Simultaneous relay switching ?

[tubenit]

Anyone have a schematic drawing of how to switch two DPDT relays with ONE footswitch  (in contrast to one foot switch box with two footswitches in it).

In other words, one switch will operate two relay DPDT's simultaneously.

I have some ideas on this but thought maybe someone has done this before?

With respect, Tubenit

[sluckey]

Just wire the relay coils in parallel.

[John]

I think Geezer's HoSo had those, didn't it?

[PRR]

If you can bring all the switching together, 4P2T relays exist.

Generally: what Slucky said.

[EL34]

Yes, what they said plus this diagram
This diagram shows LED indicators which you can ignore

[Geezer]

I think Geezer's HoSo had those, didn't it?

Yes....I use Weber's 4x relay board. In fact, I just wired one up in my DuMars OD Preamp. Very simple to do the multi-switching, any combo possible.

.G

[tubenit]

Gentleman,

THANKS for the responses! I appreciate them.

I am currently using a relay that has an isolated jack essentially using a spdt for clean/OD.  

I am thinking that I'd switch to a stereo jack IF I was wanting to use two foot switches with two DPDT relays using the second DPDT for a mid boost (and maybe something else with it) ?  This would have the DPDT's switch independently of each other.

However, if I was switching both DPDT's simultaneously than (per Hoffman's schematic) than one foot switch would accomplish that?

Am I headed the right direction thinking about this?

with respect, Tubenit

[sluckey]

I am thinking that I'd switch to a stereo jack IF I was wanting to use two foot switches with two DPDT relays using the second DPDT for a mid boost (and maybe something else with it) ?  This would have the DPDT's switch independently of each other.

That's correct. And using two SPST footswitches to control the two relays independant  of each other gives you more flexibility/options.

However, if I was switching both DPDT's simultaneously than (per Hoffman's schematic) than one foot switch would accomplish that?

In this case, connect both relay coils together (in parallel) and use one SPST footswitch to energize both relays simultaneously. Just think of the two DPDT relays as one 4PDT relay. And don't let the number of contacts in the relay confuse your thinking. All you need to think about is the coil connections. All you want to do at this point is make the relays click.

[tubenit]

In this case, connect both relay coils together (in parallel) and use one SPST footswitch to energize both relays simultaneously. Just think of the two DPDT relays as one 4PDT relay. And don't let the number of contacts in the relay confuse your thinking. All you need to think about is the coil connections. All you want to do at this point is make the relays click.

What a great explanation! That was helpful to me.  Thanks!   Tubenit

[tubenit]

I have been collecting and drawing up some more relay information besides the great stuff Doug has already posted.

It is now in the ARCHIVES: 

http://www.el34world.com/Forum/index.php?topic=14348.new#new

With respect, Tubenit

[EL34]

I made you a relay board you can test and threw it into your order.

It's a bit of a pain doing this with turret lugs
A well done PC board may be easier to work with

The board is 3.1 inches x 1.1 inches

I laid out the relays side by side because my 3.125" board material is not wide enough to put the relays end to end
This arrangement may work out better
All the coils are on one side and all the switched wires can leave the other side

[tubenit]

Wow!!  Very kind of you!  THANKS! 

Very generous of you & I will look forward to using it. I'll try to post some pics of the relay system once installed and working and a new layout to show how I installed it in the D'Mars ODS.

THANKS,  Tubenit

[EL34]

Not sure how or where you are going to mount it
A single standoff or maybe two may work to bolt it down
Or hot glue an insulator to the back and then hot glue it down to the chassis?

The connections are so close together, it may be hard to wrap the wires around the lugs with the relay sockets in place.
You may have to wire it all up first and then add the relay sockets?

[tubenit]

CHECK for errors!

This is a draft drawing of how I will hook up Doug's relay board to the D'Mars OD Special

Switch #1 =    clean/OD
Switch #2 =    midboost
Switch #3 & 4  =     clear OD/ FAT OD


With respect, Tubenit

[DummyLoad]

7805 needs an output bypass cap. improves stability, transient response and prevents oscillation of VR. 22-100uF should do. connects from Vout to GND. use a VR protection diode - diode is strapped from Vout to Vin pins of VR, cathode end tied to Vin pin - use 1N4002 or similar.

where are points N, V, OD1, and OD2 connected?

great work TN. 

--DL

[tubenit]

7805 needs an output bypass cap. improves stability, transient response and prevents oscillation of VR. 22-100uF should do. connects from Vout to GND.

Can you show me a schematic of what you are talking about?  Not sure what to think?  The concept of the output bypass cap was brought up in another thread. Some individuals think it's important .......... others don't? 

use a VR protection diode - diode is strapped from Vout to Vin pins of VR, cathode end tied to Vin pin - use 1N4002 or similar.

I don't know what you are referring to here?  My layout shows using a voltage regulator per Sluckey's suggestion.

A schematic would sure help, please?

With respect, Tubenit

[EL34]

Jeff,
The drawing Sluckey did is just fine for a simple relay coil power supply.

[EL34]

I would have the larger 4700uf filter cap on the out side of the regulator

[sluckey]

DL's protection diode would be mounted directly across the input and output terminals of the regulator chip, cathode to input terminal. I've never used one and I know that a lot of FAA equipment doesn't use the diode. It certainly won't hurt anything and just 'might' save your $1 reg. chip someday. I wouldn't bother in a relay power supply. See attached pic, or refer to page 8 of this datasheet for the rest of the story...

http://www.sparkfun.com/datasheets/Components/LM7805.pdf

As for the output cap... If I was using the 7805 (or any 3-terminal regulator) to provide power to logic circuits, or op-amps, or anything other than a relay or LED, then I'd put a 0.1uF cap on the output. The cap probably won't give any benefit for a relay coil or LED though. I do have output caps on my +9 volt pedal board power supply.

[tubenit]

EL34 & Sluckey,

THANKS!  I think I'll skip the protection diode. I can always solder in a new 7805 voltage regulator if needed.

I think what I will do is put a 350uf prior to the input of the voltage regulator and the 4700uf after the voltage regulator prior to the relay. I don't see that the 350uf prior to the VR will hurt anything & I should have room for it.

With respect, Tubenit

[sluckey]

Always put the big cap prior to the regulator, ie, just after the rectifier. The 350 ain't needed.

[Geezer]

Always put the big cap prior to the regulator, ie, just after the rectifier. The 350 ain't needed.

Steve, could you draw out what you are proposing? I think T is getting conflicting info/suggestions from you & Doug (at least that's what I'm reading?)

Geezer

[sluckey]

Here's my orig. dwg from the D'Mars thread... I think Tubenit has a handle on this. I still think this minimal circuit will happily drive lots of Doug's relay coils. All the other things people have mentioned, ie, extra caps, diode protection are good ideas but IMO are wasted on a supply that will only be energizing a relay coil. The ONLY thing I might add would be a 0.1uF cap between the output and ref terminals.

I do have a small can of worms to open but I'll let the dust settle on this first.
 

[tubenit]

I thought I'd post a couple of pics showing the current stage of installing Hoffman's relay switching.

It took a little time to figure out how to thread the wire around the tight turrets and solder it, but it went reasonably quickly and turned out reasonably neat, IMO.

I really like the compact size of the "test" relay board that Doug gave me to try out.  

With respect, Tubenit

[sluckey]

I would connect the IN4007 end that has the stripe (anode) to the positive end of the coil?   CORRECT?

Yes and no. Yes, connect the striped end of the diode to the positive end of the coil. But the stripe is the cathode, not the anode.

[tubenit]

Yes and no. Yes, connect the striped end of the diode to the positive end of the coil. But the stripe is the cathode, not the anode.

THANK you!  I appreciate the response. Thinking about it, it makes sense that it's the cathode and not the anode.  I will connect the striped cathode to the positive end of the coil.

With respect, Tubenit

[EL34]

In your photo, the red line is pointing to the correct V+ lugs on my board but in your diagram

The top view is the correct view when looking down at the relay and turrets from up above

Your .gif image was pointing to the bottom view

The images I posted in reply #10 show the correct top view with V+ and V-

Looking good.
Things look a bit tight
Lots of wires going to that little board huh? 

[EL34]

Your pictures are all correct

If you rotate all the pictures and diagrams so that the coil contacts are at the bottom of the image, they are all correct
The image above needs to be rotated 180 degrees and then it looks just like what you have in your photo's

V+ is on the right

Here is the correct top down view rotated 4 ways

[tubenit]

WHAT ???? 

Now I am back to being confused. 

Is this picture CORRECT???

[tubenit]

OK,  looks like we're saying the same thing.     

THANKS! 

Tubenit

[EL34]

yes, the picture is correct

The CAD drawing I sent you should be the easiest to understand
The CAD drawing is just as if you were looking down at the board
The V+ and V- are marked on my CAD drawing

[tubenit]

THANKS!  Sorry for my confusion. Wasn't trying to be thick, just wasn't registering for some reason & needed to make sure I understood what was being said. 

I truly appreciate your help.

With respect, Tubenit

[tubenit]

OK, Sluckey and Geezer have been helping me with wiring of the foot switch for this relay system and the D'Mars OD Special project.

This is an update.  

We're still working on it & eventually all the "corrected & edited" info will be in ARCHIVES for future reference.

With respect, Tubenit

[EL34]

The diagram is looking good

[tubenit]

Doug's relay board worked.  Clean channel was super quiet.  OD1 was reasonably quiet.

I took Doug's "test"  board out and I am now trying another method that will be easier to service and mod, IMO.

It did take a while to make the small boards.  They are 1.18" X 2.75" (each).  However, even though it took a while to make the boards, it saved alot of time wiring up compared to the small "test" board.

With respect, Tubenit

[Tone Junkie]

That how i like them.  I was running the wires underneath from 1 hole to the other untill I layed the soldering iron on to long once and my buss wire fell out. works much better your way
Bill     

[tubenit]

The relay system and relay layout board in reply/post #34 works GREAT!  They are very quiet relays.  I was not sure at first about that but I discovered two things:

1:   I found using the Hoffman D'Mars board that I needed shielded wires going to the treble pot from the .002 and .02 caps on either   
      side of the wiper.  Something about crossing the B+ created some hum.   

2:   I tended to use shielded wires on any long runs to the relays also.  IF you feel like you lose some "high frequencies" from the
      shielded wire then use an 82p cap on the OD trim pot from wiper to the non-grounded terminal side.

I am very happy with Hoffman's relay parts!  Nice stuff.

With respect, Tubenit

[kagliostro]

May be Doug decide to make available boards like those of post #34

K

[tubenit]

I've continued to work on layout and wiring around these relays and have it remarkably quiet now, IMO.

Some thoughts from my experience with this:

Place the relays as close to where you want the switchin done to minimize long runs. Also I think having each relay be on a separate board would be best for ease of wiring and placement. (Just an opinion on that)

Use shielded wires around tight fits around relays and on long runs. I did not find this to lessen clarity or harmonics on my amp which surprised me.

Lastly,  Doug's relays are VERY quiet.  I initially wasn't sure if that was the case.......... HOWEVER, it was my layout and grounding that induced some hum. 

Now my D'Mars ODS  with OD engaged is quieter at idle than the original '76 Princeton Reverb amp I owned.  On the clean engaged, it is just about dead quiet. I mean you have to really listen to hear the amp is on.  And those noise levels are with the amp cranked somewhat higher than the volume I normally play at home.  In other words, if you heard the amp on "clean" and then I played a chord ...... I think the volume would possibly be startling given how quiet the amp was at idle.

With respect, Tubenit

[EL34]

Good info
I was wondering if those 4 relay boards were ideal or not.

[EL34]

Jeff,
I was looking at your colored diagram in post #34
looks like you are trying to light up LED's when you step on a footswitch?

But I don't see any power going to your foot switches

I drew up this diagram of how I would do it
Note that you must send 5 volts from your power supply down the wire to the foot switch box

[tubenit]

Essentially, I am doing as your schematic shows and the LED lights worked perfectly.   NC is lit.  NO is not

With respect, Tubenit

[TIMBO]

Hi guy's, Going to do some footswitching with relays in my next build. This might be a no brainer but is there a preferd on/off when engaging the circuit?? That is, is it better to have the relay ON when the OD circuit is NOT used or relay ON ONLY when the OD circuit IS used.  Thanks

[tubenit]

You  want the relay normally closed with the OD engaged.  You want the clean to be activated by the relay. The reason for this is IF the relay induces some hum it will be less noticed on clean.

[Geezer]

You  want the relay normally closed with the OD engaged.  You want the clean to be activated by the relay. The reason for this is IF the relay induces some hum it will be less noticed on clean.

Also, that happens to work well with the way the LED's are run.....when the relay is engaged (Clean active), the LED is OFF. When the relay is NOT engaged (OD active), the LED is illuminated.

[EL34]

May be Doug decide to make available boards like those of post #34

Well, not exactly like that, but better, IMO

see this post
http://www.el34world.com/Forum/index.php?topic=14468.msg137126#msg137126