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#1 |
Regular Crew
Join Date: Apr 2005
Location: Stockholm, Sweden
Posts: 65
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Thoughts on external FX1 microphone
Perhaps you are already bored with FX1 mic discussions, but here's one more.... ;-)
The Audio Technica AT 897 seems to be what I need for some of the types of shots I do. And it seems many of you guys think it's worth it's price, so I'll try it out. I want to carry as little extra equipment as possible, so I was thinking of skipping the pre-amp (=no Beachtek or similar). The FX1 has a low impedance unbalanced mic input. Since the input is low impedance no impedance transformer is needed for the mic, so it ought to work pretty fine just using a standard XLR to 3,5 mm jack, as long as the cord is short to minimize noise and such. The mic can be powered with a battery, no prob. Anyone tried that and compared it with using a pre-amp? Next step would be to fix phantom power to the mic, since the specs show that the dynamic range will improve for the mic. The FX1 provides 2.5 V DC out of its mic input, so we just need a DC-DC converter to step up the 2,5 V to 24 V to use as phantom power. I was thinking about building it really small, all from surface mounted parts, (for instance around a SO8 mounted MAX630), perhaps small enough to fit inside a XLR jack. And then mount a pair of these XLRs more or less permanently on the FX1. Any comments? Will DC ripple from the DC-DC converter ruin the sound? It's just parts for maybe $30, so it's a pretty cheap try. I've looked on the web for this kind of adapter but not found one. I think it would be ideal for FX1 or camcorders with similar problems. EDIT: The output impedance of the 2,5 V mic jack is 6.8 kohms, so it will probably not be enough current for the phantom power. But it could be worth a try. |
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#2 |
Major Player
Join Date: Mar 2005
Location: Prague, Czech Republic
Posts: 500
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You need 48 V if you record drums at very close distance or something, I think. For camera mounted mic or fishpole mount, etc., internal battery is fine. Just use transformer, nothing else.
Radek |
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#3 |
Regular Crew
Join Date: Apr 2005
Location: Stockholm, Sweden
Posts: 65
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Thanks for the reply Radek.
Why would I need a transformer for the mic? It seems to be no impedance mismatch. The mic has 200-300 ohms, and the FX1 spec says "low impedance", which probably is about the same. http://www.audio-technica.com/cms/wi...4dc/index.html Have you tried this setting, just using a XLR - 3,5 mm jack with built in transformer with success? |
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#4 |
Trustee
Join Date: Dec 2002
Location: Gwaelod-y-garth, Cardiff, CYMRU/WALES
Posts: 1,215
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Bjorn,
My AT897 goes straight into my FX1 - and the sound is superb - no problems. I have the choice of going via the Beacktek box as well, but it's not really necessary... Robin |
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#5 |
Regular Crew
Join Date: Apr 2005
Location: Stockholm, Sweden
Posts: 65
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Thanks for the info Robin. I will try it out.
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