Dave, but your overhead camera is a bit out of focus ;)
Yeah I shot this with a wide angle and a lot of the video is in the mirror. I will try and do a better setup next time I film in that area
💡akg 535 repair 🙏
Love the video Dave. One of my sm81s crackles when I use it. How much is it worth paying to fix, given that these guys run between $150-$250 used on eBay. Thanks
I've been thinking of getting a pair of these, what do you like to use these on?
Lol my hands are not a steady as they used to be so I take it to a genius like yourself who makes the magic happen but let’s be fair they SHURE do build a solid unit for what is one of the harshest environments. The tour.
About three years ago I was doing some routine maintenance on my (now vintage) AKG C451. I had some kind of brain fart and tried pulling the PCB out the wrong way. This resulted in the pulverization of the ferrite ring through which pass the leads from the capsule.
Sadly this part is basically unobtanium so my only option would be to try and glue the shards of the original part back together, which I have not yet attempted.
You can probably relate to the wave of horror that washed over me when I realized what I had done. Recaling the moment still makes me cringe.
How is the mic working without the bead?
I'm not familiar with that bead but typically they're just for rejecting RF and as long as you're not using the mic in a RF environment it may work just fine without it
@@DaveRat I'd tell you but I never reassembled the mic. I put all the shards into a bag and placed that and the rest of the bits back into its padded box where they've sat untouched for the last three years.
I originally thought to service it because I was troubleshooting a 60Hz buzz on the output. I thought I would check for corrosion on the contacts and PCB.
I agree that the ferrite bead is probably only for RF rejection I guess I can reassemble it and see how it works.
And hum or buzz on those is usually solved by tightening all the screws
@@DaveRat Okay, you've reignited my interest in this. I'm abroad for a couple of months but when I get back home I'm going to reassemble the mic and report back.
Awesome!
Hey Dave! Can I ask you a question about Pad's? I'll tell you what I'm kinda racking my brain on.
So, I just bought a used 1995 Lawson L47 Tube Condenser, a Cardioid only version, and with his Dual Capsule Multi Pattern versions, they have a -12 db pad built in on the power supply, but the C only version has no pad at all. So, I called Gene Lawson to ask if I could get a PS pad mod, but he explained to me that essentially the capsule would have to be a Dual Capsule, so it's not possible.
So, basically what got me thinking was that Gene Lawson said, though getting a resistive pad built into the mic was an option, he said that resistive pads, and PS pads are not really the same thing, and said that a PS pad will actually be more effective for preventing overload of the capsule. (that's the term he used anyway, whether or not it's actually to do with the capsule handling more SPL's before distorting I dunno)...
So, what I've been trying to understand, and either way, is how exactly a PS pad is working, because I'm guessing that since he mentioned that you need the other side of the capsule to actually be able to use a PS pad, that maybe it's actually attenuating at or before the capsule?; Though I don't know if it's even possible to attenuate the SPL before the capsule, but just curious mainly if you know what's different about it, and how it works exactly? Also, just to be clear on resistive pads(in the mic), so those are basically only preventing the preamp from overloading if need be right? Is a PS pad in that case preventing the Mic electronics, and or tube from overloading maybe, or does it actually have something to do with the capsule handling more SPL's before distortion?>
Thanks Dave!
A bit out of my knowledge realm but I do know that condenser pads are often capacitors run in series or parallel with the capsule, which is also capacitive.
This reduces the voltages sent to the mic pre.
Reaistice pads later in the circuit don't prevent overload of the initial circuit.
@@DaveRat Hey! Ohh okay I see, so it's working more with capacitance, as opposed to a resistive pad. Ya, I just know he was saying that those types of pads can be more effective, so I guess I was kind of intrigued about the differences, because the way he sort of said it makes it sound more like you can actually get more headroom on the mic/capsule level, or earlier on like you say, where as with a resistive pad, I presume if the capsule can'† handle the SPL's, the pad isn't going to do much hah.
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I would just put the capsule from the rattle one on the other one sounded better😂
Except the one that worked looked like hell and the one that was pretty had the rattle inside and the capsules were fine on both of them
Wow, that little penicil mike is almost 500€ off thomann 😅
I'll keep an eye out for some 2nd hand bargains... 😒 not that I need one or anything... I guess I'm a farty fart guy, I've got G.A.S 😂
I've seen alot of pencil thin mikes on videos from the 60s.
But thomann has got a toothpick mike (AKG CGN 99HL) for about 200€ 😅
If you ever feel the need to floss on stage 🤣
Thin mikes are elegant though, on vocalist.. almost a fashion statement 😄
😘 'PromoSM'