Mic preamp for dslrs from old camera adapters

 

With the advancement of technology, It’s quite common for perfectly functional equipment to become obsolete, and essentially worthless. As is the case with Standard Definition miniDV cameras. They may work, and the professional ones like the Panasonic AG-DVC30 still look the part, but they have been left behind in history.

Attached to the top of most DVC30’s is a unit with the model number AG Mya30g. Just what is the AG Mya30g? Well it is an audio pre-amplifier, allowing the operator to connect professional XLR microphones to the camera, and to allow control over those Mics. It can supply phantom power to two XLR microphones, and provides you with a range of settings for the audio.

Here you can see all the controls over the audio you get with the preamp, and they are all useable with this easy mod.

These features include:

Mic / Line switching – Line level is useful if you wish to feed the camera with a line level output from a mixer. Mic level is obviously for microphones. The original article I’ve used for reference says that this is the input gain of the interface.

Attenuation switch – Useful for cutting the level from a microphone that is outputting a high audio signal that is clipping at the input. This can happen when recording loud noises, or using very sensitive microphones.

+48v – This switch activates the Phantom Power to the unit. Many microphones require phantom power, and this allows you to activate this power.

CH Select – This switch decides the routing of the microphones. It can be a little confusing, but CH1-2 patches the audio from XLR input 2 through to both output 1 and 2. This is usually used to send the onboard shotgun mic to both channels of the camera. The CH2 option patches XLR input 1 to one output, and Input 2 to the other output. This is the option to use when you want to use 2 different microphones, for example, the shotgun mic, and a lapel microphone.

Output volume knobs – Embedded in one end are two little dials, that allow you to adjust the output level of the module.

Now, you can see there are a lot of features here that are missing from modern stills first DSLRs and Mirrorless cameras.

I had a thought when I came across some of these cameras, what if someone was to figure out how to utilise this old but still valid technology, to allow it to be used with modern cameras?

Well, as it turns out, I wasn’t the first person to have this idea. I came across the blog at monterdiy.net

http://www.monterdiy.net/adapter-panasonic-ag-mya30g-jako-mobilny-przedwzmacniacz/

It’s written in Polish, but thanks to the magic of Google, you can translate it well enough to get the idea of what is going on.

And He’s done a whole lot of investigation, and got a lot of very useful info, like the fact that the preamp module has it’s own inbuilt power regulator that can accept a voltage from 3.6 – 36vdc.

He has even posted the pinout of the connector that is wired to the terminal block is also shown.

Which makes it really easy to wire things up.

Here is my interpretation of the pinout for the connector.

 

You could wire everything to the existing cable, and not even open the box (that’s what I did to test if it would work), but if you want a neater solution, you could do as I did, and slice open the insulation to extract the wires, and connect power and audio to the now much slimmer cables.

Before I got too far into this, I cut the multi pin connector from the cable, and wired iti up to power and half a 3.5mm audio cable.

Choosing how to power the unit was one of my first things to decide on.

Thankfully, with such a wide range of voltage input, things are fairly easy. Pick a battery in the voltage range provided, and see how it goes.

In my initial prototyping, I chose to go with 4x AA rechargable batteries.

They give a nominal voltage of 4.8v, providing a decent amount of room for voltage drop as the batteries depleat.

Once I had wired everything up though, I decided to move to a Sony NP-F550 style battery mount. That allows me to use the same batteries that I have for my LED lights. For a battery mounting plate, I used the top off a cheap battery charger. It holds the batteries firmly enough (but not as sturdy as a more expensive locking unit), and you can buy the entire charger for around $5, versus $20+ for a proper battery mount.

The NP-F550 battery fits really well on the unit. You could get away with the even smaller batteries with ease I imagine

For the connection to the camera, I simply cut a 3.5mm audio cable in half, and used one half, wiring it up to the appropriate wires from the unit.

The biggest issue I have with this unit, is that it’s difficult to adjust the gain on the unit on the fly. The gain controls are so small and hidden away. I guess it means that they won’t be bumped, but it’s still a pain.

Once I had everything wired up and working, I needed a way to mount everything to a camera. I came up with a pretty neat, and basic solution.

Here is a shot of the mounting plate with the 1/4 30 to hotshoe adapter attached.

I cut a square of aluminium I had kicking about, and taped a ¼ 20 hole in the middle of it. For long term use, I think the sheet is a little thin, and the thread might pull out, but for this initial testing, it works great. A small cheese plate from Ebay might work better, and allow more mounting options.

Into the aluminium base, I screwed a ¼ 20 to hotshoe adapter, allowing the whole unit to slot into the hot / cold shoe of you camera.

Everything is held together with hot glue for now. Hotglue sticks well enough for now, and allows me to change things if I desire later. Epoxy, or working out how to screw the components together would likely yield better, more permanent results, but I like to be able to tweak things in the future, so I’m a little hesitant to cover it in epoxy.

The preamp allows me to really turn down the internal preamps and avoid that Canon microphone hiss.

Testing with both my Canon EOS-M, and EOS-650d has yielded impressive results. I can turn the mic inputs in the cameras right down, and use the preamps in the Panasonic unit. This allows me to minimise the effect of the noisy preamps on the recordings.

So, now you can see, I have a great little microphone preamp that was destined for the scrap heap, but is now very useful again, with features often seen in products worth hundreds of dollars.

There are a few features that I may like to add to the unit in the future if I can figure out a way to do them without too much cost or effort.

A way to monitor the audio would be very helpful. As my cameras don’t have audio out, or permanent onscreen audio display, it can be hard to keep an eye on the audio levels you are recording. Splitting the mic output, and sending it to a headphone amp and/or VU meters would give some ability to monitor audio, even if it is only a rough idea.

Another thing that I may investigate is adding a port to the NPF battery sled, allowing me to run other items from the battery – specifically, my EOS-M, who’s batteries are small and run out quickly. This would be fairly easy to do.

Here we have the neat little unit, ready for use!

And that is about it as far as this build goes. I hope you have found this interesting, and if I have left out any details, let me know, or check out http://www.monterdiy.net/adapter-panasonic-ag-mya30g-jako-mobilny-przedwzmacniacz/ to get further details from the source.

 

 

How to use a Rode Videomic ME on your DSLR or mirrorless camera with a 3D printed microphone mount

I’ve been playing with the 3D printer again, and I’ve printed a shockmount for a Rode Videomic Me, with an integrated shockmount.

I’ve made a video of the device, which you can see here:

The original version of the clip can be found on Thingiverse HERE. Note that this isn’t my model, I was just fortunate enough to find a model that fits what I was trying to do perfectly.

The clip turned out really well, But I had to add a small square of double sided foam at the bottom of the spring part, I can dampen the vibrations that were present in the clip without it.

Once you have the microphone, and the shockmount, you’ll need a cable that adapts from the smartphone TRRS, to your camera’s input, which is generally a stereo TRS 3.5mm input. Thankfully, Rode make such a cable -The Rode SC3 – which for mycamera, is a perfect length.

If you want to save a few dollars, you can search on ebay or your favorite store for a similar cable. You’ll generally find ones with 2 male jacks, one for the microphone, and one for headphones. Just use the Microphone one, and tuck the other end out of the way

Here are a couple of ebay links to the two mentioned devices. They are Ebay Australia links, and I’ll stat that I have no affiliation with either sellers.

Rode SC3 adapter cable (an Australian store, selling for $15aud):
http://www.ebay.com.au/itm/RODE-SC3-3-5MM-TRRS-To-TRS-Adapter-for-Smartlav-/272084989754

Cheap ebay adapter (an Australian store, selling 2 for $5.95aud):
http://www.ebay.com.au/itm/2X-Female-to-2-Dual-Male-3-5mm-AUX-Audio-iPod-MP3-Headphone-Extension-Cable/122446560653

This setup works really well, and now I can use the microphone on my smartphone, and on my EOS-M, or other video cameras.

I hope you find this interesting, and will come back again soon.

Ozito belt grinder to stand alone 2x48inch grinder

I started this blog post ages ago, and add bits to it occasionally. Now I’m almost happy with the way it runs, I figure I should post it up and let you all see it in all it’s hideous glory.

This story begins with a $69 bench grinder with attached belt grinder. THIS one to be specific.

This is the grinder from Bunnings.

 

There is nothing similar for close to this  money. However, of course, you get what you pay for.

To start with, its very underpowered. That was kind of expected, but I thought it might do. The biggest problem though was getting it to track correctly.

The tracking mechanism was horrendous, and it would take 10 to 15 minutes to get the thing to track right if you changed belts etc… and the pressed sheet metal parts would bend all the time.

I tried to use it as is, but fairly quickly started modifying it to make it suit my needs better.

 

Modifications Phase One – Simple tweaks

The grinder before any modifications

Here is the grinder before I begin any modifications on it

I began by modifying the grinder to work suitably with my needs, rotating the belt so it ran vertically, and adding a new work support that was nice and large.

A small template I made to make re-drilling the holes in the case of the unit easier

A small template I made to make re-drilling the holes in the case of the unit easier

 

The holes drilled in the grinder case. The slots you can see are the original mounting positions

The holes drilled in the grinder case. The slots you can see are the original mounting positions

Here is the grinder after the modification. Much easier to use.

Here is the grinder after the modification. Much easier to use.

This worked OK, but the issue of belt tracking still existed, so on went the modifications.

 

Modification Phase 2 – Fixing the tracking, and going bigger

Here is an overall shot of the grinder, now running the longer belts

Here is an overall shot of the grinder, now running the longer belts.

 

Here is a close up of the tracking system I make. Far from perfect, but it kinda worked.

Here is a close up of the tracking system I make. Far from perfect, but it kinda worked.

Now, I was getting sick of how hard it is to get the grinder to track right. the mechanism was so bad, it was almost impossible to get it to run right. So I set out to make a new tracking system, and while I was at it, extend the length, so I could fit the longer 48 inch belts.

The tracking system is made from angle iron, and uses some parts left over from the previous tracking system, mainly the tension spring.

Now, this tracking system is not perfect, but Its a heck of a lot better than the original system.

 

Modification Phase 3 – chuck everything out and start again.

Belt Grinder

OK, at this point, its hard to call it a modification, its basically a new grinder. All that remains of the original grinder are the drive and tracking wheels. They seem to be holding up so far.

I had a 400 watt electric motor from a pool filter pump I had kicking about, which I originally picked up to make a disk grinder out of. I noticed that its shaft is exactly the right diameter for the drive wheel of the Ozito grinder.

Using some scrap metal which I salvaged from a wall support from a CRT TV as the basis for this grinder, I’ve constructed a more traditional style belt grinder.

Belt grinder

 

This grinder now works much better than any iterations before it. It does still have its ideosyncracies though.

The gas strut I’m using is too strong, and puts way too much tension on the belt. Unfortunately, due to construction, I can’t move the location further down the pivot point, to reduce its leverage effects, as the main support gets in the way.

 

Modification Phase 4 – Further Improvements.

So at this point, I decided to change directions with the way I was doing the belt tensioning. I moved to a telescoping pillar style method, using vertical shaft of the grinder as the outer  motion point. It uses the same gas strut for tension, but this way it provides less force on the belt, and things run pretty nicely.

The grinder as it stood before receiving the wheel and platten update.

 

After that, I felt what was holding me back was the wheels on the grinder. The skateboard wheels I have been using have a slight taper in one direction, that makes keeping the belt straight a little difficult. I could try and correct the taper, but in the end, I chose to simply replace them with proper grinder wheels.

The wheels I’m using came from Ebay, all the way from Poland from THIS store  (no affiliation, just bought them from here). Being custom made for the purpose, they are a lot more solid, and are actually square compared to the slight taper the skateboard wheels had.

 

This is the wheel set that I bought for the grinder. Currently I’m not using the drive wheel.

 

My current frame for the skateboard wheel assembly wasn’t going to work for the new wheels, so I went back to the drawing board, and  started fresh. Some more scrap steel from the brackets and bits & pieces I had lying about, and I had a one piece frame, and I didn’t have to worry about welding bits of steel together in the same plane like I did with the original.

 

Laying out the new platten / wheel assembly

 

Getting things lined up on the new platten assembly

 

Here I align the work platform and receiver before welding it on.

 

Here is the grinder with its new wheels. I’m yet to mount the actual platten in this image, but you can see how it looks at least.

It’s been quite a journey from a crappy, overly cheap bench grinder with attached belt sander, all the way through to a slighly more powerful grinder that functions a whole lot better. There are things I’d change. If I were starting again, Ideally, I’d avoid the bench grinder all together, and just start with a set of the wheels I posted, a motor that suits the wheels and a nice pile of fresh steel. Its always good to use what you have lying around, but often you get nicer results by investing some money and doing things properly.

Now I’m fairly happy with it’s layout and operation, I’m happy to let the grinder’s evolution to rest here for a little bit. It’s working as well as could be expected, but there is always something else to tweak. What I want to do now is USE my grinder to get making some things, specifically a few knives.

And for you all that read though to the end, here is a video of me talking about the grinder, and it running:

Visiting my local maker space, and playing with 3d printers

So, Last night I payed my second visit to my local maker space here in Canberra, Make Hack Void. A couple of weeks ago, I came to chat about 3d printers, and this week I came in hopes to get hands on experience with the one they have at the space – a Lulzbot TAZ 5. I’d never had the opportunity to play with a 3d printer before, but had read about them in passing previously.

A few weeks back, my father was talking to me about 3d printers, and that his local Mens Shed was interested in possibly purchasing one to learn and experiment with. With this in mind, I began researching printers a bit more seriously, and I finally made the plunge to go visit Make Hack Void, as it seems like a great place to learn about such things without breaking the bank and buying a 3d printer myself.

Getting involved in MakeHackVoid has been on my todo list for waaay to long, so it’s nice to finally get a chance to visit.

All they guys I’ve met so far have been really friendly, and even though I’ve only been there twice, and I’m generally an awkward, shy person in unfamiliar places, I felt comfortable, included and at ease. I actually felt part of the place.

Anyway, back to the 3d printers. I bought with me a few models that I’d like to print, but starting with a fairly basic model that would print fairly quickly, and allow me to get things done.

The model I was printing was a modified version of this model:

https://www.thingiverse.com/thing:2234814

I modified the original print to remove the actual Lyre style shockmount for this print. It’s pretty basic, but it prints fairly quickly (this took about an hour), and lets me check the sizing of the clip, and cold shoe, as well as seeing if the arms are likely to snap in half as soon as I try and clip in the microphone. The model I printed is shown below, and I’ve uploaded it to Thingiverse at: https://www.thingiverse.com/thing:2497931

 

The Lulsbot Taz5 printed my first print fantastically. It was touch and go early on, when the long skinny clip arms came off the print bed, but damage was minimal, and the print kept going, all the way to completion, and I ended up with a very usable print.

3D printers are mesmerising to watch, and the Taz5 sounds like a happy little robot buzzing around the printbed as it worked away.

As I mentioned earlier, the print I did last night took about an hour to print. While it printed, we chatted about 3D printers, and some electronics, and I managed to snap a few pictures of the print in progress, as well as the settings we used:

Finally, once the print was complete I let the printer cool for a few minutes and then the print popped right off the print bed.

Once I got home, I  snapped a few pictures of the completed clip, so you can see the details of the print, and attached the mic to the camera, so you can see it in action.

So my first hands on 3D printer experience went better than I could have expected, and everyone at Make Hack Void are really friendly & inviting. I look forward to coming back again soon so I can have good chat with everyone, and play some more with the printer!

Rode Videomic me – Featuring me, and a little bit of the mic

For my birthday, my wife bought me a Rode Videomic ME, and I made a short little video about it for YouTube, so here you go:

The Videomic Me is a directional microphone for smartphones, that plugs into the headset port on most smartphones.

The port has a mic input, for hands free headphones, like the ones that would have came with your phone. Conveniently, people worked out a while ago that you can plug other mics into the headset port, and get better audio from your smartphone.

Step for sore puppy

Our dog Bella is about 9 years old now, and she has arthritis in at least her back hips, and I suspect her front ones are developing it as well.

So, my wife and I figured she needed some kind of step to help her get up onto her favourite chair, so this past weekend  I made her a step to help her get onto her chair.

All projects begin with some planning. Design wise, it’s pretty basic. It is just a wooden crate. Sketchup is fun and easy to use for sketching out designs like this. I began using dimensions from pine timber at Bunnings, but due to there being a surprise amount of timber needed to go into it, I decided to use what I could scrounge up around the house. Free is always good.

This is a rough cut and screw together project. There is no fine woodworking happening here!

Screwing sides together

Screwing sides together

In order to avoid bothering with trying to glue up a bunch of not completely straight pieces of timber, I went with screws. The strips of timber on the ends hold the two side pieces together. They are also decorative. Width wasn’t particularly important, and these were offcuts from ripping the timber for the thin strip on the top of the side.

On a side note, It can be a pain to rip a board that is already cut to length with a hand held circular saw, as the fence runs out of timber to guide it. It is easier to do if the board is longer than needed though.

Screwing the sides together

 

Sides done, now working on the top

 

 

Job done, Bella testing out the box. Apparently it makes a good pillow

 

For anyone interested in building something similar, Here is a picture of the sketchup drawing of my project. Please note that I made this to suit the timber I had lying around, and to match about 1/2 the hight of the chair, so if you are making this for a similar purpose, you may need to adjust your sizing to suit your chair, and the timber you are using. You could also turn this upside down, and it makes a fairly sturdy storage crate.

sketchup layout