Corrugating ribbons. Show us your rigs and secrets

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Kingston

Well-known member
Joined
Nov 1, 2005
Messages
3,716
Location
Helsinki, Finland
Hi,

I have several ribbon mics. I want the security of having optimal replacement ribbon material available at all times, and also to experiment with different ribbon sizes, tuning and corrugation of course.

I have just one problem: the corrugation rig.

I was thinking along the lines of this http://www.lkmusic.co.nz/ribbonfix.htm (scroll to the middle of the page) but it doesn't need to be such a hifi contraption. I've now been to several shops that sell plastic cogs of all kinds (for radio controlled cars, helicopters etc.). I also looked all kinds misc items (toys especially) that might have zigzag in the ballpark for this task. But I was not able to find anything suitable, not wide enough anyway.

How do you corrugate your ribbons?

Share us your ribbon corrugation rig tips and parts. What are your experiences with different corrugation methods and sizes? Plastic-cogs-galore webshops around? Links to any websites on this topic appreciated as well.

Mike
 
I guess that's why they're called secrets!

I did my first reribbon 8 years ago, and have done quite a few since then. My tips are...

Wait until you have plenty of time, and are calm and relaxed, and won't be interrupted. Lay off the coffee!

Be careful how you breath, and don't sneeze.

Use a magnifying lamp.

Here's how I measured the free air resonance of the mic (based on a forum discussion with Dave Royer)
z50RibFAR.gif


Vary the frequency from 20 to 200 Hz and look for the minimum.
 
he mike,

i was just thinking why not get a few cogs and glue/epoxy them together to get the right width. Alternatively i've seen a few shops on the internet that'll happily machine you a custom set of cogs for you.

greetings,

Thomas
 
hobiesound said:
get a few cogs and glue/epoxy them together to get the right width.

I thought about that...

But have you handled ~2 micron aluminum ribbon? It's so thin, that even the glue imperfection between the two cogs will probably rip it apart. Heck, breathing will rip it apart. Any little mistake will. Handling the ribbon is difficult enough already. The cog must be "perfect", and I can't see how a glue joint could be made that good.

Having custom cogs made sounds good, but it might be expensive.

zebra50 said:
Here's how I measured the free air resonance of the mic (based on a forum discussion with Dave Royer)
z50RibFAR.gif


Vary the frequency from 20 to 200 Hz and look for the minimum.

Here's how I measured and tuned mine, in a somewhat what less scientific manner:

1. tap the mic gently to get a nice "pt-trrrrr", or "ptoing-ttrrr" sound.
2. record that and measure the frequency in some audio editor tuner. If the editor doesn't already have a tuner, you can also calculate the frequency (cycle length divided by time).
 
1. tap the mic gently to get a nice "pt-trrrrr", or "ptoing-ttrrr" sound.
2. record that and measure the frequency in some audio editor tuner. If the editor doesn't already have a tuner, you can also calculate the frequency (cycle length divided by time)

Genius! I love it.
 
Lots of nifty plastic or teflon gears inside computer printers that have died or simply are too expensive to feed ink to anymore.
There are some videos floating around on the net about how to corrugate ribbons as well as installing and tensioning them.
My fingers aren't steady enough any more but I did make some ribbons in the last half of the last decades to try in RCA mics.
They worked but not as well as the factory installed ones.
 
Wow, great images! That Ekkehart custom made rig is bound to be quite expensive, but there are some great ideas there I'm totally going to do on mine as well.

On to hunt dead printers now.
 
Kingston said:
Wow, great images! That Ekkehart custom made rig is bound to be quite expensive, but there are some great ideas there I'm totally going to do on mine as well.

On to hunt dead printers now.

The Ekkehart's rig is in $1,800 range. His micrometer set on both, table and corrugator is cool, but it can be done much easier, using digital calipers. In fact, the micrometer set is not that necessary on the corrugator, which will greatly facilitate construction.

It is hard to find wide enough printer gears for bigger ribbons, and also, with narrow gears it is hard to adjust them. Throughout the years I had many corrugators and the main problem is ribbon skewing--the thinner the gear, the harder to adjust. That's why all professional gears are made wide. I have precision lathe, mill, rotary table, etc, so I machined my own gears.

If somebody needs help in machining parts, gears, or making entire corrugator you can contact me, but again, don't expect it to be cheap--many parts should be made with very high precision.

Best, M

 
 
This is one that I have tried and seems to work OK with a little care. I made it from brass garden hose fittings. The main challenge is to get the pressure right between the two halves. I just did this one as an experiment to see if I could use commonly available materials. I also have tried plastic hose fittings, but they are not as accurate in moulding.

Regards,

zephyrmic
 

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This is the one I tried with plastic garden hose fittings.

zephyrmic
 

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I have used thin foil from old paper capacitor, and tried it in an old ribbon mic I have. Seems to work well. Although that mic has very low output, probably due to old iron magnets that have lost their magnetism, from what I can tell. You can see some more pics on the micbuilders forum in the Photos section under zephyrmic's Ribbon Mic DIY. In that section, you can see Zephyr 55 ribbon mic I have had new for years. Nice mic. I think it was based on the RCA design. The Zephyr company no longer exists. One of these days I would like to make my own ribbon mic. At present I am working on some condenser mics from scratch, using TSB 2555A capsules. Initial listening tests suggest they sound good.
 
zephyrmic said:
This is one that I have tried and seems to work OK with a little care. I made it from brass garden hose fittings. The main challenge is to get the pressure right between the two halves. I just did this one as an experiment to see if I could use commonly available materials. I also have tried plastic hose fittings, but they are not as accurate in moulding.

Regards,

zephyrmic


excellent work!  very very nice !
 
So there I was minding my own business walking down the street and I walked past a garbage dump. And I found a beat up old printer!

Plenty of plastic cogs there. Actually two different gauges (or whatever the unit is for cog teeth size/type). Width is 6.4mm on both. Due to the probable ribbon skewing when it goes through them I realise it's only barely enough, but it'll have to do. I'm also slightly worried about the pressure between the cogs. Have to get all MacGyver with this.

I'll post pictures when I'm done experimenting with the cogs.

I still have to fashion a safe and accurate way to cut the sheets I have. I have a great knife for the job, but no glass yet.
 
mrc said:
If I may ask, where did you get those brass garden hose fittings?
mrc

In Australia, they are available at most hardware and garden supply stores. In fact, these brass ones came from a variety store that sells everything from China cheaply. Hope that helps.

Regards,

zephyrmic
 
Kingston said:
Plenty of plastic cogs there. Actually two different gauges (or whatever the unit is for cog teeth size/type). Width is 6.4mm on both. Due to the probable ribbon skewing when it goes through them I realise it's only barely enough, but it'll have to do. I'm also slightly worried about the pressure between the cogs. Have to get all MacGyver with this.

That was a good find. More modern printers use thinner gears. The easiest MacGyver (and with those kinds of gears might be pretty precise), would be securing one gear in a vise and placing the ribbon on top of it. You will need to use 1st and 2nd fingers of one hand as a guard.

Hold second gear in another hand right in the center (again between 1st and 2nd fingers), letting it turn smoothly. Roll the second gear on top of the first, sandwiching the ribbon. Do it slowly, making sure the ribbon foil stays straight--guard it as necessary. Try to keep the second gear as parallel to the first as you can. Don't put too much pressure, otherwise you can whether tear the ribbon or deform the material (and increase resistance).

Best, M
 
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