Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #20 on: May 07, 2016, 01:30:28 PM »
From the looks of it the insert appears to be post gain (at A-9 thru A-11 I believe).  The direct out I had figured would just split off the circuits out so yes that too would be post gain


As to the answer to your second question; everything in the  studio is balanced so i should keep it that way if i can.

Edit*  I wanted to get Forthmonkey's permission (even though I was fairly certain he was okay with it) before posting the schematic to his channel boards:



« Last Edit: May 07, 2016, 03:28:37 PM by Rocinante »
If there's a harder way to do this, I haven't found it yet.


ruffrecords

Re: Another Neve 1272 summing mixer.
« Reply #21 on: May 07, 2016, 05:33:08 PM »
From the looks of it the insert appears to be post gain (at A-9 thru A-11 I believe).  The direct out I had figured would just split off the circuits out so yes that too would be post gain


As to the answer to your second question; everything in the  studio is balanced so i should keep it that way if i can.


OK, I still, think you are thinking too much about implementation  (answer 1) rather than what you want (Answer 2).

Think about the signal flow. A balanced signal comes in to a channel There's and insert and a direct out. You prefer these to be be balanced. Somewhere there is a channel fader and a pan pot. Think about how you want to use this mixer. Do you want the the insert pre or post the fader? Do you want the direct out pre or post the fader?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #22 on: May 07, 2016, 10:03:30 PM »
I suppose both pre fader. When i look at normal mixing console schematics though i see the inserts are usually post fader (right?) so i guess i thought this was necessary.  Considering most if not all of my gear is balanced so pre fader should be fine though right?
Same for the direct outs?
Please excuse the newbie question; but whats the benefit of having them post fader?


If there's a harder way to do this, I haven't found it yet.

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #23 on: May 08, 2016, 12:21:37 PM »
I just found several line mixers that have the inserts and direct outs pre fader but post gain.  I guess that makes the most sense.  One of the reasons i grabbed 10 channels of Forth Monkey's api channel summing boards was because ot seemed like an all-in-one solution for what I wanted considering it would provide fader, pan, inserts, mute and outs per channel all in one small board.  Considering yhe functionality i thought it would be a good platform to build off of.
If there's a harder way to do this, I haven't found it yet.

ruffrecords

Re: Another Neve 1272 summing mixer.
« Reply #24 on: May 08, 2016, 07:14:09 PM »
I suppose both pre fader. When i look at normal mixing console schematics though i see the inserts are usually post fader (right?) so i guess i thought this was necessary.  Considering most if not all of my gear is balanced so pre fader should be fine though right?
Same for the direct outs?
Please excuse the newbie question; but whats the benefit of having them post fader?

No problem. Lot's of desings put the direct post fader but personally I cannot see the point. The purpose of the fader is to set the MIX level from the channel

You can simplify your system somewhat. You have a balanced input XLR. You wire this to a regular half normalled balanced insert - you can add an insert bypass switch if you wish. The balanced output of the insert goes straight to your direct out so all these things happen pre-fader. The output of the insert also goes to the unbalancing amplifier (Forth Monkey's board), then to the fader and then to the pan pot and the L/R buses. You could also connect a couple of AUX send pots to the fader and feed them to AUX buses. As long as you use virtual earth mixing this will work well.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #25 on: May 08, 2016, 08:16:53 PM »
Ian,
I wish i could triple like a post as that last one cleared up the cob webs a good deal.  I will begin drawing it tonight.
Thank you.
If there's a harder way to do this, I haven't found it yet.

ruffrecords

Re: Another Neve 1272 summing mixer.
« Reply #26 on: May 09, 2016, 05:07:27 AM »
Ian,
I wish i could triple like a post as that last one cleared up the cob webs a good deal.  I will begin drawing it tonight.
Thank you.

Back in the 70s I worked in Sales Engineering at Neve where we designed Neve custom consoles. It was my job to talk to the console users about what they wanted the console to do - they were not interested in how we implemented  it. So it is good to hear I can still mamge to blow the cobwebs away.

Now ask yourself exactly what you want the direct out for.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #27 on: May 09, 2016, 11:09:39 AM »
I can tell you right now the direct out is by no means necessary just more of a convenience.  I do not feel too strongly about it.  Typically I have my consoles channels 1-16 direct outs connected to  patchbays which are then connected to my ad converter.  This makes it so at any time during mixing I can patch right in using my outboard and if needed treat the recorded track to whatever effects I need.  Sometimes when I am working with high track count sessions (40 or more in and out) this is necessary as my processing is being a little jiggy.  I understand that I could just have my channels go from da converter to patchbay to ad converter should I need to rerecord anything.   So I suppose having direct outs is mute and actually unnecessary unless they were transformer balanced and I was trying to add some 'flavor'. 
If there's a harder way to do this, I haven't found it yet.

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #28 on: May 09, 2016, 01:24:19 PM »
So like this:

 ::)

*Modified and edited*


« Last Edit: May 10, 2016, 03:27:50 AM by Rocinante »
If there's a harder way to do this, I haven't found it yet.

ruffrecords

Re: Another Neve 1272 summing mixer.
« Reply #29 on: May 10, 2016, 08:07:48 AM »
That's looking a lot better. You might like to think about whether you want the AUX send to work when the channel is muted .

Attached is my version of the input end. The input comes in on the XLR on the left and is connected to the balanced insert send jack. Because you can connect this to the input of another piece of gear without interrupting the signal we used to call this a 'sniff' at Neve. It could therefore double up as a direct out if you wanted. This jack is then connected to the balanced insert return jack in such a way the the input signal is disconnected from the return jack if something is plugged into it. This is what I know as a half normaled insert. The return jack is then connected to the direct out XLR (which could be a jack) and then it goes off the the balanced input of Forth Monkey's PCB.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'


Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #30 on: May 11, 2016, 12:33:10 PM »
Revised using your input scheme Ian and added output section.  I am still working out  which circuit I can use to use the b338's and b340's for my monitor and aux sends and returns.  I guess I could just use each half of the 3405 circuit....





 
If there's a harder way to do this, I haven't found it yet.

ruffrecords

Re: Another Neve 1272 summing mixer.
« Reply #31 on: May 11, 2016, 05:17:06 PM »
Getting better all the time.

What do the master stereo send and returns do?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #32 on: May 11, 2016, 07:13:44 PM »
Inserts for the master bus so i can use various comps and eqs. Probably not correct huh?
Id like to have two inserts but id be alright with one.
If there's a harder way to do this, I haven't found it yet.

ruffrecords

Re: Another Neve 1272 summing mixer.
« Reply #33 on: May 12, 2016, 06:21:32 AM »
Inserts for the master bus so i can use various comps and eqs. Probably not correct huh?
Id like to have two inserts but id be alright with one.

OK, understood. You can do them just like the insert on each input. No need for extra amplifiers. If you want two just wire them in series.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #34 on: May 17, 2016, 12:25:27 PM »
Thanks Ian Ive adjusted it.
As a little update Forth Monkeys 'summer channel boards' (which is what I'll call them from now on) have arrived. Decent quality for sure.
Awaiting the parts to stuff them including 50k pan pots of which I'm gonna use alphas and add leads to them so they fit the foot print. The footprint is for Omeg 47k dual pots which are a tad expensive here in the states but I might grab some over time. I'm trying to find some nice 5k log pots like bourns or vishay but for now will be using alphas there as well.
Martins EZLN 72's are stuffed and waiting.
JLM had a lot of what ive needed since much of what Joe makes is 24v (including opamps) and 'regurgitators' and i am awaiting stuff from them.
I've got my eyes on ebay for transformers but it looks nore than likely either hairball or aml.
I also have a basket with amphenols, doa sockets, and grayhills at capi i need to order.
Progress.

If there's a harder way to do this, I haven't found it yet.

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #35 on: May 21, 2016, 01:12:01 PM »
Okay so as i understand it:
I should literally tie the aux fader 'in' to the 'out' of the volume fader.  The aux fader 'out' goes to the aux bus.  I should then tie the aux ground to the volume fader ground.  Auxes generally seem to follow log law and most schematics I have seen have them usually sharing the same tolerance as the volume fader (with several exceptions naturally) which in this case is 5k.  Tying the aux fader directly to the volume fader will  also makes it easier for the front panel.
So far so good?
For my insert bypass switch I am going to wire it like on the helios bypass and connect it to the insert sends, thus cutting only the insert off and nothing else.
Sound right?
I hit a small snag with the 3.96 pin size, the summer channel header tab size, and header options but I found a workaround albeit with a little work/time involved.  I am going to try several boards using amphenol 30 pin and a bunch with molex headers to see which is more elegant and more importantly easier to troubleshoot.  I may use both.
If there's a harder way to do this, I haven't found it yet.

ruffrecords

Re: Another Neve 1272 summing mixer.
« Reply #36 on: May 21, 2016, 04:39:48 PM »
I am not familiar with the Helios bypass so I cannot comment on that.

Regarding the AUX send pot, yes you connect the top of the AUX fader to the slider of the channel fader. However, you need to watch the total laod i=on the Forth Monkey board.  If the channel fader is fully up, the Forth Monkey board has to drive the parallel combination of the 5K fader, the pan pots and the AUX pot. You also need to think about the effect that the load due to the pan pots and the AUX pot will have on the law of the channel fader. To minimise both problems it is a good idea for the AUX pot to be several times the value of the fader. Notice that the pan pots are 50K. There's two of them in parallel which makes 25K and there's a 10K pull up and the 47K bus resistors. All together, the pan pot load is about 7K. I would therefore recommend you make the AUX send pot at least 22K.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #37 on: May 21, 2016, 05:55:58 PM »
Ian thank you.  Several questions i had rolling in my noggin were answered in your brief response.
 I should have been more specific regarding the Helios bypass.  I meant specifically how the bypass switch is wired on the Helios filtersyou designed  (which is the same as original as well as other designers) I just dont know the name for it.
And that's what the internet is for.
Thanks again.
If there's a harder way to do this, I haven't found it yet.

ruffrecords

Re: Another Neve 1272 summing mixer.
« Reply #38 on: May 21, 2016, 06:57:16 PM »
Ian thank you.  Several questions i had rolling in my noggin were answered in your brief response.
 I should have been more specific regarding the Helios bypass.  I meant specifically how the bypass switch is wired on the Helios filters you designed  (which is the same as original as well as other designers) I just don't know the name for it.
And that's what the internet is for.
Thanks again.

OK, understood. That type of bypass only works for unbalanced signals. To properly bypass a balanced insert you need to switch both the hot and the cold signals.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

Rocinante

Re: Another Neve 1272 summing mixer.
« Reply #39 on: May 22, 2016, 11:40:00 AM »
I believe I found a really clean solution with the added benefit of using relays.  Our Russian friend at Diy-Tubes seemed to have just what I needed
Here is the schematic and how I would apply it.  It's intended use is as a bypass in effects units but I believe this will work and it certainly would make life much easier.




If there's a harder way to do this, I haven't found it yet.