Another Neve 1272 summing mixer.

[Rocinante]

Master/control section. The large pushbutton without text is the stereo bus insert switch. The little pushbutton is headphone which is ebgraved above it but shadows block it out. Master is the top right below that is monitor. The far left gray knob selects monitor a or b  then volume control for dim and headphones. Aux return is the final gray knob.

https://postimage.org/

 

[Rocinante]

I am still playing with a teensy so i still may incorporate some digital control via an additional 1u monitor controller that can get incorporated with it. Basically the same thing as the master section but digital and in the daw if one were so inclined. I am still designing the 2u 19" led metering that will attach either via cat cable or db25.  It will feature an led meter that sits above the channrl plus an additional two larger vu meters as a monitor out.
I envisioned using an artist mix or one of the new icon m-platforms (or a modified x-touch) that sits below everything.

 

[Rocinante]

Oh and eight of Ian's Helios eq's maybe between the vu meters and mixer.
That icing would make it close as I'll  ever get to my dream set up.

 

[Rocinante]

The distribution pcbs finally arrived.


http://postimage.org/app.php

 

[r2d2]

...ops , seem image has disappeared  ???

 

[Rocinante]

Thanks man. Fixed.

 

[r2d2]

...ops , seem image has disappeared  ???

still missing
r

 

[Rocinante]

Yeah i dont know why that disappeared
https://postimage.org/

 

[Rocinante]

As a quick progress report:
The left summing side is being iffy but i have broken my femur and currently cant get to it to work on it.

 

[Rocinante]

Okay I had needed to take a break.  Frustration, incompetence, health, work, moving shop, blah blah blah have kept me from moving forward.  And then my dog died and I broke my leg. 
blah blh blah.
But I am finally able to  get back to this.
Currently the mixer is in pieces on the bench.  And I need to go back to the beginning.
So here's my first problem;
I had been having problems with the channel cards and yes I should have just figured it out awhile ago but i decided to move forward.
My signal seems to stop after the pan pot.
Up until now I had just went out the insert out (and actually forgot what i had done) as I wanted to move on and figured I would get back to it.  The DOA's are definitely working and are influenced by the fader.
Something is wrong.
Here is an image of the channel card with the values I am using right now.
On R7 and R8 it said 22k in one schematic and 47k in another.  I tried both and right now have a channel with 4k7 resistors at R7 and R8 and another with the rest of the channels at 47k. 
Nevertheless the signal seems to stop at the out legs of the pan pot.
Could someone see if something is weird?  Or wrong?  I'm dumbfounded.
https://postimage.org/

 

[pahstah]

Hi Rocinante,
I don't remember the pin out of the 500 series to be like that. Maybe i read it wrong but isn't pin 15 supponed to be 48v? And output should be pins 2-3-4, pin 5 is audio ground so that's why no signal out. i don't know but that goldfingers pinout seems somewhat strange to me.

Paolo

 

[Rocinante]

Forth monkeys 'api summer channel boards' dont subcribe to the 500 series format.  I had to design and build a backplane to fit it.  To be honest i had to file down the connector quite a bit as well as straighten and widen the 3.96 pitch holes to be 3.96.
I found the problem though and hense why some channels worked. With the 25k aux pot all the way down i get signal through the card.
I'm not sure how to continue.
Presently i have the aux being fed directly from the 5k faders 1 and 3 legs. The aux pot's middle leg feeds the aux bus.
Soooo....
Do i build a small aux amp per board?

 

[pahstah]

ok, now i see

 

[ruffrecords]

You need to make sure to 0v end of the auxes pot goes directly to 0v to minimise the off resistance.  Do not daisy chain it to the fader 0v.

Cheers

Ian

 

[Rocinante]

Ian,
Thank you.
I'm on it.

Fwiw: i had a bad vintage 3055 on one of the Neve summing boards that I'm currently replacing.  Lots of parts to keep in mind is an understatement.

 

[Rocinante]

Alright so audio signal is going through the entire system.
Now to rewire the other 10 channels.

 

[ruffrecords]

Ian,
Thank you.
I'm on it.

Fwiw: i had a bad vintage 3055 on one of the Neve summing boards that I'm currently replacing.  Lots of parts to keep in mind is an understatement.

There is a lot of myth and lore surrounding Neve amps. The bottom line is Rupert is a great believer in the use of negative feedback to reduce the effects of component tolerances but if you tell that to the golden ears brigade it falls on deaf ears.

Cheers

Ian

 

[Rocinante]

Man I'm busy. Alright so i am rewiring the aux pots and got to thinking again about the two 47k bus resistors (R7 and R8) on the 'channel boards'.  I read that many Neve consoles used 15k bus resistors.  Before i put it all back together i thought maybe i should put 15k in there instead?

 

[Rocinante]

Wow I just realized I haven't updated this in a while.  Life has been busy, work is busy, music is busy. Okay so it works.  I've got all but 2 channels working perfectly.  I made a few mistakes on the summing boards with my gain steps and so my right channel is not in line with my left.  I got to work that out.  I've actually played around with it quite a bit and it sounds pretty damn good.  I'll post when I get further along or finished. Almost there.

 

[Whoops]

There is a lot of myth and lore surrounding Never amps. The bottom line is Rupert is a great believer in the use of negative feedback to reduce the effects of component tolerances but if you tell that to the golden ears brigade it falls on deaf ears.

Cheers

Ian

Right.

Also don't tell the brigade Neve just used off the shelf parts and that the transistors where never selected.

People still believe the transistors need to be selected for a specific beta