• lgp
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Topic: Add a second Fireface 800?

I am looking into a solution where I can add more inputs and outputs to my existing Fireface 800 connected to a MacBook Air M2. I have read some information here in the forums and also watched RMEs videos on how to connect two FF800s. I also use the chain of adapters to connect my current FF 800 to my Mac.

Anyone tried to add a second FF 800 to get more inputs and outputs when connected with adapters to a Mac? Are the solution stable?

2 Reply by ramses (edited by ramses 2026-07-07 22:10:22)

  • ramses
  • ramses
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Re: Add a second Fireface 800?

Hi lgp.

Welcome to the RME user forum.

I am not using Mac. But as far as I understood, there are two connection methods possible:
Daisy Chaining and Aggregate Devices.

While FireWire allows physical daisy-chaining, on Apple Silicon with adapters, the Mac will see them as two distinct CoreAudio devices. To use them together, you would have to create an Aggregate Device in macOS Audio MIDI Setup.
I read that this is historically notoriously unstable with FireWire-to-Thunderbolt adapter chains.

Both methods have one drawback: you need to route through the DAW with higher latency,
depending on buffer settings, when routing audio from an input of FF800#1 to an output of FF800#2.

Depending on your use cases, direct routing on one interface is preferable.
E.g., if a vocalist sings to a backing track for latency-free monitoring through headphones.

3rd possibility: the ADAT Expansion Method (best current solution instead of daisy chaining or aggregate device)
You could achieve this by using one FF800 as the main interface and connecting the 2nd FF800 through ADAT.
Either in stand-alone mode or connected through FireWire to be able to operate it.
By this you can perform latency-free direct routing without having to route through FireWire or the DAW.

BTW, I read that FireWire support has been ceased by Apple in the latest versions of macOS.

4th possibility - upgrading the main interface (the best long-term solution):
Get one USB or PCIe-based recording interface with the needed port capacity
and connect preamps and/or AD/DA converters to it.

BR Ramses - HDSPe MADI FX, M-1620 Pro D, 12Mic, UFX III, ADI-2 Pro FS R BE, Nuendo 15, Win10 IoT Ent

3 Reply by waedi (edited by waedi 2026-07-08 00:04:22)

  • waedi
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Re: Add a second Fireface 800?

Use 1 FF800 as interface connected with the adapters
Use the second FF800 in standalone-mode as ADDA converter connected with toslink cables to the first FF800.
This gives you additional analog inputs and outputs to the first FF800, as you requested.

You have to stay on an old MacOS not allowed to upgrade to MacOS Tahoe with the FF800 in use.

My recommendation, get rid of the FF800s and upgrade the computer to the latest OS.
For 32 analog inputs and outputs, cheap solution : RME Digiface USB plus 4 x Behringer ADA8200 = ca 1060 Euro

More I/Os, more expensive : RME UFX lll plus some converters from RME or Ferrofish

To your question if it is stable, no, it is not stable because these adapters you have to use for firewire connection, are prone to burn out at long time usage, these Apple adapters are expensive sold but very cheap made. Not reliable, not stable.

M1-Tahoe, Madiface Pro, Digiface USB, Babyface silver and blue
  • Apfel
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Re: Add a second Fireface 800?

waedi wrote:

… To your question if it is stable, no, it is not stable because these adapters you have to use for firewire connection, are prone to burn out at long time usage, these Apple adapters are expensive sold but very cheap made. Not reliable, not stable.

I have been using this connection with the original Apple adapters for many years now (+6 years?). They are still the first and only set of adapters and have never been changed. No problems and instabilities at all over the years and still now.

iMac M1 16GB, Fireface 800, Logic Pro X
  • waedi
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Re: Add a second Fireface 800?

Apfel wrote:

I have been using this connection with the original Apple adapters for many years now (+6 years?). They are still the first and only set of adapters and have never been changed. No problems and instabilities at all over the years and still now.

More power to you, thats great, let's hope they last for long.

M1-Tahoe, Madiface Pro, Digiface USB, Babyface silver and blue
  • From: Germany
  • Registered: 2025-02-06
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Re: Add a second Fireface 800?

maybe just use a digiface usb. With 2x ADAT in/out to both devices you'll have a lot of channels at disposal and can route between the FF800 within the digiface mixer for low latency

UCX II, BBF Pro FS, Quadmic II, PCIe HDSPe Multiface II, AIO Pro
  • Registered: 2018-12-21
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Re: Add a second Fireface 800?

If they work fine for you, I would keep the FF800s connecting one via ADAT to the other one. For all channels you might wanna use ADAT 1 and 2.
Once you need to update past macOS Sequoia get another interface depending on needs and budget (digiface usb is cost effective option, if you need more features look into UFX III). I would keep using FF800s in standalone then, just make sure to set them up in a useful way beforehand (e,g, leaving phantom on if needed, as this cannot be controlled in standalone).

I can’t say these adapters break easily. We are using many FF800s here in a shared user environment over many years. I had more failures of FireWire cables over the years than those adapters.

Also never had a problem with daisy chaining, but make sure to connect to the Mac to the FireWire 800 port (not to the 400 port).