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building your own mic preamp and a/d converter

I just bought a creative nomad jukebox3 from ebay:

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Bought it to do some field recording, sounds, concerts.

Ideally I'd like something like this:

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I can't afford it though.

I was wondering if there are any do it yourself plans I can use to make my own mic preamp and a/d converter. I would like to have professional quality and it has to be portable. What parts are recommended? How difficult is this to build and how much would it cost?

I'd also like to have a meter for understanding the levels going out of/into a device so I can correctly set the input levels on the next stage, in my case, the NJB3 [which has input metering]. Any do it yourself plans for this?

Btw, I also own earthworks m30bx battery operated microphone:

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which I intend to use for the recordings; I was wondering if anyone knows how to convert it into a directional boom mic? Any advice on how to do this?

Thanks, Marc

Reply to
marc
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Tom's Hardware has a thorough review of the nomad 3 with detailed specs:

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Here's a link I found on a diy portable mic preamp:

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marc

Reply to
marc

Bitof a ramble ahead.....

Making a reasonable micamp isnt too difficult, INA217 from TI for example. Dont bother with NE5534/2's these days for mic amps, ok for the rest Its all the other bitz that go around it, like monitoring, LF cuts etc I think the 302 is nice, I havent played with one, but they seem to squeeze a lot of functions out of 3AA cells. but condoms come in packs of 3, not AA cells, what do you do with the spare one?

Getting the power side organised and efficient could be a problem.

First of all, what are your minimum requirements, there is a lot of stuff on the 302 that you wont need (T powered microphones???) and an MS matrix, unless you are using a mkh816? mic If you are using 24bit, you could get away without limiters, if you are careful. You wont need +22dB out into 600 ohm, thats boring specmanship these days. You may want to beef up a good heaphone driver, I'm just pissed off with the one I've got on my XL1s Nomad leave so much out of the spec sheet, its difficult to work out what the nomad could do, that you could leave out of the mixer without playing with the toy first.

So start of with a basic stereo ina217 with gain switches, followed with an LF cut, followed by a good dual gang stereo pot. Then for the monitoring, have an A/B switch with gain makeup so you can matchthe levels from the micamp to that of the nomad. Led drivers.. LM3915/6 use the PPM circuit (in dot mode to save power) fom the app note.

And for the power supply, ask Genome......

martin

Opinions are like assholes -- everyone has one

Reply to
martin griffith

doesn't the nomad have built in a/ds?

there are lots of mic mixers w/ preamps to be had.

Mark

Reply to
Mark

I read in sci.electronics.design that martin griffith wrote (in ) about 'building your own mic preamp and a/d converter', on Sun, 20 Mar 2005:

I would recommend a linear power supply, not a switcher. This is a low- power application, and, while it's possible to keep switcher noise out of a mixer, it isn't easy.

If it's not functionally inconvenient, an AC output wall-wart is the way to go. Using on-board half-wave rectification, you can easily get + and

- rails, while retaining a simple 2-wire connection from the wart.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
There are two sides to every question, except 
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Reply to
John Woodgate

Yes it has a decent a/d converter. But you can always get better ones. It records up to 16bit/48kHz. In WAV format, you have a choice of sampling frequency: 48kHz, 44.1kHz or 32kHz in 16 bits. With a quality mic preamp you can get some excellent recording in

16bit/48kHz. And the recorder only goes for $150 on ebay. It's an inexpensive solution for quality portable field recording.
Reply to
marc

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