I need to record 24 channels from the GL2400-424 to 24 analogue inputs of audio interface

Hi
Hello to everybody in this forum. Am new here.

I procured a used GL2400-424 mixer, thinking it would serve my purpose of home studio recording, where I need to record to a 24-channel audio interface from the mixer outputs. I now gather that only 22 Direct Outs are available on the 22 mono channels while channels 15 and 16 being stereo, do not have any direct outs. Instead there are two Mic Outs, and I haven’t really understood what the manual is trying to say about how to use those. My requirement is simple - how do I record from 24 channels? Someone suggested using the Left/Mono channels of 15 and 16 and sending to a group. Another person suggests sending to Matrix. It’s so very confusing.

Sorry if I am sounding a novice, but I really am in the area of such advanced analogue machines.

Any help or link would certainly help.

Thanks

If I understand you correctly, you want to connect exactly 24 sources with microphone levels to the 24 XLR jacks and send them to 24 jack jacks for recording?

If so: Do ​​the two sources on 15/16 need to be EQ’d and/or monitored before recording?

And if you need to monitor something, how do you do that?
What else is connected to the console via which jacks?
Speakers? Just headphones? Nothing at all?

I’ve looked at the documentation and assume the following:
You could also use the two XLR jacks 15 and 16 for microphone sources.
You could use the two MIC OUT jacks similarly to the other 22 DIRECT OUT jacks, but:
The two signals immediately after the gain are sent exclusively to the two MIC OUT jacks.
So you wouldn’t be able to use the EQs, monitor the two sources, or mix them with the other 22 signals in the console.
If that’s okay with you, you could try it that way.
If not, there are indeed other different possibilities and we have to look further …

Extremely sorry to have missed stating an important point.

I want to record not Mic level, but 24 line signals, going into the mixer as line level signals, out through Direct Outputs to 24 line level input channels of my audio interface. This will be done primarily for recording paas. Unless absolutely essential, I intend not to use EQ, Pan.

The problem is channels 15 and 16 being stereo, there are no direct outputs. So wondering if only the left channels of 15 and 16 can do the work by routing them through subgroup outputs.

So, you want to connect 24 line sources to 24 line inputs and send them as directly as possible to your audio interface via 24 direct outputs.?

Since you apparently don’t connect anything else to the console, I’m wondering why you don’t connect your 24 sources directly to the audio interface.?

Unfortunately, I don’t know what paas are.
I found something online from Korg, but they’re speaker systems, not audio sources. /

Again regarding the two missing channels:
I wouldn’t split the two sources into two channels, but would use either ST1 (unbalanced) or ST2 (balanced) in stereo.
Switch only (!) channel 15 to Group 1-2 using the button and set the channel fader and the group faders 1 and 2 to 0 dB.
The two signals should now be available at the group XLR outputs 1 and 2.

Make sure that the two securely mounted REV switches below the Aux 1 and 2 output controls are in the upper, standard position.

Otherwise, both group signals would be present at the 1/4" jack aux outputs, which could be advantageous depending on the cable configuration, but can also be very confusing.

Please don’t stone me if I’ve overlooked something - the console is a bit complex.

Also note that the DIRECT OUTS are pre-fader by default, but the previous owner may have internally converted them to post-fader via jumpers.

Sorry for typo. I meant PAN control.

About the Group outs I will have to review. Since the stereo channels 15 and 16 are mentioned as ST1 L/M and R and so on, the L/M would allow Mono signals, with nothing plugged into R channel.

That’s correct - at least as long as the corresponding contacts in the right-hand jack sockets are still working properly.

Agreed. I would only use one of those, so I stick to let’s say ST2 L/M and ST4 L/M, i.e. only the balanced Mono channels. I connect just one cable each, i.e. one balanced MONO cable to ST2 L/M and one balanced MONO cable to ST4 L/M. I leave out the Right Channels of both 15 and 16 unconnected. This should give me mono balanced signals. Hope I’m right.

I suppose you are speaking about stereo. However, I only need to send TWO MONO unpanned un-EQ’d signals, not stereo. Since all 22 mono channels have already been consumed, I will need the mono from the stereo channels. The issue was, how to get a Line Output from the two mono channels.

Agreed, provided I use both Channels 15 and 16 for Mono. There is a confusion about selecting the BAL knobs which say L-R and ODD/EVEN. I do not understand it. Again, there are PAN knobs for the GRPs. So how do I use these two separate knobs?

Yes.

That should work too.

Unfortunately, we still don’t know what your sources are.
Most of the people use keyboards or similar devices, which are often at least stereo.
That’s why I suggested you the stereo input, which can just as easily pass two independent mono signals.
I thought it could might be easier for you.

Set channel 15 to ODD (Group 1) and channel 16 to EVEN (Group 2).

This sets the group’s pan to LR.
(According to the manual, it should also be labeled TO LR.)
Since you’re not using LR, its position doesn’t matter.

Many thanks. That answers my queries.

About the sources - I am setting up a multi-computer synth based hybrid studio but based around analogue mixing and processing, not in the computer. Only the final stage of Mastering is planned on the computer.

Each synth computer (computer connected to multiple synths through audio interfaces) will record in its own PC, then manually transferred into a Main Synth computer. This Main Synth computer, in time sync with a Master Mac Mini M4 based computer with 24 channel audio interface, will send its tracks to the Master through the analogue mixer.

Your project sounds quite interesting, but it’s still not plausible to me.
I’d like to understand, but of course you don’t have to answer.

So far, I can’t see any evidence of this, because you’re just sending your 24 tracks through the mixer without any analog mixing or processing.
That was also the point where I asked why you don’t send the 24 tracks directly to the audio interface
Surely there are also at least gain controls there.

But mastering, as I understand it, means “tuning” a finished mix for a release.
But you now have 24 tracks on your computer…

Or was that just an intermediate step and you later convert your 24 digital tracks back to analog and send them through the mixer again - maybe only to convert them back AD to master them?

But that doesn’t sound like “everything analog - just mastering on the PC” at all.

I would understand the desire to try a purely analog mix, like in the old days, but why convert the signals back and forth so often…?
But maybe it doesn’t happen as often as I’m interpreting it to.

My opinion is that analog mixing or pure summing still played a major role a few years ago, but digital technology (hardware and algorithms) has also advanced significantly in this area as well.
But the main thing, of course, is that you enjoy doing it the way you want.
I’d be happy to read from you once more about it.

Why I Route Signals Through the Mixer During Tracking

You’re right that in my workflow, I’m not doing analog mixing or summing at the tracking stage. However, routing all signals through the analog mixer before they hit the interface serves several critical purposes beyond summing or EQ:

Preamplification & Analog Gain Staging

The mixer provides high-quality analog preamps for microphones and instruments. These are crucial to:

• Boost low-level mic signals to proper line level,
• Preserve headroom,
• Shape tonal character right at the front end.

Even if EQ and processing are bypassed, these preamps offer more analog warmth and headroom than many budget or mid-tier interface preamps.

Interfaces are often limited in channel count or lack sufficient quality preamps across all channels — the mixer fills that gap.

Yes, Interfaces Have Gain – But That’s Not the Whole Story

You’re absolutely right — most audio interfaces do offer basic gain controls. But here’s why I still route through the analog mixer instead of relying solely on interface gain:

Mixer Preamps Offer More Headroom and Better Sonic Control

Interface gain knobs often operate over a limited range and are designed for general-purpose use. In contrast:

• My analog mixer offers dedicated, full-range analog preamps with smoother gain curves,
• I get fine-tuned control over headroom, transient response, and saturation characteristics.

This matters especially when tracking dynamic sources like vocals, drums, or electric guitars, where how the preamp behaves shapes the tone.

Interfaces Typically Don’t Have Per-Channel Analog Routing

Yes, interface inputs have gain, but:

• They don’t provide insert points, subgroup routing, or monitoring sends per channel.
• With the mixer, I can route any input to outboard compressors, EQs, or headphone sends — all in real time, with zero latency and physical fader control.

Analog Consoles Handle Multiple Inputs More Fluidly

• My workflow involves tracking up to 24 channels simultaneously.
• Managing 24 preamps on a desktop interface or through software control panels is inefficient, especially when quick level adjustments or input swaps are needed.
• A mixer provides a unified control surface for all preamps — instantly accessible without opening software.

Monitoring Through the Mixer is Cleaner and Faster

• With the console, I can create custom monitoring mixes using Aux Sends, independent of what’s recorded.
• There’s no DAW latency, no digital round-trip monitoring, and no toggling between software panels.
• The performer hears exactly what they need — in real time — and I keep full control over tracking levels and tones.

Summary

Yes, the interface has gain — but the mixer gives me control, flexibility, and workflow efficiency that a standard interface alone simply can’t offer. It’s not just about volume — it’s about signal integrity, performer monitoring, analog headroom, and modular routing during a high-track-count hybrid session.

Routing Flexibility & Zero-Latency Monitoring

The mixer provides powerful routing and monitoring options, allowing me to:

• Create real-time monitor mixes without DAW latency,
• Blend click tracks, live mics, and backing stems,
• Feed multiple headphone amps with individualized cues,
• Switch monitoring paths instantly (pre/post EQ, aux sends, etc.).

This avoids relying on the DAW or interface mixer software, which can be restrictive or introduce latency.

Patchbay and Outboard Integration

The analog mixer forms the hub of my signal routing architecture:

• It allows me to patch in outboard compressors or EQs via inserts if needed,
• Normalize or reroute channels using hardware patchbays without touching the DAW or repatching cables behind the interface.

So even when no processing is applied, the mixer as a routing matrix ensures smooth reconfiguration during sessions.

Metering, Level Matching, and Hardware Monitoring

Analog consoles offer high-resolution peak metering per channel, which is critical during tracking:

• Ensures correct gain staging before the A/D converters,
• Prevents digital clipping at the interface stage,
• Allows visual monitoring of signal flow across all sources simultaneously.

Interfaces often lack physical metering per channel or are limited to simple LED ladders or software meters.

Recording Safety and Redundancy

The console acts as a buffer layer between source and interface:

• If a channel is faulty or overdriving, it’s easier to catch and reroute before hitting the DAW.
• I can record dry signals while still monitoring processed or EQ’d versions — great for making performer comfort mixes without committing those settings.

Workflow Consistency and Expandability

In a multi-machine, hybrid analog–digital studio, consistency matters. The console:

• Standardizes levels before signals hit any of my interfaces,
• Allows me to quickly redirect tracks between machines,
• Ensures the same monitoring chain is used whether I’m tracking, editing, or mixing.

In Summary

Even if I’m not actively “mixing” during tracking, the analog mixer is:

• My front-end for tone and gain control,
• My monitoring and routing center,
• My safety net for correct levels and redundancy.

So the signal doesn’t go through the console for summing, but it must go through it for capture precision, monitoring control, and system-level consistency — all of which are vital for clean, organized multi-track recording.

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Thank you for your very detailed answer, which, however, leaves me even more confused.
It reads as if I asked an AI that.

E.g. your …

… becomes now to …

But I have no further questions now and just wish you the best of luck with your project!

It does. My system is complicated, I use zai a lot.