6U 8 channel Neve mixer

[tskguy]

Amazing!! I was wondering if you had any inside shots??

 

[baadc0de]

Not many,

but here they are, from development

First channel on test. The main (green) PCB is from bruno2000, the small white PCB above it is a local regulator for the channel, phantom power supply and mic input Z relay. The brown PCB on the far right is the PSU for the whole system.


AMI Neve transformers (mic inputs and line outputs, line inputs I scored some original Marinair)


Rear shot of the motherboard with the mixing & summing PCBs. If you squint a bit, you can also see where the D-Subs for mic inputs, line inputs and line outputs go.


Front view of the (back then) unpopulated motherboard with first channel slid all the way through. Connectors are DIN for Eurocards / VME systems, as is the chassis etc. Eventually there have been more guide rails installed to support the weight of the mixer.


Hope this helps!

 

[Toure14]

Will you be selling any pcbs, face plates, metal work, and b.o.m? ;D

 

[baadc0de]

Will you be selling any pcbs, face plates, metal work, and b.o.m? ;D

The PCBs are available from bruno2000. Face plates and L-bracket metal work from diy-racked.com, he has my permission to sell and I think has some reserve plates too that I never got about to needing. Switches are from brett at blore edwards, transformers from oliver at tab funkenwerk... kind of hard for me to sell anything not much of it is that original or hard to get. Knobs for instance can now be obtained easily with Jeff from classicapi. Inductors (and transformers, if you swing that way) from colin at audiomaintenance. The mixing stuff is really specific and there's software with it, a bunch of stuff isn't really mine but is a collaboration, so I recommend you roll your own for the time being, but I guess most of you guys would prefer the tracking side anyway it's kinda expensive to add channels to this, but I'd sure love to add a few more! Next stop is a batch of 1081, but don't count on it this year..

 

[AudioHammer]

Could you draw a block diagram or schematic of the gain control and automation?

Very cool build!

Audiohammer

...


The unblanced out from each channel is taken to a stereo MDAC (an AD5545 /AD4004 combination) where they are multiplied in such a way that the analog signal is the reference voltage and the DAC signal is the set gain constant with 16-bit precision. In this case, the DAC generates just a precise voltage to do (analog) multiplication with.

After this stage, the results are summed in a Neve passive bus kind of way, taken to another stereo MDAC, where master level is controlled and then leaves to the BA283 stages via 31267 transformers. So all signal manipulation and summing is actually analog, just the control bit is digital

Speaking of which, the MDACs are controlled with a Beaglebone (revision 6 I believe) which is a ~700Mhz ARM machine running Linux Angstrom. I have written some software (in Java 7.0! hehe) that is an mDNS responder, an OSC server and RTP node. By using DHCP and mDNS, the machine is put on your LAN and voila, in at most a minute, service discovery is done and it's ready to receive fader and pan set events via OSC or RTP.

 

[baadc0de]

 

[AudioHammer]

Thanks for the block diagram. 

Is the AD4004 that you mention ADA4004?  I can not find AD4004 on the Analog devices website. Do you hear zipper noise on gain or attenuation changes with the MDAC?

 

[baadc0de]

Thanks for the block diagram. 

Is the AD4004 that you mention ADA4004?  I can not find AD4004 on the Analog devices website. Do you hear zipper noise on gain or attenuation changes with the MDAC?

Sorry, AD5545 and ADA4004. There is some zipper noise and we're working on redoing this with optofets and some other ideas we're kicking around to control digital noise. I would sure love to see what SSL did in their Sigma MDAC summing mixer.

 

[r.paige.eo]

Amazing build, and gorgeous too! 

 

[djn111]

Hi,

First of all awesome build.

Would you mind sharing the order/part number for the switches ?

Kind regards

 

[Slenderchap]

This may help with switches:
http://www.audiomaintenance.com/acatalog/Concentric_Switches.html

Colin
www.audiomaintenance.com

 

[djn111]

Thanx Colin,

as always.

DJN

 

[Bomper]

Just to check. Are you controlling your faders (aka DAC's or vice versa  ) from within your DAW? If you are, how does this work? Is there some standard protocol to use?

Insane build by the way!

 

[baadc0de]

Just to check. Are you controlling your faders (aka DAC's or vice versa  ) from within your DAW? If you are, how does this work? Is there some standard protocol to use?

Insane build by the way!

There is a small oiece of software written on the host computer that translates HUI that get transported to it by midiox or something similar from the daw software. When the fader changes, a hui surface would also need to move the physical fader. We just move the dac fader instead The messages are translated to OSC, following a slightly modified standard that behringer uses for its own digital desks. This protocol was used because you can use touchosc and some daws are already supporting it quasi-natively (reaper and ableton...)

 

[jplebre]

Sorry to hijack the thread, but if anyone is considering taking the plunge and building this I have 8 PCB's for this project.
It's from a more recent revision than the one used on this project but identical.

My financial and time commitments changed incredibly so I don't see myself starting this for the next 5 to 10 years so I think it's best I give it a better home than my socks drawer

 

[sharpeleven]

Sorry to hijack the thread, but if anyone is considering taking the plunge and building this I have 8 PCB's for this project.
It's from a more recent revision than the one used on this project but identical.

My financial and time commitments changed incredibly so I don't see myself starting this for the next 5 to 10 years so I think it's best I give it a better home than my socks drawer

PM'd

 

[jplebre]

Sorry for the delay I've been away.
I've seen the email notifications and I believe my inbox may be full will try and reply all today

Cheers
J

 

[mtrack]

Very Nice.  How do the AMI output transformers sound compared to original LO1166?

 

[r2d2]

Eventually got a better pic

push buttons wìth light are custom or industry ?

 

[Whoops]

Looks amazing, great work