I got an age-old Sony F-99B dynamic microphone lying around while I was looking for gear to shoot an interview-style podcast. Now, I understand that dynamic mics output mic level signals that should be pre-amplified before they can be reliably used. Connecting this mic to an ordinary sound card on a PC gave me very very feeble sounds.

The question is what do I have to buy to record audio using this. Do one of those cheap USB audio interfaces work? I mean do they provide sufficient gain? If not, what should I be using? What specifications should I be looking for? There's nothing written on the mic except that its "low impedence"

Also, I'm on a budget.

1 Answer 1


This & your other question really get the same answer.

You key point is that the mic is Low Impedance.
Most pro mics are.

Consumer mics, however, those typically used for headsets &/or Skype etc are High Impedance.. & that's where the issue lies.
A low impedance mic in a high impedance socket will sound like pants ;)

That's why you need an impedance-matching transformer. However, by the time you've shelled out the 25 or so bucks for one of those, you may as well pay the extra 10 or so & get a proper external USB 'soundcard' system designed a) for low impedance mics & b) which will have a far better mic preamp than your computer.
Even the very cheapest - maybe 35 $£€ or so for a decent entry level one, will totally out-perform the one in the computer.

Check out which you'd like - not on eBay or Amazon, but on a 'music shop' site. They will already be selling only the type that will be useful to you, less likely to be mixed in with high impedance consumer stuff. [You can buy it where the heck you like once you've figured out which you need, but a music shop will set you off in the right direction]. I'd probably suggest to get one with phantom power as it's pretty much a free add-on & might come in useful if you ever use a condenser mic.

Thomann are a large EU music 'box shifter' so they're a reasonable place to start. I can't recommend anything specifically right down at the low end of prices, I've never used anything below about the 150 mark, by which time they're pretty decent all-round. I see they've got an entry-level 'cable that does it all' type thing for €13… no idea whether it's any good, but it's certainly cheap ;)

Late Edit
I only just looked up that specific mic - yes, I now know I should have looked it up first ;)
That's a bit of an oddball, as it's a stereo mic, terminated in twin 3.5mm mono jacks. Some odd 80s home hi-fi thing that is a mis-match to most modern gear.
That means you going to need a stereo-capable pre-amp & also some plug converters to get it into that. Because it's unbalanced & a mic pre will be expecting balanced, you might also need one that can share the input between mic/line/instrument, which might better cope with it being an unbalanced source.
Info source - http://www.gbaudio.co.uk/data/f99b.htm

By the time you've bought all the bits necessary to get that to interface with your computer, then unless you actually need stereo, I'd save your time & money & buy something like a Blue Yeti instead. Simple half decent consumer-level mic to USB, all in one.

  • First of all, thanks! So, I don't really care about stereo. Can't I plugin the left and right separately to the two channels of a mixer and take its output?
    – sixter
    Commented May 31, 2020 at 13:46
  • So long as you impedance-match sure.
    – Tetsujin
    Commented May 31, 2020 at 14:54

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