Help me to create my Portable Audio mixer

Hi,

I'd like to build a Portable Audio mixer like this one :



I know that It will be difficult to Build a audio mixer as good as a SQN but in fact I'd like to have these caracteristics :

- 2 Good and transparent preamps ( maybe Green preamp?)
- 48 V Phantom
- 2 pots or 4 (Gain + volume ) for the trimmers.
- a Headphone OUT so with a pot to control the volume.
- 2 VU-Meter or led meter.
- Phase, High pass, Pad for each input.
- Need to use a battery for power supply.
- A Stereo Mode.

I know that my project is not easy to build but If you can Help me on some points... I will be glad

thanks :grin:

Sounds to me like..
Kevs battery powered Green stuff
CMoy Headphone amp
Passive mixer
Relay boards - currently being offered

This would be very cool.

Looks like you could make this by combining different projects featured here.

I think something like The Green or SSL9K would probably be a nice choice for preamps from what I've heard.

You've gotta get the power supplies worked out first. In the case of a small battery-powered mixer, that's the hard part!

You can get NiMh rechargeable AA batteries cheap with a capacity of around 3000mAh which is pretty massive. I'm not sure about the capacity of C or D cells. I bet they are big.

Are you going to put a limiter in there aswell ? Im a big fan of the Sqn limiter I think they have a description of of its ballistics on their website I think its fet based but dont quote me on that.

Thanks guys.

YEs the hard part will be the Power supply, I will have to use preamp circuit which works with 12 volt or 18 volt...

I think that Green preamp or JLM baby animal preamp are good value.

I gonna works on a synoptic to have a better way to start.

Yes Nimh battery are a good cheap solution. it will give, I guess enough ampere for the circuit.

dolo72, I'd like to put a limiter but I did'nt find good and small Limiter shematics.

And what about your phantom power? It's easy if you only need +12V T-power, a bit more complicated if you want +48V.

With battery power, you must pay very careful attention to the current draw of all the circuits involved. A portable mixer is worse than useless if it dies or flakes-out on you in the middle of a job. That's why people pay the big bucks for something like a Sound Devices, SQN, etc. They do the job reliably.

The PSU is possibly the biggest pain in the ass involved in the whole project, so best to get the basics of it out of the way before worrying about which "flavors" of preamp to use.

Find out the current draw for different preamps. You'll want long life. I run a preamp from alkaline 9V batteries and it doesn't last long....

Maybe someone can suggest a simple limiter.

You could try using those DC/DC converters to get 48V. I don't know much about DC voltage multiplication though. See The Drawing Board just now.

yes 48 volt will hard to get with only some Battery...

YOu have right NewYorkDave, Firts , I will search on the web some Power supply schematics.

Five or six 9V batteries might work ok.

Some of the dc-dc converters from www.Tracopower.com get a +/- 15 supply from 9-18 volts input. Very small aswell with some features geared for battery supply. Im not sure how suitable for audio they are though (noise etc) I just remember looking at them when I was considering a similar project.

Also I do have a partial schematic and pcb plot for a small fet limiter i can email to you (cant host). I photocopied it from an old copy of studio Sound. Unfortunatly it runs on +24 so it might overcomplicte things trying to get another voltage from your power source. Just pm me.

I have an EELA AUDIO Reporter mixer for sale.
Needs some work but it has (I believe )6 preamps with Studer or Haufe trafo's, ( Sifam)Vu metering, Peak Leds, Auxes, Headphone outs, and a compressor section on the stereo buss, but I'm not sure about this, could be only an insert as well.Hi pass filters.
Phantom power.Powersupply or Batteries.
Check with EELA Audio first , they still have some documentation and Schematics and let me know if you have interest.

I didn't know eela audio equipment...

Is this one ?

http://www.eela-audio.com/Downloads/Product%20info%20S50.pdf

I'm maybe interested but it depend the price.

This looks like the holely gravel, does it live up to its' hype?
mrc

yes , that's the one .`

[quote author="mrc"]This looks like the holely gravel, does it live up to its' hype?
[/quote]

I dunno.... What do you think? :razz:

oh dear roddy
BTW - mathflan you did check out the Kev Ross hint for the battery PSU with a dual mic pre?

http://www.celestial.com.au/~rosswood/diy/dualmicpre/dualmicpre.htm

Did you ever finished this project?

What happened?