API 'The Box'

[electrisizer]

hey ian,
thanks for answer

1. i never use post fader aux. dont see any sense as my dry signal is controlled by the fader and the AUX/wet signal by the AUX Pot. but i could live with both, but dont need a SW to select.

So,when using reverb for example, if you fade a track, only the dry level changes and the wet stays the same or do you operate the fader and aux pot together? What happens if you fade to zero you are left with just wet.?

hmmm ian how about designing a "poor mans API 1608" i imagine there would be ALOT of interest out there. some things already exist like summing section or bus section via jeffs classic api stuff.... THAT WOULD BE REALLY GREAT

cheers nico

Now there's an interesting idea. It might just happen but if it is semiconductor based it won't be designed by me. Watch this space 

Cheers

Ian

yes i use fader for dry level and aux pot for wet level. most of time i leave the wet level at same position if changing dry level. my wet level (reverb) has to be a fitting fixed space in the mix no matter if theres a hot or small dry signal. for sure if i mute the dry level signal i have the wet level still triggering

 

[ruffrecords]

yes i use fader for dry level and aux pot for wet level. most of time i leave the wet level at same position if changing dry level. my wet level (reverb) has to be a fitting fixed space in the mix no matter if theres a hot or small dry signal. for sure if i mute the dry level signal i have the wet level still triggering

Interesting. It seems like everyone has a different idea of their ideal 'Box' - hardly surprising. It seems to me the missing element is the mixing glue in the middle that could provide AUXes, mix buses, mutes etc etc. Everything else, pres, EQ, dynamics is already avaialbe in 500 series. So it should probably look similar to 500 series stuff but with a backplane specifically designed for mixing.

Cheers

Ian

 

[mylesgm]

What I would like to see and am considering building is the part of the mixer that is not replicated elsewhere namely routing/auxes/sub groups etc.  I've got mic amp, EQs, dynamics coming out of my ears and don't really need a desk with these.  So essentially a line input (could have options like transformer input or DOA debalancer or simply a THAT receiver) then 4 or so auxes say 2 mono 2 stereo all switchable pre/post and then panpot and 8 bus switching.  Then a master section with master aux outs, aux returns, master bus outs, main out with insert and monitor out.  Why the bus system?
Well I would like to be able to do 8 track recording so I feed my 16-24 mic preamps into the mixer using the buss outs to mix to 8 track tape, using the auxes for foldback and for effects.  Then after tracking I can mix using the same system straight off the tape.  Now I understand that 8 track is not necessarily everyone's cup of tea but 8-bus is still a very useful feature.  Everything else on a console is already available in outboard and most people have tons of that already.  If I could build a high quality 16-8-2 mixer with just line inputs in a smallish form factor (4ru?) I'd be pretty happy.

 

[JohnRoberts]

I actually looked into kit mixer/console building blocks back when I was in the kit business. My concept was a kind of Lego block console approach where modules could be stacked, literally plugged together vertically to flesh out a channel, then stacked/plugged together horizontally to make X channels.  In-line or split console could be supported by different modules.

I quickly reached the conclusion that the overhead and extra points of failure from the modular approach would make the kit mixer even more expensive than a commercial assembles unit and less desirable.

The modular approach would answer the "it just needs a this" feature to be perfect crowd.

With a standard for vertical and horizontal interface, people could even roll their own custom modules if desired.

Still impractical IMO, but that doesn't stop some who roll their own entire consoles from scratch, which IMO is even more impractical.

JR

 

[pucho812]

paul wolf did that very thing with the whole tonelux v-rack system.  interesting concept for sure. Build as you go.

 

[JohnRoberts]

Yup some very old consoles were modular with perhaps a preamp section, an eq section,  pan/fader/assignment.  Different EQ options were probably supported, and different number of channels supported.  Paul may be channeling his old API roots.

I guess the overhead issue comes from how much granularity is provided for different options. Not practical for a kit business, since the number of customers would be small, so obscure individual modules would sell in even smaller numbers.  :'(

JR

 

[TheJames]

Ummm....Have you guys seen this?

http://classicapi.com/catalog/index.php?cPath=137

Build as many left/right "buckets" as you want.  There's a double high bucket too.  All you need to design is the bus routing piece, the summing piece, and the fader/pan piece.

You have enough considerations with that...Balanced/unbalanced summing buses?  How many?  What about panning/pan law?  Buffering between stages?  Not all modules handle the unbalanced signals that the VPR spec allows for.

Working with unbalanced signals is much easier and cheaper "inside" the console.  Perhaps your fade/pan/aux/routing module has unbalancing and balancing in it as well as the stuff for selecting channel inputs, and bucket routing (Bucket 1 feeds bucket 2?  Bucket 2 feeds bucket 1?).  Or maybe you forgo the bucket routing and instead put a switchable insert point.  Maybe you do both?

This will get big fast.  A bucket for mic pres, a bucket for EQ, a bucket for compression, then a line of auxes, and another line of faders....You're going to end up with something that's a large format console.  Literally 3 feet deep and probably 3 feet wide for 16 channels by say 8 buses and 4 auxes with returns.  Look at the size and weight of an API 1608.  That's what you'd make.

Assuming $300 a module:

16 channels of preamps  $4800
16 channels of EQ          $4800
16 channels of comps      $4800
Metal/woodwork/backplanes cabling              $1500
Mixer pieces (faders/auxes/ summing etc)    $1000

Of course you can scale that whichever way you want....Drop the pres....Drop the comps...Drop all but the mixer pieces....It's still going to be pricey.

 

[mitsos]

Looking at the costs, might be better off buying an old console and modifying it. That way you get all the infrastructure done for you. A lot of old 70/80s mixers use inverting amps for summing, using TL072s. You can upgrade these with new ICs, or you can patch in a classicapi ACA-bo and have your self a killer master with all the rest working still.  Or since they'll all have some kind of resistor summing, you can probably patch in a 1272 and have yourself a neve summing bus. It's much easier than building the whole thing from scratch and the basics are all the same, just have to research the console you get.

If the input on the console is only so-so (like the TAC), you can make a little PCB very easily or modify the circuit on the original PCB. Both work.  For me, I got a TAC scorpion, and I'm going to make a little PCB like the AML ones but with mic/line capabilities, maybe trafo/2520, not sure yet.  You can even put LED VU meters on the preamps if you want. Might be cool to make some "generic" or even console specific PCBs if there were more people interested and could provide measurements. A premade SMD led VU would be very cool.

Anyway, if you can find yourself a small enough mixer it will be cheap, and you can put anything you want in it.  I'm even going to do simple little VCA compressors in the groups, to comp drums or room mics, or whatever.  Patches internally right at the insert point.  All it takes is some shielded cable to run the signal back and forth.  Total cost is much lower than above, not counting my labor of course, and also that the console was pretty much free.

I'm still be interested in a fully custom master section if one comes up here, but not so much in custom metal work.

 

[JohnRoberts]

ding ding ding...

The problem with such large scale DIY is you will never recover a fraction of the parts cost, let alone the labor.

There are lots of old soldiers being given away for pennies on the dollar as the new cheap digital desks alter the console food chain.

If using an old soldier as a platform. Start with something that doesn't suck.

JR

 

[ramshackles]

for those interested, I started a somewhat-related thread about getting multiple uses from a single board design:
http://groupdiy.com/index.php?topic=54418.0

The ultimate goal being trying to wrangle a little project mixer out of it...

 

[Biasrocks]

I can understand buses being post fader but I have never understood direct outs being post fader. If you use a fader to set the level you cannot use it for a monitor mix. Maybe a trim control for the direct out leaving the fader free for mixing?

The direct out being post fader allows you to run the pre-amp hot if you want to or adjust your level to tape.

An especially useful feature if you're running discrete pre's like API's or Neve's.

As far as level to mix, most recording consoles have a monitor section for use when your tracking through the rest of the console.

Mark

 

[ruffrecords]

I can understand buses being post fader but I have never understood direct outs being post fader. If you use a fader to set the level you cannot use it for a monitor mix. Maybe a trim control for the direct out leaving the fader free for mixing?

The direct out being post fader allows you to run the pre-amp hot if you want to or adjust your level to tape.

An especially useful feature if you're running discrete pre's like API's or Neve's.

As far as level to mix, most recording consoles have a monitor section for use when your tracking through the rest of the console.

Mark

I can understand the need to tweak the level through the pre to alter the sound ( especially with tubes ) and the fader allows the overall level to be kept in bounds before going to tape. However, I can just imaging some idiot accidentally moving a (slider) fader thereby ruining an important take so I have something of an aversion to  faders (of the sliding type) being in the signal path during a take - in my book they are for mixing and monitoring. I would rather there be a trim control, a small pot that sets the final level of the direct out over a range of say plus or minus 20dB.


I agree most mixers have a monitoring section but here we are talking about a small budget project mixer but you are right, the API Box is little more than a couple of pre and a 24 track monitor section.

Cheers

Ian

 

[pucho812]

Having done it both ways direct out post fader leaves for the occasional opps, OI bumped the fader because a person couldn't sit still.