Ribbon Mic Material

[ajayHD]

I am planing to make a reasonably priced ribbon mic but i have a few questions.
1) What material is best for a ribbon mic? I have access to aluminium but it is very expensive so i found some other "metals"  including silver(more expensive), copper, and an alloy containing all of the above.
2) what is a good thickness for the ribbon?  i was going for 2.5 micron sheets but is 6 micron any good or is there better?
3) What step up ratio is optimal for the mic 1:37 or is the transformer even needed ?

 

[joaquins]

The final result of a ribbon depends on many things and how they combine, thiner foils usually end in better HF response but the actual contraction of the body and magnets also affects it.

You definitely need something, there are some active ribbon mics but I thing they use even higher turns ratio transformers. The problem is the ribbon is quite low impedance, about 1Ω, probably less, with that impedance the level is so low any mic pre will amplify it enough and the SN would be really bad because they are designed for something closer to 150Ω driving impedance, so you need to rise the level to adapt for that.

I have no experience building them for myself, I read 6µm is quite thick usually, but much more easy to use, so you probably will want to start with that till you get more confident. I know some guys who built a mic which you could swap between different capsules and output stages, I remember a few transformers, I don't know if they have any active option but that wouldn't be a problem. They connected the parts with their own connectors, build on acrylic with magnets to hold them in place and cooper contacts.

I never got the parts necessary to build any, the foil is one of the harder things to get, here is impossible and have them shipped to here is quite a problem. I don't know about alloys but you probably want to start with the cheapest because you probably are going to screw some before you get it going... I've seen even thiner aluminum foils online but I read they are more trouble than anything else and not much better than 2.5µm.

If you can get the parts start building, there was a calculator online which helped to calculate the response from a few mechanical characteristics, like magnet size, foil width and thickness, corrugation, etc.

Good luck and keep us posted!

JS

 

[ajayHD]

Thanks for the reply. I think i might go for the aluminium foil as the other ones are magnetic and will complete the circuit with the magnet. And i found a good deal on 2.5um foil (£14) and it is a fairly large sheet. The transformer i will use will have a 1:36 ratio and is the most expensive part on the list. Hopefully can try this out soon.

 

[joaquins]

To try the capsule you could use a mains transformer, it won't be the best transformer and you won't get the best out of the capsule but you can try it out. You want something with high turns ratio, maybe a 5V transformer or something like that, use the smallest you can get in size and voltage. Connect the secondary to the capsule and use the mains winding as output. Don't wait any good HF response from it, but it will work.

JS

 

[abbey road d enfer]

I am planing to make a reasonably priced ribbon mic but i have a few questions.
1) What material is best for a ribbon mic? I have access to aluminium but it is very expensive so i found some other "metals"  including silver(more expensive), copper, and an alloy containing all of the above.

The choice of material is guided by the ratio between conductivity (inverse of resistivity) to density. It turns out that aluminium is hard to beat in that respect.

3) What step up ratio is optimal for the mic 1:37 or is the transformer even needed ?

A transformer is indeed necessary. In order to optimize a solid-state head amp, it would need to be operated at about 10 A; to my knowledge, no one has succeeded in making it usable.
Your 1:37 transformer would present an output impedance of about 2k, which is acceptable for driving directly a solid-state stage (it would need to be optimized for that), but not for driving a standard mic preamp with a typical impedance of 1.5-2k.

 

[ajayHD]

one more question. Would i need a pre amp (or mixer) for the mic to work; can't i just use an xlr to 3.5 jack with just the transformer?

 

[abbey road d enfer]

one more question. Would i need a pre amp (or mixer) for the mic to work; can't i just use an xlr to 3.5 jack with just the transformer?

What is your recording device?

 

[ajayHD]

well i would like to simply get a XLR to 3.5mm and plug it into my pc  and record using adobe audition

 

[abbey road d enfer]

well i would like to simply get a XLR to 3.5mm and plug it into my pc  and record using adobe audition

You should not need anything else; you may not have loads of gain but for close voice miking it should be ok.
Now you want to check there's no DC on the 3.5mm jack. Many soundcards have PiP capability for powering electret mics; you should turn it off.

 

[ajayHD]

well i would like to simply get a XLR to 3.5mm and plug it into my pc  and record using adobe audition

You should not need anything else; you may not have loads of gain but for close voice miking it should be ok.
Now you want to check there's no DC on the 3.5mm jack. Many soundcards have PiP capability for powering electret mics; you should turn it off.

OK thinks for the info and all the help from everyone i hope to get started soon. And i think i can turn down  the gain in the program, no sure if it will work. Also will i have a lot of background noise and if so is there a way to combat that  other than to lock myself in a closet for 3-4 hours.

 

[Whoops]

well i would like to simply get a XLR to 3.5mm and plug it into my pc  and record using adobe audition

You should not need anything else; you may not have loads of gain but for close voice miking it should be ok.
Now you want to check there's no DC on the 3.5mm jack. Many soundcards have PiP capability for powering electret mics; you should turn it off.

No you can't connect to the 3.5mm mic in of you cheap PC sound card because there's DC on that jack.
Those inputs are made to power Electret Condenser mics, as the electret is the principal used in the normal and simple Computer mics. Normally is 5V. And most often than not you can't turn it off.

What you can do is to buy a simple USB soundcard with XLR mic input, And always have the Phantom Power (48V) turned off.

 

[Whoops]

If you want to build a DIY Ribbon Mic I recommend buying Kits or parts from this websites:

http://www.diyribbonmic.com/

http://www.diyaudiocomponents.com/diy-ribbon-mic

 

[joaquins]

well i would like to simply get a XLR to 3.5mm and plug it into my pc  and record using adobe audition

You should not need anything else; you may not have loads of gain but for close voice miking it should be ok.
Now you want to check there's no DC on the 3.5mm jack. Many soundcards have PiP capability for powering electret mics; you should turn it off.

No you can't connect to the 3.5mm mic in of you cheap PC sound card because there's DC on that jack.
Those inputs are made to power Electret Condenser mics, as the electret is the principal used in the normal and simple Computer mics. Normally is 5V. And most often than not you can't turn it off.

What you can do is to buy a simple USB soundcard with XLR mic input, And always have the Phantom Power (48V) turned off.

You could add a cap in your circuit to block the DC, that's not a problem. The gain I guess it might will since most ribbons are quite low sensitivity, so that may be a problem. A good preamp will be nice to have with this, of course if you only are going to use it with the ribbon you could left a few parts out, like phantom power network, input coupling caps, probably input pad wouldn't be needed either. So you end with a simpler mic preamp, green pre could be a good idea, and you can find the boards here to build it, few transistors, a couple of opamps...

JS

 

[ajayHD]

well i would like to simply get a XLR to 3.5mm and plug it into my pc  and record using adobe audition

You should not need anything else; you may not have loads of gain but for close voice miking it should be ok.
Now you want to check there's no DC on the 3.5mm jack. Many soundcards have PiP capability for powering electret mics; you should turn it off.

No you can't connect to the 3.5mm mic in of you cheap PC sound card because there's DC on that jack.
Those inputs are made to power Electret Condenser mics, as the electret is the principal used in the normal and simple Computer mics. Normally is 5V. And most often than not you can't turn it off.

What you can do is to buy a simple USB soundcard with XLR mic input, And always have the Phantom Power (48V) turned off.

Ok thanks for that info. I was going to buy that is the 3.5 to XLR didn't work.

If you want to build a DIY Ribbon Mic I recommend buying Kits or parts from this websites:

http://www.diyribbonmic.com/

http://www.diyaudiocomponents.com/diy-ribbon-mic

And i did find those but they are ridiculously more expensive compared to the one i'm building. mine will be £50-70  there is £230 ish

 

[ajayHD]

Also is it 100% necessary to have a preamp if i am going with the usb XLR solution?  I'm only going to record my voice at close range.

 

[joaquins]

If you get a usb device which already has a preamp you shouldn't need it. What I was referring is with a nice mic is good to have a nice preamp, you don't need it to get it working but you could keep that project in mind for when you have the time and want to get your setup a bit better.

JS

 

[ajayHD]

If you get a usb device which already has a preamp you shouldn't need it. What I was referring is with a nice mic is good to have a nice preamp, you don't need it to get it working but you could keep that project in mind for when you have the time and want to get your setup a bit better.

JS

Thanks for clearing that up for me i'm going to try it without one at first and then in the future get one

 

[Biula]

The final result of a ribbon depends on many things and how they combine, thiner foils usually end in better HF response but the actual contraction of the body and magnets also affects it.

You definitely need something, there are some active ribbon mics but I thing they use even higher turns ratio transformers. The problem is the ribbon is quite low impedance, about 1Ω, probably less, with that impedance the level is so low any mic pre will amplify it enough and the SN would be really bad because they are designed for something closer to 150Ω driving impedance, so you need to rise the level to adapt for that.

I have no experience building them for myself, I read 6µm is quite thick usually, but much more easy to use, so you probably will want to start with that till you get more confident. I know some guys who built a mic which you could swap between different capsules and output stages, I remember a few transformers, I don't know if they have any active option but that wouldn't be a problem. They connected the parts with their own connectors, build on acrylic with magnets to hold them in place and cooper contacts.

I never got the parts necessary to build any, the foil is one of the harder things to get, here is impossible and have them shipped to here is quite a problem. I don't know about alloys but you probably want to start with the cheapest because you probably are going to screw some before you get it going... I've seen even thiner aluminum foils online but I read they are more trouble than anything else and not much better than 2.5µm.

If you can get the parts start building, there was a calculator online which helped to calculate the response from a few mechanical characteristics, like magnet size, foil width and thickness, corrugation, etc.

Good luck and keep us posted!

JS

For a 20-18.000 Hz capable motor you need a 1 - 1.5 microns aluminium...

 

[gyraf]

Why would you claim that, Biula? References, explanations?

(byw, you're replying to a 9 years old thread..)

/Jakob E.

 

[Biula]

Well, RCA vintage mics use indeed a 1.5 micron foil... my lab have processed many of them in over 20 years of activity... for my modern models, with neodymium magnets and a slimmer mechanical construction (hence, an higher top end limit of 22 kHz) I use a 0.6 micron foil.