|Bozure M1 - Mixer.
The M1 mixer is very "inspired" by the original UREI 1620 mixer and have almost exactly the same core functionality and is designed in a similar way.
The focus off this mixer is to be as easy and cheap to build as possible without loosing functionality or quality.
The main design goals for the M1 mixer is:
- Easy to build.
- Cheap to build, a minimal number of components is used. It only have 7 IC's.
- Be used in almost any enclosure, 19", desktop etc.
- Can be used as a 2 Ch - 6 Ch mixer.
- FX Loop.
- Cue - Master Headphone Blend.
- Tape out.
- VU Out.
- Booth Out (unbalanced).
- Master Out (balanced).
- OP: TL074/TL072, NE5532.
- Caps: ELNA Silmic II, WIMA.
- Resistors: Carbon Film.
- Pots: ALPS RK27
Internal wiring: Mogami (Used in my build)
There is also a lot of blog posts about this build in the blog section:
The M1 mixer use 3 different PCBs, 2 Audio PCBs (B101,B102) and one PSU PCB (PSU1 - B103).
Here it is with just the 2 Audio PCBs installed.
The reason for the veroboards is so that it can be used in any enclosure 19", desktop etc. And use any brand and models of pots and switches.
More info about this is available in the blog section.
Here is the functionality:
Main Mixer Audio (B101) + volum pots and components around them.:
(The mixer can be used with 2-6 input channels, above is a 4 ch example)
CUE/Master blend, headphone amp (B102) + volume pot:
A complete mixer using just 7 IC's, how is that possible ?
The core mixer PCB don't have Phono amps and EQ (this can be added if you want), also the Booth and Master outputs is either unbalanced or balanced, not both. All this combined with an optimized design saves a lot of components. It also use Quad OP-Amps, just like the original UREI 1620 (TL074) .
The Master/Both outputs is designed to save components and make it easier to build. The Master output only have a balanced output but you can connect it to an unbalanced amp input if you want. To do this you use a simple XLR to RCA adapter.
And the M1 mixer can use all of the extra functionlity cards described for the M4 project, these are not M4 specific. So you can add almost any extra functionality that you want.
There is a VU Out, what is this used for ?
This is so that you can monitor the level of the signal that you are Cueing, or the master signal if you select that. If you are using a desktop enclosure you can add a VU driver card and have some VU meters connected to it. If you use a 19" enclosure you connect it directly to Bozure EQ1 (Next project) or something like this: