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Stereo Sum Main an alternative to UIT?

Hi,

with the UIT being largely unobtainable (?) in kit form these days, and despite the footnote on the Stereo Sum page - https://www.st-modular.de/stereosum - saying "TO ENSURE THE MIXER'S FUNCTIONALITY, IT'S CRUCIAL TO HAVE AT LEAST ONE STEREO OR MONO CHANNEL, IN ADDITION TO YOUR MAIN MODULE", I would like to ask whether Sum Main could work as an alternative to UIT for the main purpose of the latter, i.e. an output module with headphone jack etc? I'm assuming the three stereo ins are unity gain added to the main mix even if there's no channel module connected; correct? Or or there any other showstoppers to be aware of?

Thanks in advance,

BR//Karl

...happy Honeyeater, EFI, Hapha, Cion, Yaze owner! :D

8 comments

Kommentare (8)

st-modular

Nov 27, 2023

Hello Karl,

Certainly, you can employ the Stereo Sum Main as an output module in conjunction with any Stereo Sum Mono or Stereo Channel module. However, it's worth noting that UIT offers a balanced output, which helps minimize noise and signal loss when using extended audio cables to connect to your PA, recording device, or external mixer—a feature not present in the Stereo Sum Main module. Nevertheless, I've effectively utilized it as the final module in my modular chain before connecting to my audio interface.

Best, Stefan

Karl @xoblite

Nov 27, 2023

Replying to

Thanks for the clarification Stefan; I am considering this option for a small compact rack where having the 3x stereo in would actually be quite useful in itself, never mind the headphone jack :)

Maybe later, say if it is moved to another rack, I would add some kind of channel module, but for now it's more like a "UIT+" kind of thing, minus the balanced outputs, that is, and being 8HP instead of 4HP. And, as noted, with the Sum Main still being available as a pre-soldered SMD full kit, for us middle-aged/lazy/impatient types ;)

Oh, btw, a semi-related designer's question: Have you tried the allegedly updated TL07xH for anything yet, and if so how do you find it compared to NE5532A and the like for audio specifically? (read: high level specs only tell half the story sometimes, and there's always the price/performance aspect to consider here of course, meaning fewer options available if you're working within a given parts budget with other heavyweights)

Thanks again,

BR//Karl

st-modular

Nov 28, 2023

Replying to

Why don´t you use the STM stereo Mixer instead? It offers three stereo inputs to be mixed to one output, ideal for small cases. I have not carried out a detailed analysis of the TL07xH and NE5532 ICs.

I think the advantages of the TL07XH version are marginal and not worth any further testing. The NE5532, with its transistor inputs, is recognized for outperforming the TL07X on the datasheet and is generally considered to be less noisy. However, the actual noise performance may depend on the source impedance. Although I used the NE5532 for microphone and headphone preamps, I couldn't find any significant advantages compared to the TLs, especially when you consider factors such as availability and price - these are elementary, especially for DIY projects.

Edited

Karl @xoblite

Nov 28, 2023

Replying to

Good point, I haven't really considered the STM. Another option would be for yours truly to get off his lazy #¤% and get that promising mixer design of his own ready for prototype manufacturing... ;) Thanks for the insights on the opamps; pretty much as I suspected. It seems implied from the datasheets that the TL07xH's are mostly about a refined process contributing to less fluctuations in performance (min/typ/max) from one part to the other. Whether to some extent this makes it more suitable for audio applications I guess is still an open question though.

BR//Karl