Open source project: Customized mixing console

[Brian Roth]

To be honest, I didn't think so much when I started this project. The PCB drawing was just based on the free manufacturing standards of jlcpcb (the PCB manufacturer that developed EasyEDA) (within 10X10cm). But now, as the project gradually becomes larger, It seems necessary to build modules that comply with the standards. Are there still problems with the preamplifier part? If not, I will redraw the schematics and reset all designs to 500 module standards.

I have several BIG problems with the 500 module format for a project like this! The 15 pin edge connector format means very limited input and output connectivity. So, no places on the connector for things like insert sends/returns or buses.. The 500 format was designed decades ago for very specific requirements of the API desks of that era and was never intended to be a universal format. For instance, you require MANY connection pins for busing. 15 pins "isn't enough"!

Hold off before before revising all your work to match the very limited 500 format!!!!! I'm still thinking! The Eurorack comes closer because you are not locked into only 15 pins per module.

Bri

 

[Brian Roth]

My Dumb Idea of the Day. A "superset" of the Eurorack standard as seen here:

https://noiseengineering.us/blogs/loquelic-literitas-the-blog/how-to-plug-in-a-module

Say, an 18 pin (or more?) connector that can't be accidentally plugged into a synth module. This "New Standard" can also have pins for feeding 48 Volt phantom which is NOT in the Eurorack standard. The "new standard" would also use something like +/- 18 VDC power rails.

@mmadu I am just throwing ideas around. I am also scaring myself! lol

Bri

 

[mmadu]

My Dumb Idea of the Day. A "superset" of the Eurorack standard as seen here:

https://noiseengineering.us/blogs/loquelic-literitas-the-blog/how-to-plug-in-a-module

Say, an 18 pin (or more?) connector that can't be accidentally plugged into a synth module. This "New Standard" can also have pins for feeding 48 Volt phantom which is NOT in the Eurorack standard. The "new standard" would also use something like +/- 18 VDC power rails.

@mmadu I am just throwing ideas around. I am also scaring myself! lol

Bri

Very good advice! How about using the 500 format for the preamp/EQ/compression section and the EuroRack format for the fader section? Quite a few effects modules use the 500 format (Rupert NEVEs / SSLs or Maags) so people can build their own effects chains at will (kind of like SSL X Desk)

 

[gyraf]

..we actually have our own revised standard here at groupdiy: The GroupDIY 51x Alliance

E.g. the 511 system: https://groupdiy.com/threads/the-official-groupdiy-511-help-support-thread.37438/

 

[mmadu]

..we actually have our own revised standard here at groupdiy: The GroupDIY 51x Alliance

E.g. the 511 system: https://groupdiy.com/threads/the-official-groupdiy-511-help-support-thread.37438/

Wow, another great choice, 24V power supply will open up more possibilities (vintage Neve modules, Neumann/API op amps or even tubes!) I think,,, I will use the 51X standard on the backplane connector , so that people can get more possibilities!

 

[MidnightArrakis]

I see that you are using the "EasyEDA" program for your schematics. Here is something for you to think about when using the "EasyEDA" program that has recently come to light here on this GroupDIY forum.....-- apparently, there is a "glitch" within the "EasyEDA" software that causes connections in the schematic to -- NOT -- be connected within the PCB-design program!!! >> NOT GOOD!!! <<

One member of this forum just had some PCB's fabricated from GERBER files generated by "EasyEDA" only to discover several components as being -- NOT -- connected in the layout, although they were connected in his schematic. If only this member had known about - me - and had sent me his GERBER and N/C Drill data files first before having them fabricated, I could have processed his output files through my "GERBER File Analysis" program and its "DRC" routine would have picked-up this error beforehand!!! Just sayin'.....

Before you become too involved with your circuit design and schematic drawing, I would -- strongly suggest -- that you download and install the latest -- KiCAD 7 -- schematic and PCB-design program!!! You will certainly achieve far superior results using KiCAD than you ever will by using EasyEDA, although EasyEDA has its own fervent followers in this forum as well. In any case, one of the main reasons to go with KiCAD is because it is backed by the "CERN" group, which is who and what is behind "The Large Hadron Collider" project over there in Europe. It's because of this association that you have to know that a software program by an organization like "CERN" has -- GOTTA -- be right!!!

Here.....this will get you started. It's FREE!!!:

https://www.kicad.org/download/

[in this project you can make the modules any size you choose] -- I would suggest that you use whatever module width suits your project needs, while also using whatever connectivity I/O also suits your requirements. Meaning, if your module width needs to be 1.50" or 1.63".....so be it!!! Similarly, unless you desire to conform to some 500-Series or the newer 51x-Alliance standard electrically, I would go ahead and use whatever happens to suit your needs.

If you are able to provide me with a -- mechanical detail drawing/sketch -- of your module, I could then create a 3D CAD-model of your module, which would then allow you to better visualize all of what it is that you are working with. How many different modules like this are there going to be? (NOTE: Should you happen to have a STP/STEP file that you can send me, that would be GREAT!!! HINT: I am also a "Mechanical Designer" with a U.S. Patent for a 3U rack enclosure).



Send me whatever ya got, OK???

EDIT: Working from your highly-pixelated image shown above, I was able to eek out this 3D-Model of your panel. Of course.....having some actual dimensions of the panel itself would certainly help things along:

EDIT-2: Updated the fader mounting-holes and its slot dimensions:
(HINT, HINT, HINT: -- Having the actual "Front-Panel Designer" files would certainly HELP!!! - The Beatles):



/

 

[Brian Roth]

Very good advice! How about using the 500 format for the preamp/EQ/compression section and the EuroRack format for the fader section? Quite a few effects modules use the 500 format (Rupert NEVEs / SSLs or Maags) so people can build their own effects chains at will (kind of like SSL X Desk)

I see two problems all related to the fact a single 500 (or 51x) slot has only ONE input and output. Your proposed mic card has both mic and line inputs. A lesser issue is the insert send/return on the EQ card.

Then there is the entire issue that a complete system will require two totally different rack "frames".

Bri

 

[Brian Roth]

..we actually have our own revised standard here at groupdiy: The GroupDIY 51x Alliance

E.g. the 511 system: https://groupdiy.com/threads/the-official-groupdiy-511-help-support-thread.37438/

Yes, that is a good option for sure! The whole 500 type module concept for this project just came out of the clear blue last night! <g>

BTW, is there a compiled list of all available 51x modules? It may be buried in that 16 page discussion you linked....but I'm lazy, lol

Bri

 

[mmadu]

I see that you are using the "EasyEDA" program for your schematics. Here is something for you to think about when using the "EasyEDA" program that has recently come to light here on this GroupDIY forum.....-- apparently, there is a "glitch" within the "EasyEDA" software that causes connections in the schematic to -- NOT -- be connected within the PCB-design program!!! >> NOT GOOD!!! <<

One member of this forum just had some PCB's fabricated from GERBER files generated by "EasyEDA" only to discover several components as being -- NOT -- connected in the layout, although they were connected in his schematic. If only this member had known about - me - and had sent me his GERBER and N/C Drill data files first before having them fabricated, I could have processed his output files through my "GERBER File Analysis" program and its "DRC" routine would have picked-up this error beforehand!!! Just sayin'.....

Before you become too involved with your circuit design and schematic drawing, I would -- strongly suggest -- that you download and install the latest -- KiCAD 7 -- schematic and PCB-design program!!! You will certainly achieve far superior results using KiCAD than you ever will by using EasyEDA, although EasyEDA has its own fervent followers in this forum as well. In any case, one of the main reasons to go with KiCAD is because it is backed by the "CERN" group, which is who and what is behind "The Large Hadron Collider" project over there in Europe. It's because of this association that you have to know that a software program by an organization like "CERN" has -- GOTTA -- be right!!!

Here.....this will get you started. It's FREE!!!:

https://www.kicad.org/download/

[in this project you can make the modules any size you choose] -- I would suggest that you use whatever module width suits your project needs, while also using whatever connectivity I/O also suits your requirements. Meaning, if your module width needs to be 1.50" or 1.63".....so be it!!! Similarly, unless you desire to conform to some 500-Series or the newer 51x-Alliance standard electrically, I would go ahead and use whatever happens to suit your needs.

If you are able to provide me with a -- mechanical detail drawing/sketch -- of your module, I could then create a 3D CAD-model of your module, which would then allow you to better visualize all of what it is that you are working with. How many different modules like this are there going to be? (NOTE: Should you happen to have a STP/STEP file that you can send me, that would be GREAT!!! HINT: I am also a "Mechanical Designer" with a U.S. Patent for a 3U rack enclosure).

View attachment 122819

Send me whatever ya got, OK???

EDIT: Working from your highly-pixelated image shown above, I was able to eek out this 3D-Model of your panel. Of course.....having some actual dimensions of the panel itself would certainly help things along:

View attachment 122828

/

Good morning MidnightArrakis!

The reason why I use EasyEDA is its huge schematic library; and in China, EasyEDA's development company Shenzhen jlc has a very large industrial cluster. You can directly export the BOM file and purchase it on lcsc (just like mouser). You can also It is very convenient to place an order to manufacture the circuit board in EDA and send it to jlc. During the many years of our cooperation, jlc has never seemed to have a problem (by the way, EasyEDA also includes DRC testing).

But your reminder is a very good suggestion. Not everyone uses EasyEDA. Many people use KiCad or AD to design their drawings. Happily, I can export files in Altium Designer format (including schematics) and PCB) so that anyone can import them into their own EDA (I think KiCad also supports importing AD files) and modify and inspect them at will.

As for the 3D part, I'm someone who knows nothing about 3D modeling, so my panel modeling came from Front Panel Designer, so it was great to have someone so familiar with 3D modeling work on this project! Your joining will provide great convenience to the project! But as you can see we are still finalizing the specs on many parts, once the specs are finalized I will post the sizing and ask for your help!

 

[john12ax7]

A DIN style 32, 64, or 96 pin connector would give a lot of options. This has come up before, a universal standard would be nice, but not sure you can get everyone to agree what the pinout should be.

 

[mmadu]

I see two problems all related to the fact a single 500 (or 51x) slot has only ONE input and output. Your proposed mic card has both mic and line inputs. A lesser issue is the insert send/return on the EQ card.

Then there is the entire issue that a complete system will require two totally different rack "frames".

Bri

From what I've seen, the 500 series standard seems to include +4 and -2dB inputs which are just fine for mic and line inputs, while the 51x format only reserves one input, but this shouldn't be a problem. In fact, in most 500 series power boxes, both +4dB and -2dB seem to be wired together and through one input, and it seems we can switch both inputs via the M/L switch anyway, right? (such as HiZ switching of SSL VHD+)

As for the send/return, I think we could do this with an external hookup, perhaps between the preamp and EQ, with the switch placed on the fader board.

51x related information is attached

 

[mmadu]

A DIN style 32, 64, or 96 pin connector would give a lot of options. This has come up before, a universal standard would be nice, but not sure you can get everyone to agree what the pinout should be.

Yes, it's certainly easier to implement the link through a custom bus, but implementing a custom standard through this one project seems very difficult. One of the reasons why people use the 500 series standard is that there are quite a few manufacturers/individuals using this standard so that people can interchange things from different brands, and we lack such a large community team ,but if more people join. . . . . .

 

[mmadu]

..we actually have our own revised standard here at groupdiy: The GroupDIY 51x Alliance

E.g. the 511 system: https://groupdiy.com/threads/the-official-groupdiy-511-help-support-thread.37438/

By the way, since this project has become so big and plans to use the 51x standard, can we turn this into an official GDIY-led community thread? More people on board and a more standard process will make things a lot easier.

 

[Brian Roth]

From what I've seen, the 500 series standard seems to include +4 and -2dB inputs which are just fine for mic and line inputs, while the 51x format only reserves one input, but this shouldn't be a problem. In fact, in most 500 series power boxes, both +4dB and -2dB seem to be wired together and through one input, and it seems we can switch both inputs via the M/L switch anyway, right? (such as HiZ switching of SSL VHD+)

As for the send/return, I think we could do this with an external hookup, perhaps between the preamp and EQ, with the switch placed on the fader board.

51x related information is attached

Every 500 frame I've ever seen have EXACTLY one input XLR and one output XLR per 500 slot. There is no way to have a second input (or output or both) within the standard without using two slots per module.

Bri

 

[mmadu]

Every 500 frame I've ever seen have EXACTLY one input XLR and one output XLR per 500 slot. There is no way to have a second input (or output or both) within the standard without using two slots per module.

Bri

But different level inputs are indeed included in the standard 500 format (there is always a difference between standard and actual, such as thunderbolt 4 and usb4) Maybe in the connector, we can simply connect the two together and pass a single XLR connector and then switch it via a switch. I don't think anyone needs to connect the Mic and Line interfaces at the same time. If so, they can connect via a patch panel.

 

[Brian Roth]

But different level inputs are indeed included in the standard 500 format (there is always a difference between standard and actual, such as thunderbolt 4 and usb4) Maybe in the connector, we can simply connect the two together and pass a single XLR connector and then switch it via a switch. I don't think anyone needs to connect the Mic and Line interfaces at the same time. If so, they can connect via a patch panel.

Indeed, the ancient 15 pin connector format had the two different levels called out on the edge connector. I also agree a single input connector could be used for mic or line level (with a switch on the module to select).

However, the need to re-patch the input for mic or line level duties is not at all typical in a "mainstream" console design. In fact, many recording studio wiring systems (especially smaller studios vs. huge rooms with a Neve or SSL <g>) have no mic level patchbays. Mic level patchbays can be problematic.

I think I'm beating a dead horse,

Bri

 

[MidnightArrakis]

Good morning MidnightArrakis!

The reason why I use EasyEDA is its huge schematic library; and in China, EasyEDA's development company Shenzhen jlc has a very large industrial cluster. You can directly export the BOM file and purchase it on lcsc (just like mouser). You can also It is very convenient to place an order to manufacture the circuit board in EDA and send it to jlc. During the many years of our cooperation, jlc has never seemed to have a problem (by the way, EasyEDA also includes DRC testing).

But your reminder is a very good suggestion. Not everyone uses EasyEDA. Many people use KiCad or AD to design their drawings. Happily, I can export files in Altium Designer format (including schematics) and PCB) so that anyone can import them into their own EDA (I think KiCad also supports importing AD files) and modify and inspect them at will.

As for the 3D part, I'm someone who knows nothing about 3D modeling, so my panel modeling came from Front Panel Designer, so it was great to have someone so familiar with 3D modeling work on this project! Your joining will provide great convenience to the project! But as you can see we are still finalizing the specs on many parts, once the specs are finalized I will post the sizing and ask for your help!

[Many people use KiCad or AD to design their drawings] -- In addition to my primary PCB-design tool being the CADENCE/OrCAD "PCB Editor" program, I also have KiCAD and ALTIUM Designer installed on my CAD-workstation here-at-home as well.

[I can export files in Altium Designer format] -- When you get to the point where all of your audio circuitry is completely designed, then why don't you send me your finished design in the ALTIUM format, so I can look it over.

[my panel modeling came from Front Panel Designer] -- I also have "Front-Panel Designer" installed on my home CAD-workstation as well. Now that I know that, why don't you create a ZIP file containing all of your Front-Panel files and then I can directly obtain all of mechanical dimensions from your design-layouts firsthand!!!

And, directly related to some information within the "51X Specifications" PDF file that concerns me is.....this 51X spec. is calling out that the "Front-Panel width is 1.50-inches" and the "Front-Panel height is 5.25-inches". OK.....great!!! BUT!!! ..... Those dimensions are actually only "nominal" mechanical dimensions, just like in rack-panel mechanical dimensions.

The "nominal" 1U rack-panel height is -- 1.75" -- high. However, the -- ACTUAL -- mechanical height dimension is (usually) 1.72" high!!! A 2U rack-panel is "nominally" 3.50" high, but its -- ACTUAL -- mechanical height is 3.47" high. So.....based upon the basic rack-panel height criteria, a 500-Series module panel would have a "nominal" height of 5.25", while its -- ACTUAL -- mechanical height dimension would be 5.22". And, a 500-Series panel width would "nominally" be 1.50" wide, but its -- ACTUAL -- mechanical panel width would be 1.47" wide!!!

From what I have seen in a variety of 500-Series specification sheets, >> NOBODY << is calling this out or has ever properly documented any of this!!! And, again.....from what I have seen in this forum and other sites across the Internet, because none of this has been ever properly documented like the "EIA-310 D" rack-standards have, there is an abundance of confusion and "misinformation" about "what should be, should be"!!! Any thoughts on this???

[I will post the sizing and ask for your help!] -- I am "Standing By.....".....

/

 

[Brian Roth]

Since we are brainstorming here....

I've never worked with a Eurorack synth system, but have only read about it and seen pictures.

One thing just hit me like a ton of bricks. There is NO provisions for in/out connectors on the rear side of the rack. All I/O connections are via jacks on the front panels.

Just saying <g>.

Bri

 

[mmadu]

Since we are brainstorming here....

I've never worked with a Eurorack synth system, but have only read about it and seen pictures.

One thing just hit me like a ton of bricks. There is NO provisions for in/out connectors on the rear side of the rack. All I/O connections are via jacks on the front panels.

Just saying <g>.

Bri

Predictably however, while people seem to be willing to place some IO on the front panel (as is done on some PA mixers) preventing wiring on the EQ module front panel is not liked as that would Makes the whole panel cluttered (and gets in the way of the knobs).

I imagine that in a designed studio, the channels for mics and the channels for line/summing would be separated and labeled.

 

[mmadu]

[Many people use KiCad or AD to design their drawings] -- In addition to my primary PCB-design tool being the CADENCE/OrCAD "PCB Editor" program, I also have KiCAD and ALTIUM Designer installed on my CAD-workstation here-at-home as well.

[I can export files in Altium Designer format] -- When you get to the point where all of your audio circuitry is completely designed, then why don't you send me your finished design in the ALTIUM format, so I can look it over.

[my panel modeling came from Front Panel Designer] -- I also have "Front-Panel Designer" installed on my home CAD-workstation as well. Now that I know that, why don't you create a ZIP file containing all of your Front-Panel files and then I can directly obtain all of mechanical dimensions from your design-layouts firsthand!!!

And, directly related to some information within the "51X Specifications" PDF file that concerns me is.....this 51X spec. is calling out that the "Front-Panel width is 1.50-inches" and the "Front-Panel height is 5.25-inches". OK.....great!!! BUT!!! ..... Those dimensions are actually only "nominal" mechanical dimensions, just like in rack-panel mechanical dimensions.

The "nominal" 1U rack-panel height is -- 1.75" -- high. However, the -- ACTUAL -- mechanical height dimension is (usually) 1.72" high!!! A 2U rack-panel is "nominally" 3.50" high, but its -- ACTUAL -- mechanical height is 3.47" high. So.....based upon the basic rack-panel height criteria, a 500-Series module panel would have a "nominal" height of 5.25", while its -- ACTUAL -- mechanical height dimension would be 5.22". And, a 500-Series panel width would "nominally" be 1.50" wide, but its -- ACTUAL -- mechanical panel width would be 1.47" wide!!!

From what I have seen in a variety of 500-Series specification sheets, >> NOBODY << is calling this out or has ever properly documented any of this!!! And, again.....from what I have seen in this forum and other sites across the Internet, because none of this has been ever properly documented like the "EIA-310 D" rack-standards have, there is an abundance of confusion and "misinformation" about "what should be, should be"!!! Any thoughts on this???

[I will post the sizing and ask for your help!] -- I am "Standing By.....".....

/

By the way, you seem to be a professional PCB designer (at least more than me), would you be willing to draw the PCB for this project? (It’s a pity that there is no compensation, it is an open source project co-built, ha!)