Compact desktop line mixer?

[Brian Roth]

Not necessarily. We don't really have a mechnaical design as such just yet except for perhaps a general acceptance of extruded rails held apart by cheeks.

Again, not necessarily. Many of the enclosure made by the synth boys have wood cheeks and I think I have even seen plastic ones.

Having said that, it may turn out the 3D printed cheeks are not strong enough but it is a great way to get small quantities of non-standard shapes so I think it is worth considering.

Cheers

Ian

One thing....the synth boys don't use wide panels, but instead a bunch of semi-narrow panels. The Eurorack rails provide easy module attachment while also helping the entire case from distorting into a 3-D parallelogram.

Bri

 

[OneRoomStudio]

There are plenty of nice mixers that were built this way. The cheeks could always be made of wood. Take a look at this Sound Workshop board - single panel, multiple channel boards:

 

[Brian Roth]

There are plenty of nice mixers that were built this way. The cheeks could always be made of wood. Take a look at this Sound Workshop board - single panel, multiple channel boards:
View attachment 144555View attachment 144556

Indeed! Did that mixer have metal behind the wood cheeks? Regardless, a "sorta thick" piece of custom-folded steel will be nice and sturdy and provide shielding.

Bri

 

[ruffrecords]

Hmm, that is interesting....and even more so if we don't need the rail system at all. If we used a single top panel for everything, but then kept the boards modular, we might not need them. Using @Brian Roth's initial "strip" pcbs for the faders, channel cards for the channels, and 2-3 pcbs for the master section (one for FX sends/returns, one for mix summing and mix insert, and maybe one more for monitor/headphone controls), it could still be "semi-modular." Still serviceable and customizable to some degree.

The only custom panels would be the top and the rear i/o...which would bring the price down significantly. For someone who hates metal work, that sure is a tempting direction to go in!

Exactly. This used to be a common method of semi-modular construction.

Cheers

Ian

 

[OneRoomStudio]

So just for fun, using that panel, with a 38mm channel width (~1.5"), and 100mm faders, we'd have around 120mm x 38mm for the channel controls, plus what looks to be plenty of room for the master section.

 

[MidnightArrakis]

Hmm, that is interesting....and even more so if we don't need the rail system at all. If we used a single top panel for everything, but then kept the boards modular, we might not need them. Using @Brian Roth's initial "strip" pcbs for the faders, channel cards for the channels, and 2-3 pcbs for the master section (one for FX sends/returns, one for mix summing and mix insert, and maybe one more for monitor/headphone controls), it could still be "semi-modular." Still serviceable and customizable to some degree.

The only custom panels would be the top and the rear i/o...which would bring the price down significantly. For someone who hates metal work, that sure is a tempting direction to go in!

[If we used a single top panel for everything] -- Bottom-line.....some form/manner/type of basic design concept needs to be decided upon and finalized before any further progress on any of this can be realized. And, of course, "Designed-By-Committee" will always be more difficult for any end result to be achieved.

I have already "mentally conceived" how this "Mini-Mixer" could be mechanically designed using a bare minimum amount of separate sheet-metal pieces. The "downside"???.....every sheet-metal piece is a custom-designed item. While that isn't a "BIGGIE" or even a concern for me with designing all of these sheet-metal pieces, designing this mixer in this manner would probably be more expensive, unless.....there would be a "group buy" for probably at least 12 or more mixers all at once.

Then, again.....I could also design this "Mini-Mixer" to be made all out of standard "rack-panels" as @Brian Roth has suggested, but then.....while using this approach may be somewhat less expensive, it then involves requiring many more pieces of metal and hardware in order to create the physical mixer itself. This then requires having to -- fit -- the various mechanical dimensions that make-up the mixer with having to conform to the specific dimensions of the individual rack-panels. And, that can become rather challenging to accomplish.

For those here who are somewhat "mechanically-minded challenged", here is a simple example. To design a "bottom-plate" for this mixer and then have it fastened to each of the side-cheeks, I could simply design a large panel that has a small flange bent-up on each side about 3/4's of-an-inch high. On each of these flanges, there could be maybe 5 of what are called "PEM-nuts" inserted into them that would be held in place by machine-screws going through a side-cheek. So, in this rather minimalist example, you end up having 3 pieces of sheet-metal and 10 machine screws --- 1 - Bottom-plate, 2 - Side-cheeks and 10 - machine screws.

By using the "rack-panel" method, you end up with 5 pieces of metal and maybe 18 machine-screws, like this:

• 1 - Bottom-plate (12U rack-panel)
• 2 - Side-cheeks (custom-designed)
• 2 - Rack-rails (Off-The-Shelf)
• 18 - machine-screws (5 X 2 = 10 machine-screws to hold the rack-rails to the side-cheeks + 4 X 2 = 8 machine-screws to fasten the rack-panel to the rack-rails

Or, am I missing something here, Brian???

In addition, and make note of this.....for every item that uses a "rack-panel" (i.e., mixing-surface top-panel (6U), connector I/O rear-panel (3U), headphone/iPad front-panel (1U), etc.) will -- ALSO -- require a pair of rack-rails and however many extra machine-screws to fasten the rack-rails to the side-cheeks and the rack-panels to the rack-rails. Whereas, a custom-designed piece of sheet-metal is merely -- designed-to-fit -- and then simply fastened to the side-cheeks as necessary. However, I am guessing that since the "rack-panel" approach is more like an "Erector Set" type of an assembly, that that will probably have a higher user appeal. Dunno!!!

Should I somehow feel so inspired, I could create some 3D CAD-images of each methodology which would allow those on here who are unable to mentally-visualize what it is that I am writing about here and "see" things in their own minds. However, my being on this forum is beginning to "wear me down" emotionally and mentally so..........I don't know right now. Maybe...............

/

 

[Brian Roth]

As I alluded in message #259, I no longer care what anyone does with this project. I will keep an eye on it but refrain from any comments. This has gone on 266 messages and nothing has been locked in. I question if enough agreement can be reached to create a group order of anything. Someone would have to take that financial plunge and hope they get their money back. Thanks to Ian, I learned a lot about the Eurorack "system" which I might find handy in some other future project.

The 12" of snow that fell here Jan 4/5 and trapped my vehicle in the driveway began slowly melting end of last week and should be nearly gone this week. Need to get caught up with some projects here.

Bri

 

[MidnightArrakis]

As I alluded in message #259, I no longer care what anyone does with this project. I will keep an eye on it but refrain from any comments. This has gone on 266 messages and nothing has been locked in. I question if enough agreement can be reached to create a group order of anything. Someone would have to take that financial plunge and hope they get their money back. Thanks to Ian, I learned a lot about the Eurorack "system" which I might find handy in some other future project.

The 12" of snow that fell here Jan 4/5 and trapped my vehicle in the driveway began slowly melting end of last week and should be nearly gone this week. Need to get caught up with some projects here.

Bri

[The 12" of snow that fell here Jan 4/5] -- Around this time of the year back in 1978 in Indianapolis, we had -- 5-feet -- of snow, THAT FELL ONTO AN EXISTING -- 3-feet -- OF SNOW!!! -- You can look it up on YouTube videos!!!

[and trapped my vehicle in the driveway] -- The late-night radio DJ on the main rock-station who was working his shift then, got snowed into the radio station facilities by himself and physically couldn't be reached!!! He ended up being On-The-Air around-the-clock for at least 3- or 4-days. During the days, he would just play entire albums one after the other and during the evening and nights, so he could finally get some sleep, he played 10-1/2 inch tapes of old news events, old recorded broadcasts of the "Indy 500" race and whatever else he could dig up. Because of the remote location of the studios and there being at least 8-feet of snow everywhere, the DJ was finally "rescued" about 4 or 5-days later, when some listener who had a motorized snow-ski vehicle was able to travel on top of the snow-mounds, reached the studios and was able to finally take him home. I didn't see my own car for at least a month or more until enough snow had melted and I could dig it out.

/

 

[ruffrecords]

[If we used a single top panel for everything] -- Bottom-line.....some form/manner/type of basic design concept needs to be decided upon and finalized before any further progress on any of this can be realized. And, of course, "Designed-By-Committee" will always be more difficult for any end result to be achieved.

At the moment, the OP is in the driving seat. He expressed an interest in a simple desktop mixer and many people have chimed in with ideas and suggestions for its electronics and mechanics. Judging from the OPs more recent posts it looks like he is homing in on a preferred route. Hopefully he will build it and document it here so others can repeat it or tweak it to their own needs.

Cheers

Ian

 

[ruffrecords]

snip
By using the "rack-panel" method, you end up with 5 pieces of metal and maybe 18 machine-screws, like this:

• 1 - Bottom-plate (12U rack-panel)
• 2 - Side-cheeks (custom-designed)
• 2 - Rack-rails (Off-The-Shelf)
• 18 - machine-screws (5 X 2 = 10 machine-screws to hold the rack-rails to the side-cheeks + 4 X 2 = 8 machine-screws to fasten the rack-panel to the rack-rails

Standard Eurorack extrusions (not the simplified ones used by synth builders) include a slot which can be used to hold a bottom panel as shown in post #20 of this thread:

https://groupdiy.com/threads/m3-self-tapping-screws.85355/

The 0.8mm thick steel panel is supported along its entire width (front and back) by the extrusions so at most you need a tapped cube at the half way point on each side to attached it to the cheeks.

Cheers

Ian

 

[OneRoomStudio]

Thanks, Ian. I appreciate the support. I think this form factor most closely matches my initial desires. I laid out the channels to see if they would fit. This is assuming I'm using board-mounted pots like these, and push buttons like these (with the switches mounted to the back of the board). Everything would just about fit. I still need to add peak-indicator and solo-indicator lights. Plus...need to finalize the functionality in the master section and lay that out too.

 

[OneRoomStudio]

@MidnightArrakis - Where did you find the 3D cad file for that enclosure? I can only find the 2D DXF/DWG and I want to get a better look at the extrusions used for the front and back. Thanks!

 

[MidnightArrakis]

@MidnightArrakis - Where did you find the 3D cad file for that enclosure? I can only find the 2D DXF/DWG and I want to get a better look at the extrusions used for the front and back. Thanks!

[Where did you find the 3D cad file for that enclosure?] -- Which enclosure? Be more specific as I have several 3D-images of various enclosures sprinkled around on this forum.

/

 

[OneRoomStudio]

[Where did you find the 3D cad file for that enclosure?] -- Which enclosure? Be more specific as I have several 3D-images of various enclosures sprinkled around on this forum.

/

Sorry, I meant the one we’ve been talking about most recently - the Takachi CF45-28

 

[MidnightArrakis]

Sorry, I meant the one we’ve been talking about most recently - the Takachi CF45-28

[Where did you find the 3D cad file for that enclosure?] -- Their online downloadable 3D CAD-file was one I had found to be corrupted, so.....because I had a direct inside sales-persons' e-mail address from some previous communications I had had about some of their other enclosures, I sent that person a message detailing their corrupted -- STP -- download file. A couple of days later, that person had e-mailed me an alternative 3D CAD-file in a different CAD-file format and that is what you see down below.

[the Takachi CF45-28] -- See below:

>> Front-panel extrusion as viewed from the
left-side:


>> Rear-panel extrusion as viewed from the
left-side:


>> Bottom-plate and left-cheek screwed into the rear-panel extrusion, from the left-side:


/

 

[ruffrecords]

The other evening I downloaded the cheek profile, scaled it to half size so it would fit my 3D printer and printed one. I came out OK. Now I have to decide should I get a bigger printer or could I come up with a pair of interlocking pieces to make one cheek??

Cheers

Ian

 

[OneRoomStudio]

[Where did you find the 3D cad file for that enclosure?] -- Their online downloadable 3D CAD-file was one I had found to be corrupted, so.....because I had a direct inside sales-persons' e-mail address from some previous communications I had had about some of their other enclosures, I sent that person a message detailing their corrupted -- STP -- download file. A couple of days later, that person had e-mailed me an alternative 3D CAD-file in a different CAD-file format and that is what you see down below.

[the Takachi CF45-28] -- See below:

>> Front-panel extrusion as viewed from the
left-side:
View attachment 144711

>> Rear-panel extrusion as viewed from the
left-side:
View attachment 144712

>> Bottom-plate and left-cheek screwed into the rear-panel extrusion, from the left-side:
View attachment 144713

/

Thanks, @MidnightArrakis. Would you be willing to share the working 3D file you have?

Also, not sure if anyone is following this with any interest anymore, but I (mostly) finished laying out a version of this project that would fit in that enclosure. Something like this:


Ultimately, I think a bicolor signal/peak LED per channel will be a lot easier than a true meter per channel (even though I'll miss it), and a stereo LED meter will still give it some metering. The layout isn't 100% locked in, but this would only require (8) channel PCBs, one FX send/return PCB, one monitor control PCB, and one for the mix bus, meter, and insert send/return. Plus fader strip boards...but those are pretty basic.

 

[JohnRoberts]

The other evening I downloaded the cheek profile, scaled it to half size so it would fit my 3D printer and printed one. I came out OK. Now I have to decide should I get a bigger printer or could I come up with a pair of interlocking pieces to make one cheek??

Cheers

Ian

Isn't it amazing what we can DIY now? I recall less than 20 years ago when I tooled up an injection molded case for my drum tuner I had to pay hundreds of dollars to get a prototype 3D printed before cutting the hard tool.

Think back to more than 20 years ago.... Hobbyists today don't appreciate how good they have it. Perhaps some do.

JR

 

[MidnightArrakis]

Thanks, @MidnightArrakis. Would you be willing to share the working 3D file you have?

Also, not sure if anyone is following this with any interest anymore, but I (mostly) finished laying out a version of this project that would fit in that enclosure. Something like this:
View attachment 144904

[Would you be willing to share the working 3D file you have?] -- I'll share you mine, if you will share with me yours!!! Is it FPD?

Which CAD-file format would you like to have? -- STP? IGS? FPD? SLDPRT? X_T? Let me know, OK???

/

 

[studio1117 RSS]

Thanks, @MidnightArrakis. Would you be willing to share the working 3D file you have?

Also, not sure if anyone is following this with any interest anymore, but I (mostly) finished laying out a version of this project that would fit in that enclosure. Something like this:
View attachment 144904

Ultimately, I think a bicolor signal/peak LED per channel will be a lot easier than a true meter per channel (even though I'll miss it), and a stereo LED meter will still give it some metering. The layout isn't 100% locked in, but this would only require (8) channel PCBs, one FX send/return PCB, one monitor control PCB, and one for the mix bus, meter, and insert send/return. Plus fader strip boards...but those are pretty basic.

Don’t refer to the cue send as FX3. It’s a CUE. Yes it can be used as “FX”…but it’s a cue. Also I see you have 3 monitor selections. They all need the ability to be trimmed. Actually I doubt seriously that you need 3 monitors to select from for an 8 channel mixer.
There seems to be some confusion as to who this mixer is for in the market. You have features that would be found on hugely expensive consoles and you are lacking features that would be found on inexpensive small consoles.
The other thing I’ve noticed, I’m guessing a large part of the people using this will be using it for summing. I find it interesting that there is absolutely no flavor on the inputs of individual channels, and you solely rely on a fixed style of output to get your “flavor“.
Might I suggest that all inputs(Main ins as well as the cues when they are used as 2nd inputs to allow the console to be 16 inputs for summing) be set up to allow for a 2520 style discreet amplifiers but be populated with a standard, modern 5534 equivalent and allow for the install of discrete modules should the builder opt for that extra flavor.
That brings up another point and that is I don’t see any place on your console to turn the CUE, as it will here forward be referred to, into secondary inputs for summing.
I just feel like in my reading of this thread that there is a want for a bunch of features that don’t really appeal to the masses and a lack of the features that would.
I think the output stage should be completely modular and a certain amount of space be allowed in the back part of the chassis to allow for a builder to decide if the builder wants the Jensen 990, Neve route, tubes, or as I’ve discussed with Brian Roth a way to use external API modules as your output amps. Seems a much easier way to have different flavors at the output stage.
The layout seems good, not sure why there is all of this discussion about 3D printing etc. this whole thing can be on a flat panel with silk or laser engraved into a folded metal box back (angled) Not sure why you are making the easiest part of the design into a rabbit hole of insanity. Just look at the LILO or the SSL. Nothing crazy.
And again…. 90% DB25 and a few other XLR, 1/4” etc. for in/outs. Unless you want this to look like a high school shop project of a mixer built in 1970