I'm a total noob in DIY electronics and I can't find ANY info, maybe due to wrong terminology knowledge. If it's answered in forum PLEASE direct me.
I'm going to build in-line mic preamp that needs 15-0-15v up to 18-0-18v and my goal is to get it using phantom power 48v from my audio interface. I know that I could get it by using 4x PP3 batteries (getting 0 from middle and +/- from sides), but that wouldn't be in-line preamp and I would have to hassle with batteries.
Thanks in advance!
I'm going to build in-line mic preamp that needs 15-0-15v up to 18-0-18v and my goal is to get it using phantom power 48v from my audio interface. I know that I could get it by using 4x PP3 batteries (getting 0 from middle and +/- from sides), but that wouldn't be in-line preamp and I would have to hassle with batteries.
Thanks in advance!
Please, can you direct me to schematic how to do it? I have only little schematic reading skills and no real understanding what components do. I just read and solder. Well, more I do it, more some understanding and ideas appear.
Your 48Vdc phantom power will probably have audio ground at 0V
If you split this you end up with 0V& audio ground, +24Vdc, +48Vdc
That is not the same as -24Vdc, 0V, +24Vdc
You could split the 48Vdc ONLY if it is isolated from all other circuits/PSUs.
If you split this you end up with 0V& audio ground, +24Vdc, +48Vdc
That is not the same as -24Vdc, 0V, +24Vdc
You could split the 48Vdc ONLY if it is isolated from all other circuits/PSUs.
a mic preamp that needs a bi-polar supply from phantom power....possible but not easy.
is there a particular reason for the preamp choice?
most high quality mic pre-amps i've encountered are single ended supply, class A devices.
is there a particular reason for the preamp choice?
most high quality mic pre-amps i've encountered are single ended supply, class A devices.
I really want to make it because I liked how low noise level is and it's clean sound.
If you know pre-amp scheme with similar or better noise floor and distortion level than INA217, I'm all ears. A complexity of schematic doesn't bother as long it's right and I can go straight to soldering.
Dunno if I'm digging in right direction, but Isn't it similar to DC to AC converter before transformer?
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I would not advise starting in electronics by building a microphone preamp and a DC-DC converter. Better to start with a battery-powered audio amp. Learn to read and write schematics.
> most high quality mic pre-amps i've encountered are single ended supply, class A devices.
There's a good lot of Broadcast Network gear designed around single 24V, so that in case of power outage it could be run on a couple truck batteries and keep the broadcast network working, even if the local transmitter was dark.
There's another big bunch using "op-amp thinking" with +/-15V supplies. Jensen 990 is a classic but the idea was everywhere, and continues to this day.
This question of +48V +24V +15V and -15V (maybe others) keeps coming up on studio audio geek forums and is always frustrating.
There's a good lot of Broadcast Network gear designed around single 24V, so that in case of power outage it could be run on a couple truck batteries and keep the broadcast network working, even if the local transmitter was dark.
There's another big bunch using "op-amp thinking" with +/-15V supplies. Jensen 990 is a classic but the idea was everywhere, and continues to this day.
This question of +48V +24V +15V and -15V (maybe others) keeps coming up on studio audio geek forums and is always frustrating.
You can amuse yourself with this circuit with LT-Spice to adapt it depending on the current possebilities of the 48V supply and the need of your application.
Mona
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Ketje is correct if the zenerr and voltage divider are carefully chosen for the power draw on the +/- rails. Regulation won't be great for the neg. Rail but should be in the 10% range over a limited range.
I think if it were me I would add a 24V zener to the 24v rail. Just my thoughts so take them for what they cost you.
I think if it were me I would add a 24V zener to the 24v rail. Just my thoughts so take them for what they cost you.
Not necessarily.
And you don´t need or deserve the incredibly rough answer :
You have a problem?
Ok, let´s try to solve it.
First of all, you should post here the schematic of the working preamp you intend to build, only it needs +/-15V (which you don´t have) instead of +48V (which you do).
IF you do not have such a schematic, just a vague idea about "ina217 is the best mic preamp" then you have a long way ahead and I suggest you build some tried and tested circuit.
IF you do, please post it here for analysis.
The point here is that very probably you do not *actually* need split supplies (we are handling Audio here, not minuscule DC voltages which is the other use for it) so it quite possibly can be converted to 30V single supply operation, which if properly done is equivalent to+/-15V
If you do not have a working mic preamp schematic, I´ll suggest a single supply application for INA217 , no big deal.
Only problem is that it has a relatively high current consumption, some 10/12 mA ; will your Phantom supply be able to sourde that?
Even if available voltage is less than 30 V at that current, no BIG deal either, since you will handle relatively low level signals it might work with as low as 15V DC supply ... single supply of course.
Hi,
Three points :
1) Phantom power is hardly ever enough to run electronics
except basic stuff that might be in microphone capsules.
2) Any interface with phantom power is by default fully
microphone capable, otherwise it would not have it.
3) Given the above two, you have no idea what you are doing.
rgds, sreten.
Three points :
1) Phantom power is hardly ever enough to run electronics
except basic stuff that might be in microphone capsules.
2) Any interface with phantom power is by default fully
microphone capable, otherwise it would not have it.
3) Given the above two, you have no idea what you are doing.
rgds, sreten.
1. 48V 6800ohm gives max output power of 0.34W.
+/-12V * 12 mA=0.29W. So there is not too much margin, but possible. And INA... can work with lower voltage also.
2. "Capable" and "very low noise" are different things.
3. Given the above two, you have no idea what you are doing. Nezvers is newbe and at least asked.
+/-12V * 12 mA=0.29W. So there is not too much margin, but possible. And INA... can work with lower voltage also.
2. "Capable" and "very low noise" are different things.
3. Given the above two, you have no idea what you are doing. Nezvers is newbe and at least asked.
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