True Bypass With Relays (balanced)
« on: March 28, 2005, 10:11:44 AM »
This might be a long shot, but does anybody have boards for adding relays to  add a "true bypass" switch to a blanced device?

If not a board, what about a schematic?

Also, does the relay need to be close to the output jack or output of board to see a benefit? I.E. Would it be silly to mount the relay on the back of the switch on the front panel?

Doug


amorris

True Bypass With Relays (balanced)
« Reply #1 on: March 28, 2005, 11:04:00 AM »
you still have to power the relay(5volts or 12 volts etc..) and use the switch to activate the relay, right? that would seem better to use a pcb for such a job. the switch would handle the 5 volts, not the signal. sounds like you were thinking of using a multi-pole switch by your post.

True Bypass With Relays (balanced)
« Reply #2 on: March 28, 2005, 11:30:01 AM »
Hmm...

I was just looking to see if anybody had pcbs for sale that are setup to provide true bypass for a device.

I realize that I'd new a spst switch for triggering the relay. I was just curious if the relay could be mounted on the same pcb as the switch or if it needed to be by the input/output.

Also, I am not sure what kind of relay to get, as I've never done anything with relays b4.

I am also not sure what the shcemtic would look like.

Doug

R.G.

True Bypass With Relays (balanced)
« Reply #3 on: March 28, 2005, 11:30:48 AM »
Quote
you still have to power the relay(5volts or 12 volts etc..) and use the switch to activate the relay, right? that would seem better to use a pcb for such a job. the switch would handle the 5 volts, not the signal. sounds like you were thinking of using a multi-pole switch by your post.

See http://geofex.com/FX_images/ltchrly.gif for a way around some of this. The circuit pulses the set and reset lines of a latching relay, which then does not require further power to hold its position. The circuit included slow-down circuits on the relay coils to suppress capacitive feedthrough of the coil voltage transient as well.

If you're true-bypassing a balanced (blanced??) circuit, you'll need a 4PDT equivalent. I think it might make more sense to use two DPDT relays. The NEC EA2 relay is very workable and quite reasonably priced. Use two of them.

True Bypass With Relays (balanced)
« Reply #4 on: March 28, 2005, 11:36:07 AM »
Schematic

What kind of transister would you use?

What is a 1/6 CMOS hex inverter?

What is the symbol all the way to the right?

This looks like it will work off just +V. What voltages will work?

-----

NEC EA2 relay

I was checking out mouser and there are tons of options.

Latching, Single Latch, Double Latch, Voltages, COIL,  etc...

Doug

Bauman

True Bypass With Relays (balanced)
« Reply #5 on: March 28, 2005, 11:40:32 AM »
Man, Igor (I think) have a cool one, the relays are next to the input XLR's, there's  a board layout, very cool. I just have so much files, a total mess, can find it!!!!  :evil:

 :sam:
Fabio
cheers!
Fabio
_____________________
www.thediypill.com/store

True Bypass With Relays (balanced)
« Reply #6 on: March 28, 2005, 11:44:50 AM »
No sh*t!

Damn that sucks! That is what I was thinking.....

Well if you can dig up, please send..

dug +at+ dugdesign +dot+ com

R.G.

True Bypass With Relays (balanced)
« Reply #7 on: March 28, 2005, 11:46:34 AM »
Quote
What kind of transister would you use?

I would use a 2N3904. Or any other 100ma NPN/40V device.

Quote
What is a 1/6 CMOS hex inverter?

In the family of CMOS logic circuits, some of the chips have six inverters (that is high voltage in gives low voltage out, and vice versa) in a single DIP package. These are called "hex inverters". Suitable types are 4049, 4069, 40106, 74C14, some others.

Quote
What is the symbol all the way to the right?

The thing with the vertical dotted line through it is the relay. Two coils and two contact sets.

Quote
This looks like it will work off just +V. What voltages will work?

In fact, it is designed for a single voltage; the nominal is 12Vdc so you can use the easily available 12Vdc relays.

True Bypass With Relays (balanced)
« Reply #8 on: March 28, 2005, 12:00:46 PM »
For the symbol, meant the thing to the left, but now I think it makes sense, it is a momentary switch?

For the relay, I am still unsure of all the terms and what I would need to get.

For the shcmatic.. I don't think I require latching. I think a SPST switch that controls V+ to the relay would be fine, do I still need other components?

Doug

dukasound

True Bypass With Relays (balanced)
« Reply #9 on: March 28, 2005, 12:53:35 PM »
Hi
One year ago I made board for True Bypass (balanced) with ordinary relays.
It have 78xx voltage regulator for adequate relay┬┤s voltage.

Duka


True Bypass With Relays (balanced)
« Reply #10 on: March 28, 2005, 01:02:25 PM »
Do you have anymore of these boards?

What voltage do they run on?

What relays did you use?

Is that 22uF 100V or 100uF 22V?
Regardless, that isn't a very large filter cap. Is there a reason it is small?

Doug

dukasound

True Bypass With Relays (balanced)
« Reply #11 on: March 28, 2005, 01:05:22 PM »
Quote from: "thedug"
Do you have anymore of these boards?

What voltage do they run on?

Doug

No, but I can send you pdf. I run 6V for relays what I had, If you have 12V relays 7812 would be good.
Duka

True Bypass With Relays (balanced)
« Reply #12 on: March 28, 2005, 01:08:23 PM »
Please do send a pdf, to dug _at_ dugdesign _dot_ com.
I might try to make one that has pads for pdb xlrs.  =P

PS: I added some questions to the above post.

Will +6V relays work ok? Now to figure out how to get +6V from an 18V sontec... hmm..

dukasound

True Bypass With Relays (balanced)
« Reply #13 on: March 28, 2005, 01:15:13 PM »
Quote from: "thedug"
Please do send a pdf, to dug _at_ dugdesign _dot_ com.
I might try to make one that has pads for pdb xlrs.  =P

PS: I added some questions to the above post.

Will +6V relays work ok? Now to figure out how to get +6V from an 18V sontec... hmm..

OK I will send you just to convert from Corel.
I used in many my project 6V relays.
Cap is 22uF-100uF and it is not critical. For 7806 you must have from 8VDC just to have right voltage to feed relay.
Duka

Mark Burnley

True Bypass With Relays (balanced)
« Reply #14 on: March 28, 2005, 01:16:07 PM »
Doug,

This is the simplest switch-and-relay bypass schematic:



If you can get a bit of Veroboard/matrixboard, it'd be very simple to build.

 :thumb:

Mark
O_O tape is life O_O

dukasound

True Bypass With Relays (balanced)
« Reply #15 on: March 28, 2005, 01:20:50 PM »
Quote from: "thedug"
Please do send a pdf, to dug _at_ dugdesign _dot_ com.

I did it :grin:

Mark Burnley

True Bypass With Relays (balanced)
« Reply #16 on: March 28, 2005, 01:23:57 PM »
Ha!

Duka got in with his great looking board as I was drawing that schem- it's essentially the same setup.

6V from 18V can be 7805 voltage regulator with two series connected 1N4001 diodes in the Common/0V lead connected to 0V. You may want to add a series resistor as well before the regulator to drop the voltage a bit.
Pop a heatsink on the 7805 too.

Mark
O_O tape is life O_O

dukasound

True Bypass With Relays (balanced)
« Reply #17 on: March 28, 2005, 01:36:45 PM »
Quote from: "Mark Burnley"
Doug,

This is the simplest switch-and-relay bypass schematic:



If you can get a bit of Veroboard/matrixboard, it'd be very simple to build.

 :thumb:

Mark

Nice Mark :thumb:  
Mine is for stereo and I think it is similar. You better make this because in off position signal is bypassed.

True Bypass With Relays (balanced)
« Reply #18 on: March 28, 2005, 01:37:29 PM »
Do you just mean to use 1N4001s for the 2 diodes at the regulator?

Or do I need to add extra diodes. What size resister would make sense?

If I have a +/- 18V supply, would the resiter possible load down the + side and mess up the regulation?

Doug

dukasound

True Bypass With Relays (balanced)
« Reply #19 on: March 28, 2005, 02:27:37 PM »
Quote from: "thedug"
Do you just mean to use 1N4001s for the 2 diodes at the regulator?

Or do I need to add extra diodes. What size resister would make sense?

If I have a +/- 18V supply, would the resiter possible load down the + side and mess up the regulation?

Doug

Two diodes are used in regulator circuit and they can be 1N4001-1N4007.
Here is a part from Thomas Uni PSU:

I preffer to use 4148 diodes paralel with relays coil .
I agree with Mark to decrease voltage if you have 18V. I dont remember but if you use 7805 or 7806 it can be about 10V.


 

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