Potato Cakes

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #20 on: November 07, 2019, 02:33:44 AM »
So I did this sorta. Kind of a blend. API meets Neve.
Check out
https://groupdiy.com/index.php?topic=62302.0
I used 990s and app DOA's to keep in line with the 24v needed for the Neve boards I used for summing. Ian Thompson Bell (former Neve tech) pretty much walks me through everything

Where did you end up with your buss resistor values? I have been reading Ian's info for his DB25 passive summing, but it is for balanced connections whereas I will be summing unbalanced signal from the NV circuit.

I'm going to try to meet with the guy doing the board layouts next week. I just need to compile my notes before then.

Thanks!

Paul


Rocinante

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #21 on: November 07, 2019, 11:20:34 AM »
15k I believe but let me check my notes. It might be 47k but I do remember I had to play around a bit and got help. I created a junction board to send the signals to the main, aux, metering and monitor outs that I would be happy to send you for ideas and for you to mess with. I also created a back plane to fit the API type input cards.
If there's a harder way to do this, I haven't found it yet.

Rocinante

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #22 on: November 08, 2019, 02:45:11 PM »
I was off. It is either 10k or 4k7. I'd have to open it up to know which. I think 10k offered better noise but I am not 100% what I chose.
If there's a harder way to do this, I haven't found it yet.

Potato Cakes

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #23 on: November 08, 2019, 03:48:59 PM »
Copy that. Since this is a scalable design to be used with a summing amp of the builders choice, there will be some level of buss resistors computation that will fall on the end user. 10k is one of the values I want to try for my initial build. This is to be a DIY project, so the builder will have to know or do testing to find out what the input impedance of their summing amp is and proceed accordingly.

Thanks!

Paul

Potato Cakes

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #24 on: November 11, 2019, 04:44:46 AM »
Tomorrow I am scheduled to meet with the PCB designer with all of my drawings and get the ball rolling on getting these boards made. Here's where I've ended up:

- VTB9045/46M or EA-10468 on board foot print with user selectable jumpers for preferred series/parallel winding configuration. You can also use these same pads to wire a mute.
- on board switch for Mono/Stereo. Can be wired off board or wired to a pan control.
- trimmers for feedback gain and attenuation, which can be wired off board for level control
- expansion input from additional boards
- sized to fit two boards (16 channels), summing amp, output transformers, and PSU in a single rack space enclosure. This will depend on size of output transformer, summing amp PCBs, and number of front panel controls used

Is anyone else interested? I do not know the price at which to sell these at this point. I can't it would be more than $50 USD but no promises.

Thanks!

Paul

Rocinante

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #25 on: November 11, 2019, 10:07:23 PM »
Why not design them yourself or have one of us work with you?  Eagle is a great program and can be learned relatively quickly. I have the full version as i use it a lot but you can download the free version which is still very good
« Last Edit: November 11, 2019, 10:12:40 PM by Rocinante »
If there's a harder way to do this, I haven't found it yet.

Potato Cakes

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #26 on: November 12, 2019, 03:53:57 AM »
Why not design them yourself or have one of us work with you?  Eagle is a great program and can be learned relatively quickly. I have the full version as i use it a lot but you can download the free version which is still very good

I did try to learn for myself a while back and I was very frustrated at the learning curve as nothing that I was doing from the tutorials seemed to translate to some of the simple circuits I wanted to make layouts. And since I'm fairly involved in a number of things I am trying to finish/accomplish, farming this part out is best. The guy I've been using is very good and boards I get from the Gerbers he generates are correct the first time. Plus, he's great to work with and I do wind up learning from him on each project, so I don't mind paying for that. For me, right now, trying to add learning how do my own PCB would be a bridge too far. Maybe someday...

Thanks!

Paul

Rocinante

Re: PCBs for scalable DIY Neve style summing mixer possible feeler
« Reply #27 on: November 12, 2019, 12:44:08 PM »
I get that. I hardly have time to type this. I'm intrigued to see what you come up with.
If there's a harder way to do this, I haven't found it yet.


 

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