Compact desktop line mixer?

[Brian Roth]

Speaking of spaghetti....

I vote against ribbon cables running sideways connecting modules together. Ian pointed out that a defect anywhere means replacing the entire "string". While I haven't had failures here with the ribbons on our Neotek Elite desk, It's a PITA getting a module's cables "unstuffed" and restuffed.

I do vote for (per Ian's suggestion) a ribbon system to a backboard card, like the Eurorack synth boys use.

In a perfect world this design would have modules with edge connectors or DIN connectors mating with a "hard" motherboard. I leave that sort of mechanical design as An Exercise For The Reader. But downside....requires an extender card or harness to service in the desk frame, or a test jig for the service workbench.

Bri (my middle name can sometimes be KISS)

 

[kags]

Catching up on a lot of messages,,,

I didn't see any plates like that at Legrand/Middle Atlantic's kinda goofy website, Looks useful! Part number? Thanks!

Bri

The two-hole plate is called MA-2DB25 (of course!)
https://www.markertek.com/product/2db25/ucp-module-for-two-25-pin-d-subs

 

[MidnightArrakis]

More Metal Musings <g>......

A LOT of the metal work design elements are are easily available as catalog items. For instance:

https://schroff.nvent.com/en-gb/products/enc34560-084

Slide in the metal strip with all the mounting holes:

https://schroff.nvent.com/en-gb/products/enc34561-384

There's a bunch of other "Erector Set" Eurorack metal components available.

For those who weren't a child tinkerer...

https://en.wikipedia.org/wiki/Erector_Set

Side cheeks for this mixer project could be 1/4" aluminum cut into an irregular trapezoid or pentagon (hexagon.....yada) to define the profile. The extrusions act to hold the chassis together in the 3D world while also providing mounting points for the front panels.

The standard DIN rails max out at 84 HP length, but Ian mentioned the "Doepher" synth format allows longer rails...Need to research on what is available.

Only downside (?) is the module mounting holes are in 0.2" increments, 500 series modules won't work nicely.

I'm just slinging spaghetti against the wall to see if it sticks!

[schroff.nvent.com/en-gb/products/enc34560-084] -- See below:


[schroff.nvent.com/en-gb/products/enc34561-384] -- See below:


[There's a bunch of other "Erector Set" Eurorack metal components available] -- My parents had gotten me -- TWO -- of these large "Erector Set" kits when I was a child around 8 - 10-years old. I can (barely) remember building these really big "office buildings", school buildings and "mini-skyscrapers" as a kid!!! And, since my kits had also included a small motor and some gears, I also built movable "cranes" that could swivel-around and lift "construction" materials up to the higher-levels of the tall buildings I was building. Way back then.....there was no "vegging-out" while sitting around on a sofa playing video games!!! Your mind was kept active, creative and innovative designing and building stuff that came out of your brain!!! And.....HERE I AM TODAY!!!

[Side cheeks for this mixer project could be 1/4" aluminum] -- While I get your point about doing things this way, but wouldn't this still end-up being a rather bit on the "heavy" side of things???

[Ian mentioned the "Doepher" synth format allows longer rails] -- While this "synth" format allows for longer rails, Ian's "Front Panel Designer" program doesn't!!! I had requested that he provide me with a set of complete mechanical dimensions of what is needed and I could create whatever is needed within my SolidWorks program, as it doesn't have any size limitations, but I have as yet to receive a reply back from him. As an example, long ago I saw some TV news and YouTube videos of scores of the -- illegal immigrants -- scaling "The Border Wall" and I came up with a relatively simple mechanical design solution to resolve that issue. Those sections of The Border Wall that you see being lifted and set into place by cranes are 35-feet high by around 12-feet or so wide. I can create those sections at full-scale in my SolidWorks program because it doesn't have any size limitations. What I want to do is to create a section of The Border Wall at full-scale and incorporating my "Wall-Scaling Inhibitor" design into it and then send some 3D CAD-images to that Tom Holman guy who is now in-charge of Homeland Security. My point being, however.....is that my CAD-software doesn't have the limitations that Ian's CAD-software does.

[Only downside (?) is the module mounting holes are in 0.2" increments, 500 series modules won't work nicely] -- Once I know what it is that I am working with here in regards to this mixer project, I'm gonna try to see what I -- "might" -- be able to work out about this.

[I'm just slinging spaghetti against the wall to see if it sticks!] -- May I suggest that you try attaching some VELCRO to your wall first!!! You may end up being quite surprised by how much spaghetti gets and stays stuck to your wall!!!

/

 

[ruffrecords]

This is the message I received when I clicked on the link you provided in your reply:

Oops. Should be fixed now.

Cheers

Ian

 

[L´Andratté]

/.../

Could you please constrain political remarks to the section reserved for that
(and which I avoid for a reason)?
Please?

 

[Brian Roth]

Another possibility -
https://www.redco.com/Redco-DSUB-UCP-Module.html

After poking around there, I see panels with up to 4 db-25 openings. Missed that after my first glance.

Good to know there are possibilities! Thanks!!

Bri

 

[ruffrecords]

[I found it very hard to create a 104HP panel in front panel designer] -- Well.....Alrighty NOW!!!.....I think there could be an easy "work-around" to resolve this little issue of yours!!!

Provide me with a -- DETAILED -- mechanical sketch of your desired front-panel. Include -- ALL -- holes, slots, cutouts, etc. with EVERYTHING clearly dimensioned!!! I could then create your front-panel in SolidWorks to be however and whatever you want it to be and then I could do a "Save As" and save the design as an -- STP -- file. From there, I could import the -- STP -- file into Front Panel Designer and turn right around and do another "Save As" as an -- FPD -- file.

Many thanks for the offer but it is not me who is doing the detailed design of this; it is/will be the OP. As it now turns out we most likely will not need a 104HP wide panel so front panel design will be perfectly adequate.

Cheers

Ian

 

[ruffrecords]

The standard DIN rails max out at 84 HP length, but Ian mentioned the "Doepher" synth format allows longer rails...Need to research on what is available.

Most manufacturers do supply other lengths. You can even buy 1 metre lengths of extrusions which is exactly what Holger Classen did when he built his Krassemaschine 12 channel all tube mixer :



Cheers

Ian

 

[Brian Roth]

Many thanks for the offer but it is not me who is doing the detailed design of this; it is/will be the OP. As it now turns out we most likely will not need a 104HP wide panel so front panel design will be perfectly adequate.

Cheers

Ian

Indeed! Now I'm wondering if only one these will ever be built?

Nevertheless, it's been a fun mind exercise for me! Also it's been a blast kicking ideas around with you, Ian <g>

Bri

 

[ruffrecords]

Indeed! Now I'm wondering if only one these will ever be built?

Nevertheless, it's been a fun mind exercise for me! Also it's been a blast kicking ideas around with you, Ian <g>

Bri

It is great fun isn't it. I am more than happy to participate/help.

Cheers

Ian

 

[MidnightArrakis]

Could you please constrain political remarks to the section reserved for that
(and which I avoid for a reason)?
Please?

[Could you please constrain political remarks] -- 1) I have no idea to what it is you are referring to and, 2) Don't be so sensitive!!!

/

 

[MidnightArrakis]

Many thanks for the offer but it is not me who is doing the detailed design of this; it is/will be the OP. As it now turns out we most likely will not need a 104HP wide panel so front panel design will be perfectly adequate.

Cheers

Ian

[doing the detailed design of this; it is/will be the OP] -- I apologize!!! I had mistakenly thought that this was an entire "GROUP" designing effort. So.....everybody here just throws about various ideas and then the OP is the one who actually completes all of the mechanical and PCB designs for himself? I wasn't aware of that. MY BAD!!!.....

/

 

[ruffrecords]

[doing the detailed design of this; it is/will be the OP] -- I apologize!!! I had mistakenly thought that this was an entire "GROUP" designing effort. So.....everybody here just throws about various ideas and then the OP is the one who actually completes all of the mechanical and PCB designs for himself? I wasn't aware of that. MY BAD!!!.....

/

No problem. Design by committee happens here a lot. As you know, there is a huge breadth and depth of skills available in the members of this group. There are not many places like this where you can ask a technical question and obtain a raft of different alternatives in response. Often just one person ends up building the thing but sometimes a bunch of people will build it or their own version of it (my EZTubeMixer design is a case in point) but all contributions are welcome. There is no set format, it is just a bunch of like minded folk with similar interests shooting the breeze.

Cheers

Ian

 

[OneRoomStudio]

OK...packaging thoughts.

One big-ass front panel for the faders and/or channels is somewhat reasonable, but NOT one big-ass PCB for either/both. We are not Behringer (or SSL, etc) who can afford the money and time to get everything all mechanically lined up by doing multiple prototype iterations. "Damn....faders 1-4 work kinda OK but things drifted and faders 5-8 are dragging on the front panel slots." etc etc

That's why I suggested individual little "strip boards" for each fader that is mounted on a PCB. The TKD "style" faders directly mounted to the plate would be a similar thing.

Similar thing for the input pots and switches if directly soldered to the PC boards. If someone wants to layout the panels and PCBs, pay to order prototype metal work and PC boards and front panel controls and assemble the mess and PRAY everything lines up (lather/rinse/repeat if wrong)...then go for it! It's not my money and time. lol

FWIW, the pots on the SSL 4K desk's input strips used wire jumpers to the corresponding PC boards...no alignment problems there!

I am just trying to reduce the design complexity (and eliminate the requirement of single-sourced parts to make everything fit together). Not as much of an issue for a one-off, but we are effectively doing a production run.

More comments in a "minute" <g>

Bri

Going back to this one for a moment (sorry, now I'm catching up).

I totally agree with you about the one-big-pcb for the channels. That's a terrible Idea for lots of reasons, which is why I suggested one panel, but 8 individual channel cards (mounted to the panel) for the channels.

For the faders though, I don't think it's too difficult to put them all on one PCB behind one panel. Yes you have to line up 8 slots...but with modern CAD, that's really not hard to do.

 

[hitchhiker]

Really enjoying this thread. I have some lovely long throw 600 ohm audio taper P&G faders and I'm wondering would the THAT 1200 be able to drive 600
ohms without too much of a penalty?

 

[Ike Zimbel]

Speaking of spaghetti....

I vote against ribbon cables running sideways connecting modules together. Ian pointed out that a defect anywhere means replacing the entire "string". While I haven't had failures here with the ribbons on our Neotek Elite desk, It's a PITA getting a module's cables "unstuffed" and restuffed.

I do vote for (per Ian's suggestion) a ribbon system to a backboard card, like the Eurorack synth boys use.

Pardon the topic swerve, but I actually sketched out this exact arrangement for the Neotek Elite and ran it past Sytek (owners of the Neotek line now). It was a series of mother boards that would provide all of the bussing etc, but each module would connect with 4 (IIRC) 16-way 0.100" female-female ribbon cables to the backplane instead of its neighbours. This was partly because it was WAY easier to get those 1' cables made, than to get the custom ribbons made. It also offered opportunities for improvement like better power distribution, and local bulk PS decoupling every so many modules (I think the boards were meant for groups of 8 i/o's...it's been a while).

 

[OneRoomStudio]

Really enjoying this thread. I have some lovely long throw 600 ohm audio taper P&G faders and I'm wondering would the THAT 1200 be able to drive 600
ohms without too much of a penalty?

600 ohm might be a bit on the low side. Some of the application notes spec it down to 2k, but I've never seen anyone driving lowe impedances than that directly off the line receiver. You might need an additional buffer stage.

 

[OneRoomStudio]

Pardon the topic swerve, but I actually sketched out this exact arrangement for the Neotek Elite and ran it past Sytek (owners of the Neotek line now). It was a series of mother boards that would provide all of the bussing etc, but each module would connect with 4 (IIRC) 16-way 0.100" female-female ribbon cables to the backplane instead of its neighbours. This was partly because it was WAY easier to get those 1' cables made, than to get the custom ribbons made. It also offered opportunities for improvement like better power distribution, and local bulk PS decoupling every so many modules (I think the boards were meant for groups of 8 i/o's...it's been a while).

That's making me think (along with the comments from @ruffrecords and @Brian Roth) that we might be able to "kill two birds with one stone" by making the rear panel PCB also the bus PCB.

@Brian Roth - I know you said you prefer to wire connectors, but man, I hate unnecessary wiring. I've used pcb-mount jacks in lots of projects, and as long as they are both board-mounted AND panel-mounted, I've had zero issues. If the rear panel PCB was both bus and i/o, the channel cards (each) would only need one 3-wire connection to the fader PCB, and one 15-conductor ribbon to the rear pcb (specific pinout TBD):

1) Mix L
2) Mix R
3) Aux 1
4) Aux 2
5) Aux 3L
6) Aux 3R
7) AFL Bus
8) AFL Relay
9) Line Input +
10) Line Input -
11) Audio Ground
12) +16V
13) Power Ground
14) -16V
15) Meter Signal (?)

The master PCB (including Aux masters, FX Returns, Mix bus inserts, summing amps, and Mix outs) could connect to the same board with the same ribbon.

 

[Brian Roth]

Going back to this one for a moment (sorry, now I'm catching up).

I totally agree with you about the one-big-pcb for the channels. That's a terrible Idea for lots of reasons, which is why I suggested one panel, but 8 individual channel cards (mounted to the panel) for the channels.

For the faders though, I don't think it's too difficult to put them all on one PCB behind one panel. Yes you have to line up 8 slots...but with modern CAD, that's really not hard to do.

I have been trying to suggest a system that is not a "one trick pony". What if someone wants more, or less, channels for THEIR ideal mixer?

What if someone has their own (or has access to) metal working machines, but are older and non CNC controlled? When I used to build custom gear, I worked with a friend with his own metal shop and some splendid older machines like a gigantic Bridgeport vertical mill. He did very accurate work for things like rectangular holes in a panel to allow various console modules to be racked. A couple of times he cut very clean, narrow slots for the handle of a fader to go through a panel without rubbing. But, those faders were individually attached to the panel.

I may be overthinking this while trying to allow plenty of flexibility in construction....convenient building blocks. You can call it "granularity". Hell, nail the faders to a piece of 2x6 lumber for all I care <LOL>.

Just trying to avoid "thou shall use only this exact PCB attached to these exact single-sourced metal parts" vs. allowing the builder to do a bit of their own reasonable tweaks and use their own tools.

I don't have any dogs in this hunt. IMHO we seem to be closing in on a feature set and signal flow that makes sense for this relatively specialized gizmo without requiring a ton of moolah.

Bri

 

[Brian Roth]

Pardon the topic swerve, but I actually sketched out this exact arrangement for the Neotek Elite and ran it past Sytek (owners of the Neotek line now). It was a series of mother boards that would provide all of the bussing etc, but each module would connect with 4 (IIRC) 16-way 0.100" female-female ribbon cables to the backplane instead of its neighbours. This was partly because it was WAY easier to get those 1' cables made, than to get the custom ribbons made. It also offered opportunities for improvement like better power distribution, and local bulk PS decoupling every so many modules (I think the boards were meant for groups of 8 i/o's...it's been a while).

Sounds like a great idea!

The 48 channel ELAN (I said we had an Elite) here in Salina was pre-owned and it's been reliable. But, after it arrived I did have to tear it down to give most of the rotary pots a tiny sip of Tefrawn and do a simple mod to make the metering useful for live-to-two-track recording without the need to have a multitrack machine. I learned how to wrangle those ribbons....requires 2 or 3 to be removed at a time.

The desk has been in use for 9 years now and I can recall only one time I had to pull a module for repair (bad opamp). FWIW, this desk was from the Martinsound era.

Bri