The BM 800 Conversion

[@Magnulus76]

These Chinese mics are actually clever designs. Nothing is over-engineered. I wouldn't say they are suitable for high end music recordings necessarily, but they are fine for podcasting or streaming. The lack of rubber bumpers I think is explained by the fact the microphone body is intended to use with a shock mount.

[@SoundSleuth]

The components I am replacing the internals with are suitable for high end recordings. Thats the cool part. I have used these bodies for many microphones, never actually fired up one with the original parts. I can tell you they vary pretty extensively every time I open one up.

[@noahcwb]

Perfect timing on this video! After watching "diy perks" video on the mic he made a month ago i wanted to try my hand at making my own with a custom enclosure, but i wanted xrl mic, not usb. Once the capsules are back in stock I'm going to buy the parts needed. I do enjoy soldering so i might go for the diy option on the pcb, but I'm not excited about sourcing all the components.

[@SoundSleuth]

Excellent. I have been in touch with Matt from DIYPerks. He is sending people that want XLR mics my way. Interestingly he said he watched my build videos in detail before doing his. Which made me happy! Man, his is a work of art. Mine is well, a great sounding mic that you can actually build!

[@Mbee16]

Hi there. Thank you for this! I saw a 3D print file for a capsule holder that will make it end addressable.. Do you think it will work as well as an end address?

[@SoundSleuth]

Yes it will!

[@Mbee16]

@@SoundSleuth Thank you so much! I think it will be a bit easier to mount and position as an end-addressable mic.

[@joshuacabrera7462]

Thanks for this guide, I used the Jli 3412 for my microphone capsule along with the assembled pcb instead of the 2555b. Still sounds great though.

[@SoundSleuth]

Cool! I want to try that capsule

[@petercornell2002]

Great project Jules! On my list...

[@SpartanJoe193]

This is good actually because I am planning to exactly this when I buy a spare capsule.

[@SoundSleuth]

It is an excellent mic! You will like it.

[@SpartanJoe193]

@@SoundSleuth Indeed. I am buying a BM800 myself (with the 16mm diaghragm and big bpard that is) then buy a capsule.

[@raptakisk.9983]

Nice Jules, A project with Primo EM200 or relevant, with a Balanced FET preamp would be great also

[@fastunovaudio]

It seems I'm not the only one who dreams of seeing the development of Jules with Primo capsules )

[@KleyDeJong]

Awesome video, thanks for posting. I'm going to try my hand at this in one of the cheap chinese condensers I have lying around.

[@charls.the.composer]

Yeeees, more DIY in your chanel pleaseee!!

[@fate4538]

Hello I am wondering what cable I use for the XLR to board connections. Thanks!

[@badmiddens]

I'm wondering if this Alice circuit would pair well with an RK47 style capsule?

[@SoundSleuth]

It would. It will bring out the characteristics of the capsule as the circuit is very low distortion.

[@josirleytavares]

Vc tem o link dessa cápsula. Parabéns pelo canal

[@SoundSleuth]

www.jlielectronics.com/microphone-capsules/

[@vipover8558]

I have a bm800 with a dynamic capsule and I bought a condenser capsule and installed it instead of the dynamic. I tried it on v8 and it didn't work, so what is the problem?

[@SoundSleuth]

I need more information to help you. I’ve never seen a dynamic capsule in a BM800. As those don’t need any active electronics. I would need to see pictures and some more info.

[@vipover8558]

@@SoundSleuth I solved the problem with a transistor I extracted from a dynamic capsule

[@joedoe3446]

Is there a way to turn the cardioid mic capsule into a super cardioid ?? thanks (:

[@SoundSleuth]

Not without using a hypercardioid capsule. Ill look around and see what I can find.

[@BUPETA3351]

Great as usual. Could you do a version of your opaAlice with hf filtering, for use with k67 capsules. To get that u87 deemphasis response?

[@SoundSleuth]

I'll look at this. The OPA is so clean I usually EQ in post, if it needs it at all.

[@Qimchiy]

Hey i want to try this but with a 34mm capsule from JLI. Any recommendations?

[@SoundSleuth]

The TSC-1 or the JLI-103 you will need the hex inverter also for bias voltage. They are amazing microphones

[@talcandturnips]

Do you know if there's an equivalent source in Europe for the capsule? thanks!

[@SoundSleuth]

We are working with Micbooster to carry them (they are in the UK) And I am working with LOM to possibly carry them as well.

[@talcandturnips]

@@SoundSleuth That's awesome! I will definitely be buying some when they are available.

[@KurodaMasahiro]

Thanks for the tutorial, that looks like an easier alternative than diy's perk version :D !

[@SoundSleuth]

It is easier to do and it works with phantom power, which was my goal. The DIY Perks one is great, looks amazing but is USB-C interfaced. Great for direct into PC but not if you want to multiple mics.

[@KurodaMasahiro]

@@SoundSleuth I ordered 3 BM-800 and was surprised upon receiving them that the ones i got seem to be fully made of plastic and not metal (beside the mesh), do you think that would be a problem when building the mic (for grounding reasons maybe ?) Thanks !

[@SoundSleuth]

@@KurodaMasahiro I would send those back. I know Neewer ones are metal. Look for the Neewer BM800 on Amazon www.amazon.com/dp/B00XBQ8UGG

[@ckmoore101]

DIY perks one is unnecessarily complicated. Was really just a flex of ingenuity on his part. Job well done, but certainly NOT a project that really has value in duplicating. Plus, his totally disingenuous claim of $30 in parts..... I started the journey of replicating it, but abandoned after the BOM total exceeded $200.

[@fastunovaudio]

What do you think if there is 1.5-2 meters of cable between the capsule and the preamp board (that is, the capsule and the preamp will be in different cases) will it be OK? Roughly speaking, I would like to use the JLI-2555 or JLI-3412 capsule as a Boundary Microphone (something similar to the Sanken CUB-01), and place the pream in a separate case.

[@SoundSleuth]

I would use the TSB2590 (with built in FET) for that. The input impedance is 1 gig ohm on the preamp board so I dont think it would like 2 meter run between.

[@fastunovaudio]

@@SoundSleuth Please tell me, is JLI-3412 at all compatible with OPA Alice - Single Channel? I would like to experiment in the future.

[@SoundSleuth]

@@fastunovaudio yes. Any capsule without a FET in it JLI165, 2555B or the one you mention.

[@fastunovaudio]

@@SoundSleuth Thanks)

[@3dlearning453]

Any idea when surface mount PCB for the single channel will be back in stock?

[@SoundSleuth]

Ill check, I thought they were.

[@sashabagdasarow497]

What is the PCB circuit built in? Why does it need one?

[@SoundSleuth]

It needs an impedance converter to bring out the signal from the condenser capsule. See this: www.instructables.com/OPA-Based-Alice-Microphones-a-Cardioid-and-a-Figur/

[@impo64]

The cost of components here adds up to around 70$ with shipping, which is roughly the same price as a new AT-2020 from Amazon when it goes on sale. I've not done any DIY mic stuff in the past, would it be worth it to build this one in my current BM-800 over purchasing the AT-2020? I'm not sure if microphones is one of those things where building a 70$ one yourself will give a benefit over buying a 70$ one pre-made or if it's one of those things that won't give much of a benefit and is more just for fun.

[@SoundSleuth]

I personally think so. They are on par with a CAD E100. It is a great mic

[@NoNeNoNeNoNe134]

I just made this conversion, however I get horrible buzz while I touch microphone body.

[@SoundSleuth]

Look here: www.jlielectronics.com/content/TroubleshootingOPA-Alice%20MicRev1.pdf

[@WombRaider-s3j]

Hi sound sleuth i have a question. Will this exact bm80p that you made work if i plug it intro my laptop or phonr or is a phantom power preamp mandatory. Also fi i made serena (the one with OPA Alice abd Dc to Dc hex conv) will that also require a preamp?

[@SoundSleuth]

@WombRaider-s3j Yes, both of these require a mic preamp or USB interface that supplies P48 phantom power.

[@WombRaider-s3j]

I got one of those small FET electrets to work immediately by plugging it in my laptop via aux will this really not work probably with insane 80db gain ? (Btw its absolutely amazing how fast you respond thank you)

[@WombRaider-s3j]

Also if i am going to do this is it worth spending more on the capsule and also the hex converter or will this be god enough for anything not professional

[@WombRaider-s3j]

Sorry for replying again but i will be buying the fake bm800 just for the body will the v8s crappy soundcard provide the phantom power or something close to it to power it if it doesnt work immediately? If it can i will try to inprove the soundcard or at least make a simple preamp from it

[@joshuacabrera7462]

Would a ceramic capacitor suffice for the XLR connectors with A 50vdc rating?

[@SoundSleuth]

Yep!

[@roberthorniacek4559]

question would the JLI-RK47 work better in this build?

[@SoundSleuth]

It will! You will need to add a voltage bias generator for the capsule. This will work www.jlielectronics.com/diy-accessories/dc-dc-hex-inverter-pcb/

[@narberiuss]

@@SoundSleuth thanks for answering this question! Would be interested in seeing/hearing this build if ever.

[@_der_pinguin_2463]

Hi i have a question. Why do you need phantom power for a dynamic capsule. Isnt this circuit for condensor Capsules. I am just wondering because im thinking about building this.

[@SoundSleuth]

It is actually a Condenser Capsule. It is Electret so it doesn't need bias voltage. It does need an impedance converter and drive electronics to get the signal to the Mic Pre.

[@pierpa_76pierpaolo]

How do you test the capsule if it works before you assemble it? With the ohm scale, it is not detected like classic capsules. Here you have to have a capacimeter (pF) .... . Is there something to do a quick test? Thank you very much.

[@SoundSleuth]

The best way woudl be a capacitance meter. SHould be 30-70pF. That is a small value and not easy to measure. Quick would be ohmmeter showing open circuit and not shorted. With that said I have only have one issue and that was an internal short. That was over many years of this and the vendor replaced the capsule.

[@pierpa_76pierpaolo]

@@SoundSleuth What do I do now? I don't want to change pcb like you did! I want to try replacing the 13mm capsule (it makes too much noise and sucks) with this 25mm condenser one. Will it work or not? Tomorrow I'll take apart the old stand and glue on the new capsule and see what happens. What a stress these microphones need an electronic lab to test them best.

[@SoundSleuth]

@@pierpa_76pierpaolo You are heading out into unknown territory. Some BM-800's have Fet based capsules some do not. At this point you are not replicating my build so I cant tell you how it will come out. Try it and see.

[@Catapou]

Hi, that board looks incredible and i went to that stor to buy one for me... (1st time trying to mod this kind of thing) anyways... i live in Europe so the board isn't expensive but the shipping is 3 times the price of everting else combined, I would love to buy it still but i don't know how at this point. Thanks!

[@aleksanderpuopolo9611]

Great video, just wondering if TSB-2555B would work and how they compare (are they the same capsule?) wondering because of shipping costs.

[@SoundSleuth]

Yea it is.

[@Chinhnguyen0497]

Are there any good capsules? I can't buy it at my place, I found a seller but the company in China they don't retail

[@SoundSleuth]

Where do you live? There may be other options

[@kaiserneko12]

does this need phantom power?

[@dj4mc]

Yes, that is what powers the circuit board we are putting in the BM-800

[@Elijah-Peterson04]

Hello, I have a small question. I'm really new to microphones and circuits and I'm using this build to kick start my experience with microphones, why are we replacing this board with the board already installed in the bm-800? Is it for sound advantage or is it necessary? And if so why?

[@dj4mc]

We are replacing it because the new one performs far better, When you are done this is a world class microphone oon par with pones costing $4-500 bucks. See my full write up for more details: www.instructables.com/OPA-Based-Alice-Microphones-a-Cardioid-and-a-Figur/

[@gRosh08]

Well Done!

[@viniciovp4ever]

Is it possible to put a dinamic capsule in it?

[@SoundSleuth]

Yes. However then you don’t need a PCB or phantom power. Not sure where to source those.

[@johnweiss6335]

Whoa, this video has basically all I need for my project. I was actually looking to upgrade a cheap mic with a 2555 capsule and wondered what I was going to need. I hope I'll understand the process of building the PCB. Quick question: aside from phantom power, do I need to provide an audio interface (a friend can get me a Behringer UM2), or does the PCB circuit take care of that? Conversely, if I go with the audio interface can I ditch the PCB? Thanks!

[@SoundSleuth]

You can get the PCB fully populated if you need to. Yes you will need an interface. That is what supplies the 48V to the PCB and interfaces the Mic to the Mac or PC

[@johnweiss6335]

@@SoundSleuth Thank you! I asked because I would need to import either the empty or the populated PCB, so I was hoping to be able to circumvent the need for the circuit. I'll probably lean towards building my own, given the circumstances. That said, OPA1642 (and similar) is basically out of stock in my country until 2023, and shipping costs from any country that still has stock are insane. I know that NE5532AP isn't recommended, but would it really sound that bad compared to OPA1642 or OPA1656? I was thinking on using it as a placeholder until new stocks arrived, and a PCB breadboard to hold it all together in the meantime, instead of making a proper PCB or buying it online. I'm assuming that would also have an impact on quality, but I'm hoping it won't be that great. Anyway, if the 5532 (or any other Opamp) is not entirely out of question, would I need to add anything to the circuit and/or modify the existing one? Thanks again for everything :)

[@SoundSleuth]

@@johnweiss6335 please see the Instructable. The opamp has to be Fet Input for high Z, low quiescent current, and really low noise. 5532 nails the last one only. I’m looking for an alternate but no luck so far.

[@johnweiss6335]

@@SoundSleuth Same here. It doesn't help that I'm not very knowledgeable in this area, so it's kind of difficult to know what to look for. Closest I found (I think) was OPA2131: FET-input (no idea about resistance though, datasheet is not clear and/or I don't know what I'm reading), low quiescent current, but around three times the noise of 1642 (I don't even know if that's acceptable or not). Unless we luck out I guess I'll have to wait a whole year to build a mic at an affordable price lol.

[@johnweiss6335]

@@SoundSleuth Hey, it's me again! I was searching for alternatives and I just saw the shootout you did between different mics. Since both the USB-C and the OPA-Alice mics are, as of now, out of my reach because component shortage, my attention was drawn to the one with the 2590 capsule and the "simple P48" circuit. I've searched around a little, but all I can find are a few vague documents. Is it really just a resistor and a capacitor connected between the FET and the XLR? (I suppose then you connect the XLR to an audio interface like the Behringer or the Focusrite) What would be their values? Again, the documentation is kind of vague about that. If I were to use a 2555 or 3412 capsule, I suppose I'd need to attach a FET like the 2N4416 Matt used in his video, or an equivalent like the 2N4393. Would the resistor/capacitor values change? Would I need anything else? My plan would be to use a 2555 (if possible) with a P48 circuit until semiconductors are available again (or even place an order right now and wait for a year and a half) and then do the Alice conversion. Sorry for the long string of questions, but my options are dwindling and I'm a total noob, and feels kinda difficult to find useful info if you haven't been inside the DIY community for a while.

[@TheSlyMouse]

Nice!

[@AbdoZaInsert]

Great and a very helpful video. Quick noob question: Do you think an XLR to USB cable will work well with microphone after modding it to the JLI-2555 capsule ? or will it be underpowered ?

[@SoundSleuth]

If the XLR to USB interface (cable) supplies phantom power, it will work. The circuit in the mic is powered by the incoming phantom power from the interfaces XLR connector.

[@fmskaisergsaw5567]

@@SoundSleuth question from another noob can a modified Mic with the 2555 capsule and OPA Alice board directly be plugged into a PC via MIC In Audio jack to XLR? because i dont get that stuff with phantom power if im honest as it seems to exceed ~80V.. it wouldn´t damage the PC right? and honest question: is it worth it to buy a BM800 Microphone set (25€) with the OPA Alice board and capsule landing on a total price of ~140€? Or are there normal microphones that would compete with this in that price range? im Sorry, i´ve got no clue about all that, i only found the DIY Perks video, did some research for a refined circuit and landed on the easiest solution of buying a ready made BM800 to modify it with OPA Alice and a JIL2555 Capsule

[@SoundSleuth]

@@fmskaisergsaw5567 The Interface to the XLR jack provides 48V phantom power. The OPA board needs that. Most PC sound cards dont supply that.

[@fmskaisergsaw5567]

@@SoundSleuth thanks for the quick reply, was kinda still collecting my thoughts with some edits haha So i need some sort of pre-amp, gotcha though i just discovered that a condenser might not be ideal for the usercase it need a mic for.. :( anyway, your videos about the BM800 mods are appreciated