My Latest Build

[LyleCaldwell]

This one has two standard loop selectors for the TC DPEQ (almost always on) and A3 on front (not used enough for the client to use up a GCX loop on), and then two switches that select what channels go to a DL4 for looping purposes.  Inside it contains two mono 4x1 mixers that can be routed as one stereo mixer, two mono mixers in series, or two mono mixers in parallel.  The mixer circuit as a whole can be used in a series or parallel configuration.  The mixers are at unity when the two knobs on front are at noon, but will give 2:1 when the knobs are all the way up and will attenuate in the other direction.  There is a ground lift for a parallel shimmer path, and a switch on the back selects between front outputs and rear outputs, so it will work with a racked power amp or going to the returns of a standalone amp.

It's a fairly standard non-inverting opamp based circuit, using Analog Devices AD826s (though the comparable Burr Brown would also work), with a rail to rail voltage of 30 VDC, which gives lots of headroom. Very neutral sounding with no noise added at unity. There are coupling caps at the ICs to prevent oscillation, and it has a voltage doubling 9 VAC to +/-15 VDC power circuit based on the publicly published Rane shematic. Star grounded, and unused inputs are grounded out.

And it has blue LEDs, which seems to be of greater interest to most than all the tech stuff above.

Front:



Rear:



Some guts shots:

[AzzR]

Still not exactly sure what it does but if it runs as good as it looks then its gotta be awesome

[donald stringer]

Thats a real work of art. nice job

[tennisdude]

very professional 

[Connoisseur of Distortion]

the precision of its assembly is almost clinical... very neatly done!

[MartyMart]

Fantastic work, well done
Looks like the PCB  has space for some "additions" !!

MM.

[Mark Hammer]

That's my phone jack budget for the year!!

It may not look as sexy as some things posted here, but the switching scheme, and combinatorial possibilities are positively delicious.  I don't think many people realize hoiw much a good splitter/mixer, serial/parallelyzer circuit can do for your sonic palette.

Congratulations on moving to the next level. 

[gez]

Rear shots always do it for me... 

[LyleCaldwell]

Fantastic work, well done
Looks like the PCB  has space for some "additions" !!

MM.

I designed that PCB for myself, to give me 6 4x1 mono mixers, or as I use them, three separate 8x2 stereo mixers, two in parallel with each other and the third in series.  This client didn't need or want to spend the money to populate all that, so I just populated it with 2 mono 4x1 mixers.  I'm about to order newer versions of this design, but in smaller PCBs - one for the power section and then modular sections that hold 2 4x1 circuits each.  So I can choose how many modular PCBs to put together in each future mixer.  The spacing of components is also a little different in the new PCB layout - some of the caps were tight squeezes as you can tell.

Thanks for all the kind words!