Hi,
I thought it's just a simple question. I need a volume controller (just 1 rotary knob) to control 8 line level outputs with this "just 1 knob".
Although, it seems not that simple, as I can only find 1500 euro costing commercial devices, with 8 inputs and 8 outputs AND this just 1 knob. OK< they added a mute and a dim function and a set of buttons to select input and output.
What I woud love to have is build my own device / volume knob with 8 inputs at line level connectors, controlled by that knob to get 8 output line level connectors. Dim and mute switch woud be fine, but not a must.
WHY??
I am having a home studio Hybrid mixing desk (48 channels mixing desk combined with a Mac mini and analog converters) to mix multitracks (studio recordings) as a hobby and now want to go for Dolby Atmos (5.1.2 format) so 8 analog line level signals to 8 powered loudspeakers (Genelec 3010A).
To be able to control the volume I need 1 knob on all 8 channels but have not found a rotary knob that hods 8 "layers" if you get what I try to put in words.
SOLUTIONS?
The whole world is watching as "boxes" exist from various brands, but they start at 1500 euro upwards to 6000 euro just to put the volume a bit higher or lower, which I find a bit " h^&^213n(&623H^$^& " (not so nice word)......
I thought it's just a simple question. I need a volume controller (just 1 rotary knob) to control 8 line level outputs with this "just 1 knob".
Although, it seems not that simple, as I can only find 1500 euro costing commercial devices, with 8 inputs and 8 outputs AND this just 1 knob. OK< they added a mute and a dim function and a set of buttons to select input and output.
What I woud love to have is build my own device / volume knob with 8 inputs at line level connectors, controlled by that knob to get 8 output line level connectors. Dim and mute switch woud be fine, but not a must.
WHY??
I am having a home studio Hybrid mixing desk (48 channels mixing desk combined with a Mac mini and analog converters) to mix multitracks (studio recordings) as a hobby and now want to go for Dolby Atmos (5.1.2 format) so 8 analog line level signals to 8 powered loudspeakers (Genelec 3010A).
To be able to control the volume I need 1 knob on all 8 channels but have not found a rotary knob that hods 8 "layers" if you get what I try to put in words.
SOLUTIONS?
The whole world is watching as "boxes" exist from various brands, but they start at 1500 euro upwards to 6000 euro just to put the volume a bit higher or lower, which I find a bit " h^&^213n(&623H^$^& " (not so nice word)......
Start here https://www.ti.com/audio-ic/amplifiers/volume-control-ics/products.html they are used in many pro applications.
Willem.
Willem.
Or, if it could be built, have that one knob to control 4 2-channel VCs, or 2 4-channel VCs, with gears? (Individual fine-tuning could become a challenge, though…
Another method would probably make use of a arduino or something, that would translate the master-knob’s position into 8 individual channels….
(Which would allow you to use any pot, as VC would be done in the backyard)
Another method would probably make use of a arduino or something, that would translate the master-knob’s position into 8 individual channels….
(Which would allow you to use any pot, as VC would be done in the backyard)
Hi Willem,
Thanks for the quick reply. Please remember I am NOT a technician to design a circuit in the professional way.
This potentiometer is a very simple solution, just the potentiometer between the output of the analog pre-amp (line level) and the input of the Active loudspeaker (line level). Would I need impedance matching before and after this potentiometer so both the pre-amp and the active loudspeaker "see" a fixed impedance? Also, I could add a switch connected to ground as a mute function for all signals (maybe best with a 8 gang relay to ground).
If this can work, I prefer this solution, as I only need volume control. Mute woud be fine and I can fix that.
Maybe even a "dim" function to a fixed lower signa level with a 8 gang relay and a fixed resistor per connection at the pre-amp side (so before the potentiometer). OR, After the potentiometer, to (variabel) dim the signal related to its original level (of the potentiometer) with a fixed amount of dB?
Cost would be low, easy to build, just some good soldering and a simple aluminium case.
Draw backs, unwanted effects / noise. ?????
-------
The PGA4311 looks like a good solution and a much more professional version but adds complexity, for me anyway.
I think it needs (at least):
- 2 of these IC's (daisy chained or how that is called, which it can I read in the doc) to get 8 channels of volume control
- a power board (+5V & -5V I read in the doc)
- Impedance matching not required or am I wrong here?
ISSUE: I don't understand what drives the circuit to control the volume. There is a IC test board, can that be used as PCB (if that is the right name). As it is a testing board it has a test function I don't need. Can it function without utilizing the test circuit?
It does have a "mute" function build in, which is good.
kind regards, Frans
how about 8 of these ladder volume control boards which already exists and you one arduino as the controller with one knob. Looking at about $400 USD, 8 boards at $50 each, for very high quality sound.
I could design the custom board of the controller. see:
https://www.diyaudio.com/community/threads/preamp-control-volume-input-mute-remote.326029/page-26
I could design the custom board of the controller. see:
https://www.diyaudio.com/community/threads/preamp-control-volume-input-mute-remote.326029/page-26
I would try 8 CDS cells (available at surplus houses) https://surplussales.com/Photovoltaic/pvc-1.html a tungsten light bulb, and a potentiometer to turn the light bulb from dark to bright. Plus a regulated power supply. TO make the volumes line up, you could insert different resistance in series with each CDS cell. <$100.
Yep, know that one. That's what I mean with more than 1000 Euro's for most of them of various brands to do this job. Only to control volume.....?
I hear those are very distorty, the simple 8-ganged pot from post #4 will trounce it for linearity, as well as being simple and cheap.
You might like to take a look at Rod Elliot's project 141 on the Elliot Sound Products (esp) website, https://sound-au.com/project141.htm . It is designed for multi-channel, based on the THAT2180 VCA and controlled by a single pot. He has a pcb available for it.
Hello,
This is my first ever writing on this forum
Might be i have simple solution for you, there is 6 gang motorized potentiometer from Alps. It's avaliable here https://www.conrad.hr/hr/p/alps-rk1...a-prasinu-stereo-0-05-w-10-k-1-st-442068.html
If you have 2 of them (20 euro each) and dual power opamp like L272 that costs very little, you can sacrifice 1 gang of each pot to be input voltage for opamp. I don't have exact schematic written but it's quite simple and basic diagram is in L272 data sheet.
When you manually turn one pot, opamp will turn other one until resistances of 2 sacrificed gangs are matched. I did it for 8 channel preamp and it works fantastic with only part of second delay for second pot (my hand is faster than motor).
This way you end with 10 gangs free for use.
Hope this helps
Drazen
This is my first ever writing on this forum
Might be i have simple solution for you, there is 6 gang motorized potentiometer from Alps. It's avaliable here https://www.conrad.hr/hr/p/alps-rk1...a-prasinu-stereo-0-05-w-10-k-1-st-442068.html
If you have 2 of them (20 euro each) and dual power opamp like L272 that costs very little, you can sacrifice 1 gang of each pot to be input voltage for opamp. I don't have exact schematic written but it's quite simple and basic diagram is in L272 data sheet.
When you manually turn one pot, opamp will turn other one until resistances of 2 sacrificed gangs are matched. I did it for 8 channel preamp and it works fantastic with only part of second delay for second pot (my hand is faster than motor).
This way you end with 10 gangs free for use.
Hope this helps
Drazen
Hi again, I found the diagram, its as simple as this. R1 and R2 are "sacrificed" gangs from 6 channel Alps pots (one from manually turned or master, second from slave). M1 is motor on slave pot. Solution will be some 40 Euro heavy... might be 50 with P&P. Gain matching is of course subject to Alps tolerances, which are not too bad as I measured under 10 % difference in resistance on different angles of the pot. That will translate in very few db differences.
I dont know where you live but at Thomann germany it costs 650 new and i see used ones for around 450.
"Only to control volume.....?“ Its a niche usage what you want and also Studio quality Volume is expensive.
Not many people want such things. So its an expensive hobby.
At least you know you buy it once and will probably have it forever
I think this is the best you will find as it does Exactly what you ask for. I am looking for one with 4 lines but this is the only decent one i have found till now. If i needed 8 channels like you i would have bought it already
Maybe 8 pieces "Dial Wheel Potentiometer"?
https://www.amazon.com/Wheel-Potentiometer-Stereo-Switch-Control/dp/B0B6FCGD6R
Or
4 pieces "72 Teeth Steel Pinion Gear 6mm Shaft Hole" mounting with dual gang potentiometers.
https://www.amazon.com/Wheel-Potentiometer-Stereo-Switch-Control/dp/B0B6FCGD6R
Or
4 pieces "72 Teeth Steel Pinion Gear 6mm Shaft Hole" mounting with dual gang potentiometers.
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