Easy way to check ribbon tension??

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Check ribbon tension or tension a new ribbon?

All ribbons with time stretch out or more correctly loose there tension. They are corrugated usually and those pleats eventually open with time. If you are building a new microphone and looking for answers as to how to tension a ribbon for the right voicing. You can just look in forums and on line or just guess. There are really nice plans available from Rickshaw Records google them. If you are trying to repair a manufactured mic that has problems. Well that is mic specific and should be handled by the people who do that all the time. They have special machines that tension the ribbon material (usually high purity aluminum foil). In the USA there are two very reputable ribbon repair people. Clarence Kain at ENAK Corp and Stephen Sank.

Good luck. :)
 
patosandia said:
hi! i want an easy way to check ribbon tension, does anyone know any? thanks!!!

That was covered by Zebra50 a few years ago. Make a search, or check in META.

Pip said:
All ribbons with time stretch out or more correctly loose there tension. They are corrugated usually and those pleats eventually open with time.

Do you have any data to support this claim?

Pip said:
If you are building a new microphone and looking for answers as to how to tension a ribbon for the right voicing.

The tension has very little to do with the voicing, but rather depends on the design parameters where specific motor, ribbon material and its dimensions, corrugation, accepted tolerances, transformer, etc., all affect the final result. 

Pip said:
Well that is mic specific and should be handled by the people who do that all the time. They have special machines that tension the ribbon material (usually high purity aluminum foil). In the USA there are two very reputable ribbon repair people. Clarence Kain at ENAK Corp and Stephen Sank.

First, the tension is done not by machine, as you say, but by hand. Second, while the people you cited have been in business for a long time, neither of them do use high purity Al, but rather (what they claim) NOS RCA material, which to my knowledge is Duralum--rigid Al alloy, which has low compliance and high mass (due to its high Cu content). It is prone to oxidation (up to a point being unusable in a matter of a couple decades), high resonance modes, and worse sonics, as opposed to pure Al material.

Best, M
 
I humbly defer to your definite advanced knowledge in this area. By the way you make a great product. I actually met you briefly at AES NY a few years ago.

I do not have any data to back up my claims but I do know that I have an RCA BK-5A that is in need of repair due to its age and exposure to some unfortunate shall we say gusts. The ribbon is not torn but definitely looks saggy shall we say. I also have had similar experiences with Coles mics. Oxidation is a fact of life and from my experience definitely proves the imperminance of everything ;D

As to the tensioning I got that from a converstaion with Clarence Kane many years ago regarding the repair of an old Reslo mic I have. He asked me if I new what the resonant frequency of the ribbon should be. This led me to believe he had ways of measuring this I don't. Granted an assumption on my part.

Thank You for the insight and the corrections.
 
patosandia said:
hi! i want an easy way to check ribbon tension, does anyone know any? thanks!!!

I saw a how its made episode were a worker had a signal generator and oscilloscope, it looked like he was exciting the ribbon with the signal generator to find the resonant frequency, though i really have no idea what im talking about.
 
sorry, i wasn´t explaining myself i guess.. i already corrugated the al foil. i re- ribboned a few mics, and they sound good to me, but what i want is to check resonant frequency, something like what abechap said.. sending a signal from generator and reading it with my scope or multimeter.. i have checked the META and didn´t find a more complete answer.

thanks again!!
 
correct me if i am wrong:

small value resistor in series with ribbon, oscillator across that string sensitive meter across the R, sweep sine and find (resonant) frequency where current peaks.
 
I could see the lowest resonance on a Fat Head simply by watching it's free air response to....air....in a quiet environment on a real time analyzer.  I'd expect even that crude observation would be useful. 
 
Here is that thread (first entry on a 'ribbon resonance' search under Zebra50 name):

http://www.groupdiy.com/index.php?topic=1810.msg22811#msg22811

Unfortunately, the pics with schematics are gone, but Shabtek is correct. Use 100 Ohm resistor. The only difference, connect it to a preamp before the meter, so you get a good signal to measure.

The EMRR methode is probably not as precise, but by all means very useful and gives a good indication.

Best, M
 
Hi!

I have just fixed those old links - I have changed servers a couple of times since 2004!

One thing to note is that the resonance may be quite broad, or on some mics the transformer is already starting to roll off at the low end. These can make the FAR frequency tricky to spot.

Cheers
Stewart
 
A note of warning, very often it is impossible to measure the resonant frequency with impedance method when the clamp contacts corroded, or a contact between clamp and ribbon is not good enough. This by itself leads to a significant raise of output impedance (1.5-2Kohm is not unusual in some Chinese ribbons).

Best, M
 
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