SSR switching between input/output - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd November 2015, 02:08 PM   #1
Hdonly is offline Hdonly  United States
diyAudio Member
 
Hdonly's Avatar
 
Join Date: Oct 2015
Location: NW Florida
Default SSR switching between input/output

I was wondering about using solid state relays to switch between multiple inputs for passive preamps. Curious about distortion, bandwidth, and signal loss problems. Would ssr's work to keep the path short between in and out connectors. I am not up on these other than replacement for standard mechanical relays in motor control.
  Reply With Quote
Old 3rd November 2015, 02:31 PM   #2
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
The sort of solid state relay used in motor control is unlikely to be suitable for audio signals.

You can use JFETs (discrete, or package on a chip) to switch audio. Done properly I would expect them to be not much worse than a good mechanical switch.

Why do you want to keep the path short between in and out? This encourages stray capacitance coupling between them. Better to ensure that the distance is sufficiently long.
  Reply With Quote
Old 3rd November 2015, 02:57 PM   #3
Hdonly is offline Hdonly  United States
diyAudio Member
 
Hdonly's Avatar
 
Join Date: Oct 2015
Location: NW Florida
I wasn't suggesting that motor control ssrs would work, just that that is the kind I am familiar with. I have seen on Digikey that there are some designed for telecom use and was curious if anyone has experience with these types. Such as Vishay LH1518AAB. Very small and operate on low power. Just thought that keeping the wiring closer to the inputs would be better than running back and forth between the rear and front of an enclosure. I am a little new at this. That is why I am asking.
  Reply With Quote
Old 3rd November 2015, 03:58 PM   #4
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
I suspect that a motor control SSR and a telecom SSR use quite different devices (e.g. triac, JFET respectively) so the only thing they have in common (apart from the name) is that they both implement an electronically controlled switch.

Running wires back and forth inside an enclosure should not be a problem, provided that you use the right wire and get the grounding right. If the enclosure is metal and contains no power supply then you might not need to use screened/shielded cable for the internal wiring.
  Reply With Quote
Old 4th November 2015, 01:47 PM   #5
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
inserting a T pad of resistances can be used to tun on, or turn off an input.

Signal to top of upper jFET.
Series connect second jFET.
Connect a third jFET from junction to Signal Ground/Return.
Input tapped off the last jFET.

Turn top two jFETs to near zero ohms and bottom to near infinite ohms using control signals to the gates and the input passes to the output.
Swap the control signals, near infinite to top two and near zero to bottom and the input is blocked.

As many inputs as you want/need with groups of three jFETs. One set of control signal High/Low so that one set of jFETs passes signal and all other block signal.

You can probably buy those 3 jFETs in an IC package. It might be called a signal SSR.

The package might even include the conversion to the opposite phase control signal. One control signal generates the two turn ON and Turn OFF gate drive. and maybe an anti bounce circuit to prevent chattering.
__________________
regards Andrew T.
Sent from my desktop computer using a keyboard

Last edited by AndrewT; 4th November 2015 at 01:51 PM.
  Reply With Quote
Old 4th November 2015, 04:49 PM   #6
Hdonly is offline Hdonly  United States
diyAudio Member
 
Hdonly's Avatar
 
Join Date: Oct 2015
Location: NW Florida
Still kicking this can around. Thinking on momentary contact pushbutton on front panel with LEDs to show input. This SSR : Vishay VO1400AEF. with a logic stepping circuit to turn on/off SSRs. Maybe not a big advantage to mechanical switch, but it would be on the unique side. After all, it's just grownups playing with their toys
Attached Images
File Type: png Screenshot from 2015-11-04 10:39:55.png (224.5 KB, 163 views)
  Reply With Quote
Old 20th November 2015, 02:31 PM   #7
Hdonly is offline Hdonly  United States
diyAudio Member
 
Hdonly's Avatar
 
Join Date: Oct 2015
Location: NW Florida
Came up with a circuit to control the ssr switching with a single push button. Had help from someone that I came across on line. Didn't take him much longer than a blink to come up with this. He understands these IC's pretty darn good. I am going to build the board up and give it a try by itself and see how it works.
Attached Images
File Type: png Tony.png (22.8 KB, 137 views)
  Reply With Quote
Old 20th November 2015, 02:54 PM   #8
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
That Vishay chip is an interesting device...

Your 4017 can be elaborated upon to use a momentary button for each data line (meaning you can have a row of buttons on the front panel to select the required input). To do that needs another IC though such as a 4011.

If you buffer the outputs (so no current draw from the 4017) then you can add a simple capacitor backup supply (one cap, one diode) so that the last input selected is remembered. Actually, for your circuit that could be possible without buffering.

Here is another simple CMOS one... can't remember where this came from.
Attached Images
File Type: jpg Input Selector using 4028.JPG (66.3 KB, 139 views)
__________________
-------------------------------------------------------
Installing and using LTspice IV. From beginner to advanced.
  Reply With Quote
Old 20th November 2015, 02:59 PM   #9
Hdonly is offline Hdonly  United States
diyAudio Member
 
Hdonly's Avatar
 
Join Date: Oct 2015
Location: NW Florida
Was just thinking that this could be used to control relays also if that is what someone wanted to use. I plan on running an indicator LED to the front panel to show the active source input. I think this shows promise to eliminate one more place where audio signal goes through physical contacts.
  Reply With Quote
Old 20th November 2015, 03:04 PM   #10
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Yes it could drive relays. The 2N7000 FET is a great choice to interface CMOS logic to higher current loads.
__________________
-------------------------------------------------------
Installing and using LTspice IV. From beginner to advanced.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
3-way input audio input switching board (ebay) DWP Analog Line Level 8 16th January 2015 04:11 AM
does this make sense: SSR 1kHz switching regulator for PS rails? CharlieLaub Power Supplies 13 2nd October 2014 02:26 AM
SSR switching HT transformer? Matt BH Tubes / Valves 3 1st March 2013 10:50 PM
Input switching.. jethdub Parts 0 27th January 2008 09:19 PM
input switching svokke Solid State 5 3rd May 2003 04:58 PM


New To Site? Need Help?

All times are GMT. The time now is 12:57 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright 1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki