Here's my portable, 2 channel preamp. With VU meters, 48V phantom, 12-step gain, 72dB, Balanced XLR in/out.

All powered by a 9-12V battery. (yeah, you could power it with a 6VDC battery, but Phantom Power will only be around 40V, instead of 48V.)

True 48Volt phantom power  (okay, it's only 47.956 Volts... short by 0.044 volts)

The guts:

Full size XLR inputs and outputs, Switchcraft locking DC jack, Grayhill, Bourns, CNC engraved panel

And here's some early prototype testing  ;D ;D ;D


Dude put a PCM 4222 A/D converter in there and retire...you will be rich...er...

Really looks nice...
Since the development of the internet millions of people have died, the two may or may not be related.


you kill me... honestly.

every time i get a little closer to catching up with your product offering, you release something else.

well done... a mighty fine feat of engineering. I do wonder where you find the time though :)
Expat Audio Home: http://www.expataudio.com


A customer requested something Blue... here's my TS-2 Mic Preamp - True Blue Special. 

Perfect for the TaperS crowd:

- Powered by 9V-12VDC adapter or portable battery
- Dimensions of approx: 6.5" x 6.5" x 2"
- Switchcraft locking DC jack adapter at the back,
- full size XLR jacks, no need to mess with adapters or custom jacks
- VU meters for quick verification you have signal
- separate on/off switch for VU meters to conserve battery life
- independent 48V phantom power switches per channel
- 12 step gain switch
- Trim knob
- polarity switches
- all switches recessed and hard to accidentally toggle on/off
- all aluminum construction, not plastic, better shielding too
- front brackets to protect controls
- Using THAT and Burr-Brown chips

Took some quick photos before this baby gets shipped out.


looks very nice.

three small suggestions:

label the channels front and back.  this is minor but every little bit you can help the user will be appreciated, especially anything that aids quick setup.

add a small hook on the back for looping the wallwart/battery cord through, so that it is more difficult to accidentally pull it out.  there would be room for it right above the inlet.  there are adhesive or screw mount hooks that would work, or you could cnc a small U in the back panel.

change the trim knob to a different shape than the gain knob, possibly smaller.  it is a very nice knob, but being able to grab without looking is helpful.  and if you could make the trim knob a bit smaller, it would help with the front panel, which is necessarily crowded.

that said... well done, owel.



I like that idea of a CNC cutout U shaped on the rear panel. Great idea!

if you could make the trim knob a bit smaller

I'll look into it.

Thanks for the suggestions.


Great looking enclosure.
Are you having those made custom, or is it a stock unit?  I've been looking for something similar, but larger for a bass amp head I'm building.

take  care

Where did you get that box from?

It certainly looks like extruded aluminum, which is a much better material to paint or finish than diecast.

I'm not so sure for CNCing, or for using the sides for inputs & outputs.

Price I'm not so sure either.


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