Potato Cakes

Hello, everyone,

I'm thinking about adding a summing mixer of some sort to my console to add options for things like mixing stems to better suit a variety of sonic demands/requests from clients. The CAPI SumBuss looks awesome and my plan was to go that route, but the mods on my console's channels and the mix buss lend itself in that direction. Lately I've been enjoying my Neve style preamp/EQ builds and I've decided if this idea moves to board design it will be in this direction. Here's the initial design ideas:

Boards will be in banks of 8 input channels. Each input channel will have a footprint for a VTB9045M or mounting holes for an EA10468 and a BA189AV circuit for adjusting gain to user specific settings. PCB dimensions will be so that two of them and two BA283AM circuits could fit in a 1U case approximately 11 inches deep with relative ease. The 283AM circuit will not be on the board for as there are already various ones of them available that work great and this also allows for using various mix buss circuits like the ACA-BO. My initial thought is to have a push button toggle on board for mono/stereo settings for each pair of inputs. If someone desired they could incorporate pan, volume, etc., controls but they will have to be wired off board to so as to keep the PCB size to a minimum.

I'm going to start casually compiling my notes from previous Neve builds come up with some crude layout ideas to then take the board designer I've been using. Probably the one item of business that I need to make certain of is the buss resistor value. I've previously used 15k with a fair amount of success but noticed a fair bit of cross talk, which may be normal for older Neve mixer circuits. Has anyone found better/different good results with other values? Everything else I am trying to do seems a bit straightforward.

I'm curious if this is of some interest to anyone besides myself. I've used these same buildings block circuits on other projects and the results were exceptional, so I have no reason why this won't sound great as well.

Thanks!

Paul


Thro

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #1 on: July 03, 2019, 04:43:34 PM »
Great idea, i was just thinking about doin this with the ez 1290 pcbs and line input transformers

KDE

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #2 on: July 15, 2019, 03:52:47 AM »
Love the idea and would be interested in making a 32 channel box. My questions also is why not use the line input transformer?
Some things are best left unsaid

Potato Cakes

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #3 on: July 15, 2019, 05:27:46 AM »
The line in version is an option, but as seen in a number of Neve style preamp designs the line input transformer is done away with and unity gain is still achieved. I'm also thinking about a way of making each channel input have a slightly higher gain setting then attenuate it before it goes to the summing amp, that way at unity gain on the output, the channel is saturated slightly. If I'm using the mic transformer version then I can set the initial channel gain at the transformer. This is the part that will require some experimenting and listening to see where this saturation/distortion is to occur, or if it's even desirable at all.

As mentioned, this is a little ways down the road. I'm merely trying to gauge if this is something that I'm going to do just for myself.

Thanks!

Paul

KDE

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #4 on: July 17, 2019, 04:36:42 AM »
Gotcha ya put me down i'm interested.
Some things are best left unsaid

ilfungo

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #5 on: August 14, 2019, 02:20:55 PM »
Great Idea!


 

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