Ribbon Mics and Preamp Impedance

[Somnium7]

I didn't see mention of a flux capacitor there. You really might want to rethink that design.

You knucklehead! Do you take me for a complete fool (as apposed to a partial fool)? Of course there's a flux capacitor, it should go without saying! How insulting!!!!

if impedance adjustments have the same effect on ribbons that they do on condensers, then yes, it can make quite a difference in the tone

I guess I'm gonna have to wait for my ribbon to arive to test this for myself. At this point in the design the effects of variable impedance will need to have a profound and unquestionably useful impact to justify the rather expensive switch I'll need to implement the feature.

 

[mshilarious]

if impedance adjustments have the same effect on ribbons that they do on condensers, then yes, it can make quite a difference in the tone

Variable impedance has much more effect on a ribbon than a condenser, at least a transformerless condenser. In fact, all the condensers I have measured merely suffer a reduction in output as input impedance drops, and max SPL handling is typically reduced. But there is no change in frequency response.

Obviously when you introduce a transformer into the equation, the load has considerably more tonal effect.

 

[Somnium7]

Earlier in this thread I posted a link to a document by Bill Whitlock of Jensen Transformers about his "bootstrapping" input circuit. I just found out THAT Corp. has licensed the design and incorporated it into their 1200 series IC. Here's the datasheet for it:

http://www.thatcorp.com/datashts/1200data.pdf

They are calling it "InGenius™". It's not a terribly expensive device. I found a place selling it for $6.25 in singles.

The really nice part of THAT's datasheet is it gives you all the mystery values from Bill's original schematics and the math to calculate them yourself (if you're good at math).

Tomorrow I'm gonna try banging this InGenius™ thing into my design just for shits and giggles.

 

[Ironklad Audio]

Variable impedance has much more effect on a ribbon than a condenser, at least a transformerless condenser. In fact, all the condensers I have measured merely suffer a reduction in output as input impedance drops, and max SPL handling is typically reduced. But there is no change in frequency response.

Obviously when you introduce a transformer into the equation, the load has considerably more tonal effect.

i ran both my rode nt-2a and a-t 4033 into an mpa gold a couple weeks ago and varied the impedance on both...and while there was definitely an abrupt difference in output, it also seemed as though there were slight tonal differences as a result of the impedance changes

it may also be possible that the differences were perceived due to varying loudness, but it seemed like there was a definite "sweet spot" for each

 

[mshilarious]

i ran both my rode nt-2a and a-t 4033 into an mpa gold a couple weeks ago and varied the impedance on both...and while there was definitely an abrupt difference in output, it also seemed as though there were slight tonal differences as a result of the impedance changes

Sure, there could be slight differences. But the difference with a ribbon mic tends to be night and day.