Quote:
Originally Posted by AdamOfBremen
...One question I have right now is about matching to the microphone input. I see this is 200 ohm. The microphone I am most interested in getting is a Ribbon Mic rated at 260 ohm. Is his a good match or is the mic too high? I read it needs to be the same or lower, though by how much I am unsure. There are other mics available at 150 ohm but these are not ribbon mics. A standard SM58 is 300 ohm (to give an idea of relative ohms).
I was hoping to go direct into the mic input yet I also have a mixing desk which I could use as a front end and send that into the line input. That has 2,500 ohm inputs. It's just that, I was hoping to use the Tandberg as a pre-amp because the mic is relatively low output...
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Ribbon mics, but especially older ones tend to have low output and so preamp choice can be crucial. Preamp noise which is not a problem with other mics can be so with a ribbon as source. Modern ribbons thankfully tend to have more output due I think to more powerful magnets.
These days there is usually no direct "matching" of the mic's impedance to the preamp's input impedance. Normally the actual input impedance of the preamp needs to be at least ten times that of the microphone or source.
You will usually be limited by the noise in the "mic and first preamp" combination. A second preamp normally just adds more gain but cant improve on the signal to noise ratio it receives.
If you want top performance from your ribbon mic you might be better off feeding it into a dedicated low noise preamp.
Ribbon mics can work very nicely but are fragile. The ribbon is easily damaged. It's even inadvisable to store the mic with the ribbon lying horizontally as over time the ribbon stretches and sags, degrading the output. Magnetic filings finding their way into the transducer element can also play havoc. Historically, ribbon mics were used as a higher fi mic than dynamics and before good affordable condenser mics came on the scene. The ribbon's natural figure 8 pattern can sometimes be an advantage but the most commonly useful recording mic has some sort of cardioid pattern.