Shure SM 57 Battery Mic Preamplifier
- Thread starter Liutmod
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Bo Deadly
Well-known member
For a simple battery powered mic pre there are quite a few options.
The simplest would probably be to just use an op amp. Or maybe two - one for gain and one for the line driver and another 20dB of gain. Like an API pre but run on +-9V.
Another option would be to use an older discrete single supply circuit. There is a fairly standard circuit for that found in a lot of older gear like Neve consoles and Studer tape machines. It uses 2-3 transistors. Here's a stripped down version of one from a ReVox reel-to-reel recovery amplifier that only uses 2 transistors:
But this is designed for 24V so things would have to be adjusted a little to get it to run on one 9V battery. And you still need a line driver circuit which is at least another transistor. This circuit has the potential to use very low power (last for days on one 9V battery) and to be very quiet because the circuit can be matched to the mic.
The simplest would probably be to just use an op amp. Or maybe two - one for gain and one for the line driver and another 20dB of gain. Like an API pre but run on +-9V.
Another option would be to use an older discrete single supply circuit. There is a fairly standard circuit for that found in a lot of older gear like Neve consoles and Studer tape machines. It uses 2-3 transistors. Here's a stripped down version of one from a ReVox reel-to-reel recovery amplifier that only uses 2 transistors:
But this is designed for 24V so things would have to be adjusted a little to get it to run on one 9V battery. And you still need a line driver circuit which is at least another transistor. This circuit has the potential to use very low power (last for days on one 9V battery) and to be very quiet because the circuit can be matched to the mic.
Bo Deadly
Well-known member
Not really. Most mic pres run on +-15V or +24V and have phantom. So your requirements are a little unusual. It's very possible to make a perfectly functional mic pre with no phantom power that runs on 9V. It's just not something I've seen before. If you use two 9V batteries to make +-9V, there probably are lots of options but I still don't have a final circuit in mind. It sounds like what you really want is a PCB ready to go. So just google "mic preamp PCB". Of course there's a lot of nonsense on the web so you might try also narrowing the search down to an IC that is specifically for a mic pre. For example, google "ina217 pcb" or "that 1510 pcb" ("that" is actually the name of a company that makes audio related ICs).Liutmod said:
Pip
Well-known member
Think 5532 chip. Do a search for schematics. See below.
https://www.banggood.com/DC-9-24V-AC-8-16V-NE5532-Audio-OP-AMP-Microphone-Preamps-Pre-Amplifier-Board-p-1119466.html?akmClientCountry=America&cur_warehouse=CN
https://www.banggood.com/DC-9-24V-AC-8-16V-NE5532-Audio-OP-AMP-Microphone-Preamps-Pre-Amplifier-Board-p-1119466.html?akmClientCountry=America&cur_warehouse=CN
> I am searching for a battery preamplifier schematic optimized for Shure SM57 (or other dynamic microphones) I need this preamp for "on the fly" recording
There is SO much you are not telling us. You will continue to get random suggestions until you tell better.
What are you going into? A radio network? Presto disk-lathe or a mike input on a pocket recorder, or a line input, or? ? ?
How much gain do you really need? If you are going to a mike input, you don't need much gain at all.
How close is the SM57 to this preamp, and how adverse is the environment? If the SM57 is within a few feet of the preamp you do not need balance input; if hundreds of feet of cable anywhere around utility power, you need careful balancing.
This has been built several times, it works, is clean up to reasonable limits. It was "noise free" in a large practice room with lots of fluorescent lights, usually some blower rumble, and 50 foot unbalanced medium-Z mike lines.
There is SO much you are not telling us. You will continue to get random suggestions until you tell better.
What are you going into? A radio network? Presto disk-lathe or a mike input on a pocket recorder, or a line input, or? ? ?
How much gain do you really need? If you are going to a mike input, you don't need much gain at all.
How close is the SM57 to this preamp, and how adverse is the environment? If the SM57 is within a few feet of the preamp you do not need balance input; if hundreds of feet of cable anywhere around utility power, you need careful balancing.
This has been built several times, it works, is clean up to reasonable limits. It was "noise free" in a large practice room with lots of fluorescent lights, usually some blower rumble, and 50 foot unbalanced medium-Z mike lines.
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radardoug
Well-known member
Why dont you use the mike preamp in the recorder? What kind of recorder?
RuudNL
Well-known member
Liutmod said:
It depends on the input sensitivity of the line input.
(That can be anything between 40 mV and 1 V.)
okgb
Well-known member
This almost seems like a troll, Do allot , of research and see if there is something common to what people are saying and you'll probably learn something in the process. If you're willing to accept simple circuits, then try a few and find out what works for you.
If you're trying to be cheap it maybe frustrating if you're in a hurry. No free lunches but you can always find a deal [ if you look long enough ] then come back and share your findings!
If you're trying to be cheap it maybe frustrating if you're in a hurry. No free lunches but you can always find a deal [ if you look long enough ] then come back and share your findings!
