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YashN
Joined: Jun 27, 2011 Posts: 104 Location: Canada
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Posted: Thu Nov 24, 2011 12:09 am Post subject:
Best way to switch 8 lines at once Subject description: 8PDT are so rare! |
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I thought I had an easy mod to do on my hand: I need to be able to switch 8 lines simultaneously, so I initially thought of an 8PDT.
However, these are unobtainium... Rare, hard to find, mythical.
What's the best way to switch these 8 lines with a single switch? Should I go through two 4PDTs and a switch, or use relays and analog switches?
Schematics are most welcome. |
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a.b.o.z.
Joined: Feb 07, 2007 Posts: 351 Location: Zagreb, Croatia
Audio files: 7
G2 patch files: 4
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YashN
Joined: Jun 27, 2011 Posts: 104 Location: Canada
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Posted: Thu Nov 24, 2011 11:12 am Post subject:
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Thanks Ivan, looks like two good resources to study and go the analog switching way. I will check them out. |
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Tim Servo
Joined: Jul 16, 2006 Posts: 924 Location: Silicon Valley
Audio files: 11
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Posted: Sat Nov 26, 2011 10:57 pm Post subject:
Best way to switch 8 lines at once |
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Another chip you miight want to look at is the DG series high voltage analog switches. The 4016 and 4066 are limited to +/-7.5V signals (less if the supply voltages are lower than +/-15V), where the DG411 will switch signals all the way up to the power supplies (in other words, they'll switch a +/-15V signal if powered by +/-15V supplies). They're a little more expensive than the 4016/4066 (about $2.50) but they offer very good performance for the price. They're also available in NC (411), NO (412), and mixed (2 NC and 2 NO in the DG413).
Tim (switched at birth) Servo |
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YashN
Joined: Jun 27, 2011 Posts: 104 Location: Canada
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Posted: Sun Nov 27, 2011 12:28 am Post subject:
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Hey Tim, what a coincidence, I was just reading some of your posts on the synth-diy archives tonight (or was it the SQ-80 one?).
Thanks for the additional pointers, I will look at these too.
Up to now, I think I will need to have one physical switch which will control 2 analog switches, each responsible for a set of 4 lines. Did I get this right?
I would like to get to the point where I feel confident and I have a clear schematic and also a clear BOM so that I can send an order to Newark, Digikey or Mouser but I think I'm not there yet as I still need to read Ivan's linked articles. |
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ickystay
Joined: Nov 15, 2006 Posts: 142 Location: Oregon
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YashN
Joined: Jun 27, 2011 Posts: 104 Location: Canada
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Posted: Tue Dec 06, 2011 11:42 pm Post subject:
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Good point, ickystay. Need to see if thrift stores here have these kinds of things. Actually, now that I think of it, Addison, which is a surplus electronics store probably had some of these multi-pole rotary switches.
Here is another similar one I found:
From here: http://www.maaki.com/thomas/sas/jupiter4/jp4_cv/ |
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ericcoleridge
Joined: Jan 16, 2007 Posts: 889 Location: NYC
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Posted: Wed Dec 07, 2011 12:31 pm Post subject:
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here's a great schematic of 4016 4-pole switching from Juesrgen Haible's Polymoog Resonator. |
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YashN
Joined: Jun 27, 2011 Posts: 104 Location: Canada
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Posted: Sun Jan 01, 2012 3:26 pm Post subject:
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Thanks, Eric, looks interesting too. |
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remork
Joined: Aug 02, 2009 Posts: 25 Location: bhellgium
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YashN
Joined: Jun 27, 2011 Posts: 104 Location: Canada
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Posted: Wed Jan 04, 2012 1:41 am Post subject:
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Those wouldn't do at all. |
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remork
Joined: Aug 02, 2009 Posts: 25 Location: bhellgium
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Posted: Wed Jan 04, 2012 7:15 am Post subject:
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lol
i used one of those (with only two buttons) to switch between 2 modes on a modified casio keyboard.
together they're an 8PDT, since each button contains 4 SPDTs, and they're mechanically linked.
but i see how it wouldn't work, space- or layout wise. |
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remork
Joined: Aug 02, 2009 Posts: 25 Location: bhellgium
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Dave Kendall
Joined: May 26, 2007 Posts: 421 Location: England
Audio files: 3
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Posted: Wed Jan 04, 2012 8:41 am Post subject:
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Hi all.
An advantage of the 4053 and 4051, is that switching ±5V peak to peak voltages centred on GND is possible if pin 8 (VSS) is connected to GND, pin 7(VEE) connected to -5V, and pin 16 (VDD) connected to +5V.
Logic levels of GND to +5V will switch the I/O in this mode. Using ±7.5 or ±8V suplies will give some more headroom.
For DC only (0V to +10V) tie pins 7+8 to GND and connect pin 16 to +15V. A logic level high of around 10V or more is needed in this mode to switch the I/O.
Some brands of 4051/3 can handle larger voltage swings - Toshiba TC4051BP are rated for max 20V between VEE and VDD in the first mode, though it may be pushing it a bit too hard to expect to switch ±10V........
Interestingly, 74HC4051/4053 can also handle ±6V peak to peak voltages, with supplies of -6V, GND and +6V, again with a 0V to +5V logic level switch, whereas most normal 74HC types can only handle 0V to +6V. The advantage of 74HC types is typically a lower resistance across the switch than regular CMOS, and faster switching times.
cheers,
Dave _________________ "Everything in moderation, including moderation" |
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remork
Joined: Aug 02, 2009 Posts: 25 Location: bhellgium
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Posted: Wed Jan 04, 2012 9:42 am Post subject:
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hey, thanks dave! that's new and useful info to me there.. |
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YashN
Joined: Jun 27, 2011 Posts: 104 Location: Canada
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Posted: Wed Feb 12, 2014 5:54 pm Post subject:
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Very cool info both of you. Thanks for sharing. |
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