Portable pre-amp with digital??

enthalpystudios

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Anyone ever design or see a design for a portable, opamp based, mic-pre that can convert to digital to go into an MD player's optical in?

I was thinking it would be great to skip all of the MD's mechanical noise and crap electronics and maybe get some nice portable recordings of stuff (ya know.... recording silence and what not)

If one can make a green pre mobile, cool... i just have no clue about the digital.... could 9v(s) power a green pre and a single channel 16/44.1 converter?

Just thoughts, wondering if anyone has done anything similar.

Billy
 

clintrubber

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I expect that just making an external mic-pre and going to the MD's (analog) line inputs will give you 90% of the improvement at 40% of the total hassle.

There's Kevs dual mic-pre, battery powered - I've looked but can't find a link right now. uses 2019 (?), LM833 & SSM2142.

Bye,

Peter
 

mcs

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You could also use the That mic pre circuit discussed elsewhere here - you can't get a mic pre that's much smaller...

Best regards,

Mikkel C. Simonsen
 

clintrubber

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Runs on either batteries or mains:
ubb1002_medium.jpg




sorry
 

12afael

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there is a TI chip that have adc/dac stereo , usb , and spdif.
If I`m right is posible to convert the spdif to optical out with a MAX-xxx chip.

I will try to build some like that. but at this moment I have the usb conector, the usb chip , the cristal and a bunch of ina217, ssm2019 , ina163. for the mic input. and a lot of projects on the bench.
 

clintrubber

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[quote author="12afael"]there is a TI chip that have adc/dac stereo , usb , and spdif. [/quote]
At first I thought I owe it to my employer to mention the types that could do that job as well but then I realized you'll very likely end up with something alike to what's already in that MD-recorder.
So what's the use of doing it once again but now externally with a handy has-a-lot-onboard IC ? Unless you go for converters that could make a difference, but then your parts count etc will increase.

So ignore this ! :wink:

So again, I don't know your quality & convenience requirements, but using the analog line-inputs will do fine I expect.
 

babyhead

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http://www.thatcorp.com/1510desc.html

Or you could power some Neves off of 2 car batteries!!

Merry Xmas!! :green:
 

PRR

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> using the analog line-inputs will do fine I expect.

And interestingly, the max input on 3V stuff like that (if the Philips datasheet is typical) is just 1V, and there may be 20+dB of gain available, minumum input ~70mV.

This is a whole different range of gain and power than we need for "studio" gear. The maximum usable gain is only about 20dB-30dB, and no need to get over a volt of output. The minimum gain needed for loud sources is close to zero dB.

Getting gain down for hot sources may be challenging. Getting +48V Phantom power may also be annoying in a mini-Disk size package.
 

paddy

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[quote author="enthalpystudios"]Anyone ever design or see a design for a portable, opamp based, mic-pre that can convert to digital to go into an MD player's optical in?[/quote]

Hi, I have looked into making one of these before but had difficulty getting hold of the crystal spdif chip and also the toslink optical connectors. I decided it wasn't economically viable in the end.

A couple of solutions that were available then included the Mindprint DI-PORT and the Roland MMP-2. There are probably more available now.

Since the minidisk is compressing to atrac format anyway I think a lot of the advantage of the spdif input is lost, you should get satisfactory results with a balanced preamp driving the line in.
 

enthalpystudios

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Very cool comments everyone...... got this thing 'regifted' as a white elephant gift at a christmas party actually. Probably was the only thing anybody thought I'd like, as most people I know seem to have no earthly idea about what I'd like as a gift.

I may check into that UA5..... I'm not actually used to using any digital i/o aside from ADAT and TDIF, so I'm not sure about the specifics of getting into that 1/8" optical input on the MD. Basically I was thinking.. "hmm this has a digital input... If I used a good preamp and a good AD, I could probably make some pretty decent location recordings with this." Just figured it wouldn't be too tough to at least beat out the MD's electronics... noise floor on this thing is pretty crappy.

Mostly thinking out loud in about the best place to do it. Going to have to test my newbie noggin out on this one....

thanks for the replies


billy
 

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