New ribbon mic materials and construction

It seems we are having a nice dialog here while not many other folks are interested to participate   

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Yeah, glad to have it. You are very knowledgable in the field. I'll call you Dr. Marik Olson!
We do have 500 views. And where's PRR? Thought he'd have some astute observations. Did he get lost in the woods again? Did a bear eat him?

As far as termination, i'll look at silver particle pastes. I developed Silver and  nano carbon conductive inks a lot in times past.  We ultimately printed three square miles of mylar with the stuff over the years the patents were in force, and did a lot of work with contact resistance. I'll look at aluminum/silver interactions.

I guess it's all about punching through that oxide film, and preventing further growth.

There's this:
http://www.freepatentsonline.com/7430297.html
But I don't think they knew about this:
http://en.wikipedia.org/wiki/Gold-aluminium_intermetallic

I make my own and spent a few years to find what works, what sounds good, and what can be efficient enough to match the ribbon well... and I don't believe it is EI  .

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Hmmmm....something that starts with T? I'm all ears (eyes) but if it's something really really good don't publicly disclose it!

You know, someone mailed me a cheap chinese ribbon transformer to look at. Actually it seems fairly well made...it's nickel, with multifilar primary and such. EI though.Haven't analyzed it yet...need to throw in a voltage follower and switch in my generator so I can get near zero ohm output impedance. Right now it's 600. I could do kelvin measurements with that, but a few milliohm output impedance will be handier.
Wish I still had the Agilent analyzer I rented. Sent it back. $1200/mo rental is too much for me right now.


&^#%! Joined the LISA yahoo group to help me a little with the learning curve. I previously used GRAPE, but it can't do dynamic analysis. So I have to learn LISA. Unfortunately there is nothing in the group messages except porn spam.

Les

Marik said:

It seems we are having a nice dialog here while not many other folks are interested to participate

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Reading with great interest, please don't stop

Have built quite a few ribbon speakers (including the motors) and while the scale is very different some things are shared. Will think about if I have anything to contribute with...

Martin

Les,

I've been in the silver paste/silver nano game full time for about 10 years.  3 square miles is quite a bit.  Carbon, silver, contact resistance... sounds like membrane touch switches?  Who were you working for?  

Since there is clamping pressure involved, maybe the ACP model would work best.  Try some low dispersity submicron silver in a high vapor pressure inert medium (mineral oil for example) and you can get some pretty low contact resistance while maintaining protection from oxidation.  I'd also recommend lapping the clamping surfaces with this approach.  

What temperature can an aluminum ribbon take before it goes goofy?  A little silver neodecanoate in a neodecanoate acid medium spread between the clamping surfaces and heated to 180-200C will decompose into bulk silver in situ and "weld" the surfaces together.  That might work better than a traditional PTF ink.  If copper or brass is involved, use alpha terpineol as the medium, since it wont oxidize the copper to the more stable copper neodecanoate and it is still a fair solvent for the AgND.

-Chris

-edit, uhhh....I mean low vapor pressure

I'm reading with interest too!

I did a bunch of experimenting with ribbons in the late '70's, but frankly I was way
out of my league while doing it.  Back then the information was simply not out there.

I mostly played with quiet front ends to eliminate the transformer. I tried large scale
transistors, as well as multiple parallel devices, not getting anywhere that I could
actually quantify as better than current technology.

I'm a high school graduate with curiosity intact, so I've poked and hoped in a lot
of different places, some have paid off, some not so.

This has always been a field of interest.

I too talked to Bob, he didn't clue me in much.

I've been in the silver paste/silver nano game full time for about 10 years.  3 square miles is quite a bit.  Carbon, silver, contact resistance... sounds like membrane touch switches?  Who were you working for?

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REALLY? Neat, Chris!
To explain, a couple of us from Shure got pulled away to work at a venture group of a large corporation.
It was an electrical contact house, but I decided to get into making custom audio potentiometers. We also made screen printable resistors, capacitors, thermistors, and the like. I was manager of research and development, and created all the inks and products.

As for the 3 square miles...I was puttering around with a "peel and stick" electronics kick I was on and came up with this:

http://www.patentstorm.us/patents/4931627/description.html

It went "viral" as they say. To date 500 million units have been produced. You might have them in your car!
It's kind of a big issue right now, because all the patents are expiring. They don't reveal the actual composition of the materials, or how to make the inks. That's in my head. So things may get stressful for me again.

Try some low dispersity submicron silver in a high vapor pressure inert medium (mineral oil for example) and you can get some pretty low contact resistance while maintaining protection from oxidation.

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Yes, I was thinking along those lines. At first glance silver is looking pretty good for aluminum ribbon termination. I got great results on copper and tin, but I have to check galvanic potential, intermetallics, and such for AG/AL. Again, it's looking good. Many low temp aluminum solders are AG/SN.

A little silver neodecanoate in a neodecanoate acid medium spread between the clamping surfaces and heated to 180-200C will decompose into bulk silver in situ and "weld" the surfaces together.

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That sounds neat. I'll have to read up on those compounds.

Martin and Dan, thanks for chiming in. Obviously, I'm contemplating a commercial product rather than DIY. I wanted to post some thoughts here, because this is where the microphone smarties are. I guess Bob C. did that too a while back.

This has grown out of a ribbon/dynamic specific preamp design I have done. I want to look at the microphones too, but really need to find some significant improvement to this old technology before I would consider marketing something. I doubt if the world needs another ordinary ribbon mic.

Les
L M Watts Technology

leswatts said:

It seems we are having a nice dialog here while not many other folks are interested to participate    

Click to expand...

Yeah, glad to have it. You are very knowledgable in the field. I'll call you Dr. Marik Olson!

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I wish I had 1/1000 of Harry Olson's knowledge about ribbon mics. One could only imagine if he had Neodymiums and our modern technology. Besides, what my computer spits out in a moment took tedeous and days long calculations, then...

leswatts said:

I make my own and spent a few years to find what works, what sounds good, and what can be efficient enough to match the ribbon well... and I don't believe it is EI  .

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Hmmmm....something that starts with T? I'm all ears (eyes) but if it's something really really good don't publicly disclose it!

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Well, indeed it is a T... (oroidal) tape wound one and no need to hide it, as it is all about core, its material, annealing, winding, and it is potted (watch out for uncle CJ, though). Also, very soon I will be offering it commercially (and also post in White Market here).

leswatts said:

You know, someone mailed me a cheap chinese ribbon transformer to look at. Actually it seems fairly well made...it's nickel, with multifilar primary and such. EI though.Haven't analyzed it yet...need to throw in a voltage follower and switch in my generator so I can get near zero ohm output impedance.

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Spare your time:

Pri: bifilar 16 turns, DCR=0.02 Ohm, L=1.52mH
Sec: 930 turns, DCR=76 Ohm, L=4.3H
Turn ratio 1:55

The inductance measured with HP 4274 digital LCR bridge.
The DCR with HP 3457 7 1/2 digits multimeter with Kelvin probes.

Emperor Tomato Ketchup said:

What temperature can an aluminum ribbon take before it goes goofy?  A little silver neodecanoate in a neodecanoate acid medium spread between the clamping surfaces and heated to 180-200C will decompose into bulk silver in situ and "weld" the surfaces together.

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That will need to be "locally" heated, as Neodymium magnets lose their magnetic properties already at some (IIRC) 100C. That temperature would melt many plastics, so the insulator will need to withstand that temperature.

Martin B. Kantola said:

Have built quite a few ribbon speakers (including the motors) and while the scale is very different some things are shared. Will think about if I have anything to contribute with...

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Hi Martin,

That's way cool. I started with electrostatics and built a few myself from scratch. I also was one of very few people at that time to service/recoat/reskin QuadESL57. Then I moved to ribbon speakers and built from ground up a few--planars and "true" ribbons, and now mics... Obviously, so far the sizes are going down, if one could notice  8) .

Dan Kennedy said:

I mostly played with quiet front ends to eliminate the transformer. I tried large scale
transistors, as well as multiple parallel devices, not getting anywhere that I could
actually quantify as better than current technology.

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Hi Dan,

Good to see you here in a microphone field. Yes, it is hard to eliminate the transformer (and there were a few threads here on the topic). The ribbons DCR/impedance is some 0.1-.15 Ohm, so we need lotsa very low Rbb BJTs and current phantom cannot give. With thinner foils and different size I could potentially make it up to 1 Ohm, or even more, but together with poor S/N ratio it is still quite low for low noise. Another solution would be using a smaller ratio interstage step up transformer, but then it defeats the whole purpose of the transformerless.

Best, M