Ribbon clamps noise figure

[Guest]

>what is the frequency of this noise? how would you describe it?
>I am curious and would like to hear more about this.

Tobi,
Simple white noise, like resistor 1 Ohm in series with 0.25 Ohm ribbon.
Bad degradation of noise figure.
But you must have good transformer and preamp and measure
noise via FFT and compare it to simple 0.25 Ohm resistor.
And you must know transformer noise properties to compute something.
For measure it, you must have shielded chamber.

 

[ToobieSnack]

xvlk

To solder Al to Cu thin wire: I use Al soldering liquid (HF+ethanol;

what does HF stand for?

Slightly wet Cu wire near the ribbon by that liquid and then use normal trafo iron and BISMUTH solder.

OK ...what is meant by trafo iron and BISMUTH solder?

Everything nicely soldered. That liquid must
be used in small quantums and have very agresive fumes (only two
contact soldered discomfort air in whole room)

sounds flammable too...yes?

thanks
ts

 

[Guest]

Hi, Tobbie:
[quote author="ToobieSnack"]what does HF stand for?
[/quote]
It is fluor-hydrogen acid. It destroys glass (SiO2) and
coround (Al2O3) also.
It is too strong alone. Mixture with water and ethanol is O.K.
You must deposit it in plastic bottle and use plastic capilars to
manipulate with it.
If you solder ribbon, it can not be NEVER in the contact with ribbon.
I put little of this liquid to near copper wire (must be thin and short)
and then solder the copper wire by bismuth solder. Ribbon was then atracted to the solder via capilary force.

trafo iron

soldering gun with snall piece of copper wire heated by strong current
generated by big transformer,

and BISMUTH solder.

BiSnPb Alloy, somewhat like wood s alloy used for soldering
of thermal protected resistors.

GOOD LUCK FOR YOU,
xvlk

 

[BYacey]

The whole problem is the fragile nature of the ribbon, and the toughness of aluminum oxide. Aluminum oxide is extremely hard - they make sandpaper grit and grinding wheels from this stuff. Perhaps there is chemicals that will eat through the oxide layer without destroying the ribbon. But is it really worth the gain? For years ribbon mic manufacturers didn't worry about this.

 

[bcarso]

I wonder if a hydroxide would be an interim step. Maybe do one end at a time with a little water and electrolyze the thing, then do the other end with reversed polarity.

I remember all the goop you would get using aluminum electrodes trying to make hydrogen and oxygen by electrolysis.