Compact desktop line mixer?

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The X-Desk is an absolutely great desk, especially when considering all of the routing options and price point. I mixed this entire project on an X-Desk that I borrowed while I was working on modding my Scorpion:



The only thing that I could not use was the talkback. When you pressed the button, the loud click in headphones rattled your brain, so I had to use a separate mic to talk to performers. But for everything else, I would strongly recommend one if building a mixing setup with limited budget.

It would be awesome to have a DIY version of this size that handled mixing duties. You could even include a discrete transformer based summing bus option. Metal work wouldn't be terrible. A folded top cover and a bottom with sides folded up. Make it a little bigger to use 100mm faders.

I also do not enjoy metal work. Mostly because want I want it to look like and what it actually does look like are very different things.

Thanks!

Paul
 
That sounds great, and yes, the X-Desk does seem very close to what I'm looking for. Used prices are still fairly high though.

It would be really cool to have a DIY option with similar functionality and a similar compact layout, in a modular setup (and maybe a nicer mix bus). Speaking of functionality, it can probably be simplified further from my initial post. I guess we really don't need an input trim, since we're just feeding pots/faders to set gain anyway. I also agree that HPF can be done in the box. Considering that, here's a basic schematic of an "input channel." I could be swayed to go with either the "Cheap version" or the "Fancy version." If going the cheap route, U3 could be an IC opamp as well, and the rails could be +/- 16V instead of 24V.

Screenshot 2025-01-12 at 2.09.40 PM.png
 
Metal work wouldn't be terrible. A folded top cover and a bottom with sides folded up. Make it a little bigger to use 100mm faders.

I also do not enjoy metal work. Mostly because want I want it to look like and what it actually does look like are very different things.
>> Your mix sounds terrific and her music is also emotionally touching as well. NICE CONCERT!!! -- Makes me wish that I was younger again when I used to mix and record concerts. I really do miss being a part of all of that activity way back then!!!

>> Here's a little something that I had recorded back around 1973 with basically "NO" equipment that in a rather broad sense is "somewhat similar" to Shannon's style of music!!! I built the microphone mixer from a kit that was available at the time and the mixed audio was recorded onto a CROWN "SX-722" reel-to-reel tape-recorder:

https://app.box.com/s/katttpc90byxtkvcovc38a896h467s40

>> Here's something else that I had recorded back in 1978 that was also simulcast on a local FM-station (and, by "local" I mean to where the venue was located and not where I lived, as I lived in the next state over west from where this concert took place). This was a "nightmare" situation, as the simulcast mixing console was located in the -- BASEMENT -- of the concert venue with NO visual stage monitors or anything!!! I had to "guess" who was singing and doing solo's in order to ride the faders. Back then, we didn't have readily available compressors, video cameras and monitors or much of anything. So, what you hear here is just me "winging it" while mixing to an audience of over 100,000+ FM-radio listeners in 2 countries!!! PRESSURE MUCH???..... This was also recorded onto my CROWN "SX-722" tape-recorder and the signal was from an FM-tuner that I had taken along with me. I had a choice of either taking a "Direct Out" from the mixing-console or a "Line-Out" from the FM-tuner. I chose the FM-tuner audio because I thought at-the-time that having the radio-station audio included would be pretty neat. In hindsight, however, I have regretted doing things this way because -- ANYBODY -- could have recorded this concert off-the-radio and say that "they had mixed it". On the other hand, essentially -- ONLY -- the person who HAD mixed the show and had recorded it directly from the mixing-console itself could actually say that they had mixed it and also have the tapes to prove it. So.....there's that!!!.....

https://app.box.com/s/irt04zmy4bh8trkhaljlnhq5obv31obn

[I also do not enjoy metal work. Mostly because want I want it to look like and what it actually does look like are very different things] -- NO BIGGIE!!! Just sketch out what you would like to have and maybe I could design all of the metal-work for you as you -- WANT -- it to be!!! That's what I do now. (See attached PDF file).

Here's a beginning of something that I am currently messing around with now. This is all rather bare and raw because I have JUST started to work on this and figure everything out:

1736718288027.png

>> In addition, go back to my Post #78 in this thread to view my sheet-metal "Reverse-Engineering" of a 200B channel-strip:

https://groupdiy.com/threads/compact-desktop-line-mixer.89576/post-1184097

/
 

Attachments

  • JBW-Designed - Rack Assemblies Design Portfolio & DAB Chassis.pdf
    9 MB
That sounds great, and yes, the X-Desk does seem very close to what I'm looking for. Used prices are still fairly high though.

It would be really cool to have a DIY option with similar functionality and a similar compact layout, in a modular setup (and maybe a nicer mix bus). Speaking of functionality, it can probably be simplified further from my initial post. I guess we really don't need an input trim, since we're just feeding pots/faders to set gain anyway. I also agree that HPF can be done in the box. Considering that, here's a basic schematic of an "input channel." I could be swayed to go with either the "Cheap version" or the "Fancy version." If going the cheap route, U3 could be an IC opamp as well, and the rails could be +/- 16V instead of 24V.

View attachment 143249
I am currently using AM10 style op amps in my TAC scorpion which are line level only and use no transformers for the balanced input. It was a project from Eli Audio a while back. We could do something along those lines and then use transformers for the master fader and output. 2-4 aux sends and some stereo returns and this might be a very cool project that could fit in about an X-Desk sized footprint.

Although going the IC route makes a little more sense. If you wanted fancy you could use TLE2072 for the unbalancing/routing. I think the biggest difference will be a great sounding circuit with quality transformers in the mix bus section.

Thanks!

Paul
 
That sounds great, and yes, the X-Desk does seem very close to what I'm looking for. Used prices are still fairly high though.

It would be really cool to have a DIY option with similar functionality and a similar compact layout, in a modular setup (and maybe a nicer mix bus). Speaking of functionality, it can probably be simplified further from my initial post. I guess we really don't need an input trim, since we're just feeding pots/faders to set gain anyway. I also agree that HPF can be done in the box. Considering that, here's a basic schematic of an "input channel." I could be swayed to go with either the "Cheap version" or the "Fancy version." If going the cheap route, U3 could be an IC opamp as well, and the rails could be +/- 16V instead of 24V.

View attachment 143249
Looking good! Here are a few comments.

1. I attached a RothCAD <g> scribble of the basics for an alternate input stage. I found the idea decades ago in Jung's Opamp Cookbook and have used it many times since. Easy gain tweakability. Back Then we didn't have the nice THAT chips, so a common dual opamp worked well.

2. FWIW, I prefer the dual gang pan pot circuit vs. the single gang with wiper grounded. Years ago, an article in (maybe?) R/EP by (maybe?) Paul Buff discussed how to optimally tweak the single gang version.

3. Speaking of pan pots, the R values of the one hanging from the Aux 3 level pot will load down the wiper and affect the taper of the level pot.

4, Just an random idea for the pre/post Aux switches....maybe a center-off switch for muting that aux?

5. Maybe same idea for the PFL switch: AFL/off/PFL.

6. If the "Mix Bus" switch is replaced by relay contacts, it could provide both muting and solo-in-place.

I may be over-thinking this!

"A camel is a horse designed by a committee."

Bri
 

Attachments

  • Bal Input with Trim.pdf
    18.5 KB
>> Your mix sounds terrific and her music is also emotionally touching as well. NICE CONCERT!!! -- Makes me wish that I was younger again when I used to mix and record concerts. I really do miss being a part of all of that activity way back then!!!

>> Here's a little something that I had recorded back around 1973 with basically "NO" equipment that in a rather broad sense is "somewhat similar" to Shannon's style of music!!! I built the microphone mixer from a kit that was available at the time and the mixed audio was recorded onto a CROWN "SX-722" reel-to-reel tape-recorder:

https://app.box.com/s/katttpc90byxtkvcovc38a896h467s40

>> Here's something else that I had recorded back in 1978 that was also simulcast on a local FM-station (and, by "local" I mean to where the venue was located and not where I lived, as I lived in the next state over west from where this concert took place). This was a "nightmare" situation, as the simulcast mixing console was located in the -- BASEMENT -- of the concert venue with NO visual stage monitors or anything!!! I had to "guess" who was singing and doing solo's in order to ride the faders. Back then, we didn't have readily available compressors, video cameras and monitors or much of anything. So, what you hear here is just me "winging it" while mixing to an audience of over 100,000+ FM-radio listeners in 2 countries!!! PRESSURE MUCH???..... This was also recorded onto my CROWN "SX-722" tape-recorder and the signal was from an FM-tuner that I had taken along with me. I had a choice of either taking a "Direct Out" from the mixing-console or a "Line-Out" from the FM-tuner. I chose the FM-tuner audio because I thought at-the-time that having the radio-station audio included would be pretty neat. In hindsight, however, I have regretted doing things this way because -- ANYBODY -- could have recorded this concert off-the-radio and say that "they had mixed it". On the other hand, essentially -- ONLY -- the person who HAD mixed the show and had recorded it directly from the mixing-console itself could actually say that they had mixed it and also have the tapes to prove it. So.....there's that!!!.....

https://app.box.com/s/irt04zmy4bh8trkhaljlnhq5obv31obn

[I also do not enjoy metal work. Mostly because want I want it to look like and what it actually does look like are very different things] -- NO BIGGIE!!! Just sketch out what you would like to have and maybe I could design all of the metal-work for you as you -- WANT -- it to be!!! That's what I do now. (See attached PDF file).

Here's a beginning of something that I am currently messing around with now. This is all rather bare and raw because I have JUST started to work on this and figure everything out:

View attachment 143254

>> In addition, go back to my Post #78 in this thread to view my sheet-metal "Reverse-Engineering" of a 200B channel-strip:

https://groupdiy.com/threads/compact-desktop-line-mixer.89576/post-1184097

/
I suggest you should do a full metal work design that are about the same dimensions of the X-Desk with corresponding PCBs, present your work here on this thread and ask for input/suggestions on feature set, and then offer a group buy for boards and chassis. Or you can just order the all the parts and then setup a White Market account and sell them there. If you are going to be offering your services as available for hire you need to post them in the Available for Hire section of this forum.

Thanks!

Paul
 
That sounds great, and yes, the X-Desk does seem very close to what I'm looking for. Used prices are still fairly high though.

It would be really cool to have a DIY option with similar functionality and a similar compact layout, in a modular setup (and maybe a nicer mix bus). Speaking of functionality, it can probably be simplified further from my initial post. I guess we really don't need an input trim, since we're just feeding pots/faders to set gain anyway. I also agree that HPF can be done in the box. Considering that, here's a basic schematic of an "input channel." I could be swayed to go with either the "Cheap version" or the "Fancy version." If going the cheap route, U3 could be an IC opamp as well, and the rails could be +/- 16V instead of 24V.

View attachment 143249

What are the perceived benefits of the "Fancy Version" ?
 
I suggest you should do a full metal work design that are about the same dimensions of the X-Desk with corresponding PCBs, present your work here on this thread and ask for input/suggestions on feature set, and then offer a group buy for boards and chassis. Or you can just order the all the parts and then setup a White Market account and sell them there. If you are going to be offering your services as available for hire you need to post them in the Available for Hire section of this forum.

Thanks!

Paul
To the best of my knowledge, @MidnightArrakis is retired and has always offered his services for free.

Cheers

Ian
 
>> Your mix sounds terrific and her music is also emotionally touching as well. NICE CONCERT!!! -- Makes me wish that I was younger again when I used to mix and record concerts. I really do miss being a part of all of that activity way back then!!!

>> Here's a little something that I had recorded back around 1973 with basically "NO" equipment that in a rather broad sense is "somewhat similar" to Shannon's style of music!!! I built the microphone mixer from a kit that was available at the time and the mixed audio was recorded onto a CROWN "SX-722" reel-to-reel tape-recorder:

https://app.box.com/s/katttpc90byxtkvcovc38a896h467s40

>> Here's something else that I had recorded back in 1978 that was also simulcast on a local FM-station (and, by "local" I mean to where the venue was located and not where I lived, as I lived in the next state over west from where this concert took place). This was a "nightmare" situation, as the simulcast mixing console was located in the -- BASEMENT -- of the concert venue with NO visual stage monitors or anything!!! I had to "guess" who was singing and doing solo's in order to ride the faders. Back then, we didn't have readily available compressors, video cameras and monitors or much of anything. So, what you hear here is just me "winging it" while mixing to an audience of over 100,000+ FM-radio listeners in 2 countries!!! PRESSURE MUCH???..... This was also recorded onto my CROWN "SX-722" tape-recorder and the signal was from an FM-tuner that I had taken along with me. I had a choice of either taking a "Direct Out" from the mixing-console or a "Line-Out" from the FM-tuner. I chose the FM-tuner audio because I thought at-the-time that having the radio-station audio included would be pretty neat. In hindsight, however, I have regretted doing things this way because -- ANYBODY -- could have recorded this concert off-the-radio and say that "they had mixed it". On the other hand, essentially -- ONLY -- the person who HAD mixed the show and had recorded it directly from the mixing-console itself could actually say that they had mixed it and also have the tapes to prove it. So.....there's that!!!.....

https://app.box.com/s/irt04zmy4bh8trkhaljlnhq5obv31obn

[I also do not enjoy metal work. Mostly because want I want it to look like and what it actually does look like are very different things] -- NO BIGGIE!!! Just sketch out what you would like to have and maybe I could design all of the metal-work for you as you -- WANT -- it to be!!! That's what I do now. (See attached PDF file).

Here's a beginning of something that I am currently messing around with now. This is all rather bare and raw because I have JUST started to work on this and figure everything out:

View attachment 143254

>> In addition, go back to my Post #78 in this thread to view my sheet-metal "Reverse-Engineering" of a 200B channel-strip:

https://groupdiy.com/threads/compact-desktop-line-mixer.89576/post-1184097

/
I would build this enclosure, supply all materials minus the meters,and ship it for free just to see this project completed. If you design it.
 
What are the perceived benefits of the "Fancy Version" ?
Higher headroom, theoretically better CMMR, street cred. In use…probably not too much. I agree with @Potato Cakes that the DOA’s and transformers are probably best left to the summing and output amps.

@Brian Roth good feedback! I like the THAT input, and it’s cheap enough and high-performance enough that it seems like it’s worth using. We could easily use 5534’s elsewhere. I’ll have to dig into the pan pot circuit. My goal was to avoid hard-to-find, and often poorly-matched dual gang pots.

@MidnightArrakis LED meters are cheaper, smaller, and easier to drive :)

Also, for reference, the X-Desk is 19” wide and 12.25” deep, which makes it perfect for both desktop use and rack-mounting for those who like rack-mounted mixers.
 
X-Desk: Wow, three grand used, for that little guy (not including whatever D-Sub fanouts one would need)!

One could DIY a helluva mixer for that amount of money.
 
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@Brian Roth good feedback! I like the THAT input, and it’s cheap enough and high-performance enough that it seems like it’s worth using. We could easily use 5534’s elsewhere. I’ll have to dig into the pan pot circuit. My goal was to avoid hard-to-find, and often poorly-matched dual gang pots.

My only reason for suggesting the Walt Jung balanced input design was the ease of adding a trim control and the lower price of a dual opamp vs. a THAT chip. Call me Budget Brian! lol The audio performance is excellent.

The dual gang pan pot design is regularly used in just about every pro desk ever made. It has a bit lower signal loss, easy to establish the "how many dB at center". It uses a dual gang LINEAR pot so section tracking isn't a big deal. Downside.....more space behind the front panel (and violating Budget Brian's approach it is more expensive).

Bri
 
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