Видео

Thank you!

Yes, the normal 48V via the output connections, from a mixer or interface etc. mic input.

ps. There is more info about them on my web site - I added the link in the video description a few days ago.

@@RJTCyou updated you website!

Looks like this would make a great boundary microphone, I arrived here whilst looking for a module to power a Realistic PZM from phantom power but with this I could just build the whole thing.

@@Farmaceuticals Yes, that should work fine - all you need is the mic capsule face close to a wall surface / corner or a reflector plate. For the PZM 11, if you have one with the original circuit board fitted - they connect directly to a normal mic input with 48V phantom power, though using a passive adapter circuit.

Any mic designed for use with a normal XLR mic input on a mixing console or audio interface has to have a ground pin, for the phantom power return. The signal is the difference between the two output pins, and cancels ground noise etc. if used on a proper balanced input. I can't remember offhand how the unmodified U87 worked, I was not impressed with the electronics in it. I did get two of them though, and I do plan to do a comparison between that, the MXL V87 (which is excellent) and the converted U87 with a high quality capsule and my mod boards replacing the electronics. (I've just been too busy with work for the last few weeks to do anything much for my channel).

@RJTC The reason why I'm asking because the mic has an XLR input and a computer 3.5 output. I had the MXL v87 I can describe it as non-musical. I swapped it with a cinemag transformer, didn't help much.

@@StarOasis26 OK; a lot of the cheap Chinese mics come with an XLR to 3.5mm cable, which is crazy as the mic with the electronics to work with a 48V XLR input can not not work well on the 3 - 5V from a PC mic socket - it's pretty much chance if they give any audio at all! The work-around for that is to bypass the internal electronic and connect the electret capsule directly to the PC input, as that's what PCs are intended to work with! (That assumes the mic has a basic electret capsule with an internal preamp FET).

I've worked on machines with those, but never repaired one yet - what is the problem with it? If you search 6RA22 PDF, the user/installation manual is readily available, but there does not appear to be a public service manual for that. The 6RA22 catalog also has more block diagrams, that may help setting up or faultfinding?

Sorry but there is no excess - the large solder areas are deliberate bridges to connect between different stripboard tracks, a common technique for prototyping with stripboard. Removing that solder would remove vital connections and the device not work! However my PCB layouts for such as this are often perfectly symmetrical, just for the aesthetics! See the recent video on the electret mic adapter as another example.

Yes, it should do, with any normal two terminal electret capsule. I'll try to do the ebay listing for the built PCBs this weekend, if those are of use.

@@RJTC available in USA?

@@womplestilskin They will be on ebay, hopefully this weekend. I was intending to put them on immediately after that video, but work got in the way!

Do you have the two TFT display CS lines connected to different pins on the MCU, with no short between them? If that is OK, check the config file and look at the "Eye list" section; it should have a two-line definition, as with the last part in that section in my example config - that defines the CS pins for the left and right TFTs. With the default eye include, that should give left & right eyes on the two displays?

Look on Aliexpress for a BM800 - you can get one with a stand and clip etc. for £9.19 & free postage at present. Also a condenser mic capsule from £14.25 If you follow the very first input section parts instruction in the build sheets, plus my NPN output section, that should give pretty good results. Plus the power board as shown. I have also just done a small (~18 x 41mm), low cost virtually ready-built mod board dedicated for two wire electret capsules, which could be used as a kind of intermediate mod for a cheap mic, keeping the original capsule if it's one with an internal FET (or fitting a suitable one). I'm working on editing the video and documents for that now. The boards are ready-built other than the three transistors.

@@RJTC oh neat thanks

@@RJTC good news, I got a condenser cap coming rk87 model, the bm800, a saddle, the hardware, gonna see about your pcbs and the gribblies (cap, resist etc)

@@AdmiralStoicRum OK, I do include the two 1G resistors with the PCBs, if you get the option with the PTFE insulted pins, as people have had trouble finding those.

@@RJTC ordered! :)

Yes; from being a £10 toy before the mods, to comparable with the best mic I own, which has excellent specifications & very low noise.

There is no harm from wearing them. The greatest risks were in the manufacturing and application of the original material - many workers ended up with cancer due to ingesting or inhaling particles of the radium based material used. Also, watchmakers need to take some precautions when working on such watches; a dust mask, gloves and safety glasses/goggles until the hands and dial are stored in a sealed container and the work area has been cleaned to pick up any stray particles. (And similar precautions during reassembly, until the watch case is again sealed).

They still release gamma radiation and will still have a negative effect on your health

@@chip4039 Even if the movement and case provided zero screening or filtering, it appears from a quick calculation that you would have to wear that watch for almost 14 hours a day, every day of the year, before reaching the US government annual exposure safety limit. Filtering through metal is an established technique in such as X-Ray machines, to remove low energy photons. The higher energy ones passing through metal have a higher probability of also passing through flesh rather than being absorbed, so the actual absorbed dose should be lower to some extent that the emission through the crystal.

And no the mxl is still an electret capsule afaik and can be bought for very cheap on JLI Electronics website and is the best way to upgrade a cheap „sdc“ to that bigger design

Very true! I did mention leaving a few minutes for discharging after it had been powered.

Is that a joke? Please don't do that again. Discharge them safely. They last a lot longer than a few minutes and older ones may not have discharging resistors.

@@o0oBeckyWilliamso0o I always check the voltage! I do not rely on time alone.

Thank you!

They are well made! I think it only failed as it was left permanently powered for many years.

I'm not sure, as I have not dismantled it. I'll try to figure that out!

​@@RJTCmaybe use a jewelers scale and measure thrust?

I've not done part 8 yet, as I was expecting to easily remove the wrinkles from the recording discs - but no method I've tried so far has had any success. It seems the only possibility is to steam and iron one, but I'm concerned that could just destroy it (or the coating), so I've been putting it off in the hope of finding an alternate method.

The first car actually accelerates after the light changes, which is not very obvious in real time, but quite clear with the slow motion.

Hi, just about any decent NPN transistor that has suitable voltage ratings and gain should work OK. The 2SC2545 (or 2SC2546/2SC2547) would be excellent, as they are also very low noise & good gain, if you get any of those?

@@RJTC Hi, Just last night I finished mounting the BC546b and it sounds great! Very low noise and very good gain, thank you very much for sharing your research.

@@maramassaferro Great stuff! Thanks for letting me know!

OK, never heard that, thanks.

I've got to sort out the video for that yet, comparing the unmodded Aliexpress one to the rebuilt one, and my MXL V87.

That's from working next to a gaming PC for making the videos, rather than my music room!

For small drones, the foil / pouch cells with high discharge current are the ideal type, as they have the best capacity to weight ratio. You need the correct charger to suit the type, or a universal flight pack charger.

Thanks, valid point, I've added that in the pinned comment.

Apologies, I did not get around to doing the chapter marks at the time I posted these. Now added, so it's easy to skip the tedious parts. I did also post a short of opening the second pack to show the cells it contains, which was under a minute in real time!

People are going to hate. Thanks for getting the video out! Interesting watch

Thank you!

Thank you!

Hi Mike, I've not had time to try this properly with the RP2040; I did have a quick look and from what I remember, the error is to do with the SPI driver used, which was from one of the Arduino TFT libraries. The code will need adapting to suit the RP2040 SPI, creating or adapting an equivalent function.