Dear all,
I am an electronic engineer with several years of experience in the industry. I've recently embarked on a new project aimed at creating a two-channel rotary mixer. In essence, this mixer will feature phono and line inputs, kill EQs, and a HP/LP filter. I have extensively studied the service manuals available on the web (such as RANE and A&H Xone), and I've gained a clear understanding of how to handle most aspects of this project. However, I have a question that remains unanswered: how should I manage the channel level?
In modern mixers, the mixing section typically incorporates a VCA (e.g., SSM2164) controlled by the crossfader and faders (in some cases, the VCA is solely controlled by the crossfader, while the channel faders are directly integrated into the analog path). This design is implemented to reduce the noise floor and increase tolerance to potentiometer wear. In a rotary mixer, there is no crossfader, which has led me to contemplate whether I should retain the VCA for channel level control or incorporate the faders directly into the signal path.
what´s your opinion?
I am an electronic engineer with several years of experience in the industry. I've recently embarked on a new project aimed at creating a two-channel rotary mixer. In essence, this mixer will feature phono and line inputs, kill EQs, and a HP/LP filter. I have extensively studied the service manuals available on the web (such as RANE and A&H Xone), and I've gained a clear understanding of how to handle most aspects of this project. However, I have a question that remains unanswered: how should I manage the channel level?
In modern mixers, the mixing section typically incorporates a VCA (e.g., SSM2164) controlled by the crossfader and faders (in some cases, the VCA is solely controlled by the crossfader, while the channel faders are directly integrated into the analog path). This design is implemented to reduce the noise floor and increase tolerance to potentiometer wear. In a rotary mixer, there is no crossfader, which has led me to contemplate whether I should retain the VCA for channel level control or incorporate the faders directly into the signal path.
what´s your opinion?
I'd optimize for low noise. If you're intending to use the mixer for DJing at night club SPLs you might want to ensure that potentiometer wear doesn't impact the sound as well. I suppose you don't want loud scratching noises as you fade between tracks. 🙂
Tom
Tom
I would go VCA without questioning myself: no need for expensive stereo audio ( log) faders or pots, relative imunity to wear, possibility to taylor response of fader/pot easily, possibility to use crossfader like Innovate audio xfaders, ease of replacement with lower cost parts ( linear mono)...
If you go that way // 2x 2164 ( by audio chanel) for lower noise floor it works well ( this strategy was used into SSL desks DBX 'gold can' vca) and leave enough headroom to accept pro line level signals ( +21/+24dbu) in signal path, it's one of the reason A&H mixers sounds goods ( they allow eq boost without turning the unit into a stompbox distortion generator).
Good idea about the overall design i will follow closely! Do you plan to integrate Riaa or make a line level unit edit: you answered? 2 chanels might be limiting, maybe 2 Riaa/line and two more line only chanel would be more inline with modern requirements ( less and less dj use 'real' TT).
If possible make it modular in spirit of old Midril, Eclerc or Freevox top of the line models, it's easier for troubleshooting.
If you go that way // 2x 2164 ( by audio chanel) for lower noise floor it works well ( this strategy was used into SSL desks DBX 'gold can' vca) and leave enough headroom to accept pro line level signals ( +21/+24dbu) in signal path, it's one of the reason A&H mixers sounds goods ( they allow eq boost without turning the unit into a stompbox distortion generator).
Good idea about the overall design i will follow closely! Do you plan to integrate Riaa or make a line level unit edit: you answered? 2 chanels might be limiting, maybe 2 Riaa/line and two more line only chanel would be more inline with modern requirements ( less and less dj use 'real' TT).
If possible make it modular in spirit of old Midril, Eclerc or Freevox top of the line models, it's easier for troubleshooting.
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Hi,
It's a dj mixer but with rotary control ( potentiometers) in place of linear faders.
Doesn't seems like a big deal but it change the way you mix.
An extreme example would be scratch/hip hop technique ( with fader) vs disco/techno/house technique ( with rotary knobs).
It's blurred line though as there is often option to include an external Xfader to rotary ( but you can't cut as fast as a fader for dedicated chanel control...). It's nice if you like smooth mixing technique, blend tracks for long period of times,...
It's a dj mixer but with rotary control ( potentiometers) in place of linear faders.
Doesn't seems like a big deal but it change the way you mix.
An extreme example would be scratch/hip hop technique ( with fader) vs disco/techno/house technique ( with rotary knobs).
It's blurred line though as there is often option to include an external Xfader to rotary ( but you can't cut as fast as a fader for dedicated chanel control...). It's nice if you like smooth mixing technique, blend tracks for long period of times,...
