8 Channel Relay Switch Build Thread

[Joe Malone]

Version 1 PCB


New Version 2 PCB


Schematic for Ver 2 PCB
http://www.jlmaudio.com/8CHRELAYSW/8%20Channel%20Relay%20Switch%20Ver2.pdf

Select option you are going to use and fit all parts to pcb in order shown in build map link below.
Option 1 - 26 pin IDC header JLM 8 BUS or option 2 - DB25 Tascam pinout.

Use step by step build map at this link http://jlmaudio.com/builds/maps/8_channel_relay_switch_map.html

If using 24vdc relay for example (V- could be 0v and V+ 24vdc) or (V- could be -12v and V+ +12v)

JLM 8BUS ribbon lays out directly into IDC DB25 type connectors as Tascam format as long as red stripe pin 1 of ribbon cable lines up with pin25 DB25 which is the second pin from the end. So pin 13 is left empty and ribbon cable pin 25 & 26 are not used and removed.

JLM 8BUS 26pin input/output (Same as on Passive Monitor Controller, DSUB4, TASCAM/IDC to XLR/TRS IN & OUT PCB/kits etc)
Pin 1 0v (Pin 1 Square pad on PCB)
Pin 2 Ch1-
Pin 3 Ch1+
Pin 4 0v
Pin 5 Ch2-
Pin 6 Ch2+
Pin 7 0v
Pin 8 Ch3-
Pin 9 Ch3+
Pin 10 0v
Pin 11 Ch4-
Pin 12 Ch4+
Pin 13 0v
Pin 14 Ch5-
Pin 15 Ch5+
Pin 16 0v
Pin 17 Ch6-
Pin 18 Ch6+
Pin 19 0v
Pin 20 Ch7-
Pin 21 Ch7+
Pin 22 0v
Pin 23 Ch8-
Pin 24 Ch8+
Pin 25 V+
Pin 26 V-

JLM 16 pin IDC relay control & power port
Pin 1 - 4 V- (Pin 1 Square pad on PCB)
Pin 5 Ch1
Pin 6 Ch2
Pin 7 Ch3
Pin 8 Ch4
Pin 9 Ch5
Pin 10 Ch6
Pin 11 Ch7
Pin 12 Ch8
Pin 13 - 16 V+

Connect Ch wire to V+ to switch relay from NC normally closed to NO normally open 26 pin 8BUS connector.

Enjoy.

[esencia]

Hi,

Is there further information explaining how it works?
I don't understand what is switching ..
From 8 inputs the relays what are they doing?
thanks

[Joe Malone]

Hi,

Is there further information explaining how it works?
I don't understand what is switching ..
From 8 inputs the relays what are they doing?
thanks

There are 8 balanced audio lines on a TASCAM DB25 format. The back common connector normally defaults to the NC Normally closed 8 channels. But each individual balanced channel can be switched to the NO Normally open 8 channels.

eg if you switched all 8 relays you can make a TASCAM DB25 8 channel change over switch. Or PA fire alarm mute switch. Or you can switch 1 to 8 channels to change over in any combo. The 26PIN IDC header on the pcb can just ribbon cable out DB25 IDC connectors.

[esencia]

Let me know if I understood you correctly
You mean that every input channel can be connected to the same channel output or not connected to it. Is it like and on/off per channel ?
Is not posible use it to select different output per channel? For channel 1 select output in channel 1 or channels 2 or channel 3 and so?

I'm looking for a pbc that allows me this:
input channel 1-8->output channel 1-8 (in st pairs)
two FX processors
For each of the FX processors I select which of the input channels will be routed to it (12,3-4,5-6,7-8) before going out to the same channel.
ie.
I select channel 7-8 for FX1, so input channels 1-2,3-4,5-6 will go directly to output channels 1-2,3-4,5-6 but channels 7-8 will go to FX1 firs and the output of FX1 will go to the channels 7-8 output.
Then, if for FX2 I select channel 5-6, 1-2,3-4 input channels will go to output 1-2, 3-4, but channels 5-6 will go to the FX2 and after that to there 5-6 output.
So I'd have 1-2,3-4 channels going directly to their same output, but channels 5-6, 7-8 will go to the FX1 and FX2 before going out again.

is it possible with this or other board?
thanks

[Joe Malone]

Let me know if I understood you correctly
You mean that every input channel can be connected to the same channel output or not connected to it. Is it like and on/off per channel ?
Is not posible use it to select different output per channel? For channel 1 select output in channel 1 or channels 2 or channel 3 and so?

I'm looking for a pbc that allows me this:
input channel 1-8->output channel 1-8 (in st pairs)
two FX processors
For each of the FX processors I select which of the input channels will be routed to it (12,3-4,5-6,7-8) before going out to the same channel.
ie.
I select channel 7-8 for FX1, so input channels 1-2,3-4,5-6 will go directly to output channels 1-2,3-4,5-6 but channels 7-8 will go to FX1 firs and the output of FX1 will go to the channels 7-8 output.
Then, if for FX2 I select channel 5-6, 1-2,3-4 input channels will go to output 1-2, 3-4, but channels 5-6 will go to the FX2 and after that to there 5-6 output.
So I'd have 1-2,3-4 channels going directly to their same output, but channels 5-6, 7-8 will go to the FX1 and FX2 before going out again.

is it possible with this or other board?
thanks

You would need 2 relay pcbs per FX processor. 6 wire ribbon cable around the NO IDC so 1,3,5,7 connected and 2,4,6,8 connected. 1 pcb would switch inputs and one pcb outputs. Switch OFF, 1&2, 3&4, 5&6, 7&8 so FX would inserted to by switch selection. You can do this in parallel or series in parallel you can no select same 1&2 FX1 & FX2. But in series you can select and 1&2 could have FX1 then FX2.

So basically you would need 4 pcb kits to do what you want.

If you want to do it very neatly with all ribbon cable and XLR or TRS for the Effects
4 x relay switch kits
4 x DSUB4 kits
4 x STEREO IN/OUT kit with XLR or TRS.

All would plug together with DB25 in and out for the 8 channels and TRS or XLR for FX. If you need all XLR or TRS use our Tascam to XLR/TRS PCB

[esencia]

Hi Joe,

As a fully explanatory (for dummies.. yes, I asume it ) description...
I've prepared a drawing un-completed to let you draw the connection (from-where) to be completely clear for me. I prepared it for you to the easiest/fast drawing with just a few lines.

Are those relay good ones for mastering quality use?
what kind of cable do you recommend me for inter-pcb connections to keep free of noise the signal?

thanks a lot.

[Joe Malone]

Hi Joe,

As a fully explanatory (for dummies.. yes, I asume it ) description...
I've prepared a drawing un-completed to let you draw the connection (from-where) to be completely clear for me. I prepared it for you to the easiest/fast drawing with just a few lines.

Are those relay good ones for mastering quality use?
what kind of cable do you recommend me for inter-pcb connections to keep free of noise the signal?

thanks a lot.

Schematic for Ver 2 PCB
http://www.jlmaudio.com/8CHRELAYSW/8%20Channel%20Relay%20Switch%20Ver2.pdf

The 22 Channel stereo switcher photo in the link below shows how the 6 wires can be rapped around the 26 pin IDC to link stereo pairs together.
https://www.facebook.com/jlmaudio1/photos/a.517935134888549/2088697217812325/?type=3&theater

[kante1603]

Hello Joe,

I‘ve ordered one of these kits (12vdc version),it is on its‘ way to me now.
I see there are two versions now and don‘t know which one I will receive.I‘m happy with either one.
Just in case it is V2:

1.:The added regulator is to add more stabilty (I‘m a bit concerned about 78xx type regs,personally had quite a few issues with latchup in my builds over the years)?


2.:If it is a 7812 (in my case) we will have to supply the board with ca. 15vdc or higher to start the reg. working,yes?


3.:What‘s the prefered physical point to hook up our dc feed wires,directly to Vin and GND of the regulator pins,maybe at the bottom pcb side?


Thank you in advance,

Udo.

[Joe Malone]

Hello Joe,

I‘ve ordered one of these kits (12vdc version),it is on its‘ way to me now.
I see there are two versions now and don‘t know which one I will receive.I‘m happy with either one.
Just in case it is V2:

1.:The added regulator is to add more stabilty (I‘m a bit concerned about 78xx type regs,personally had quite a few issues with latchup in my builds over the years)?


2.:If it is a 7812 (in my case) we will have to supply the board with ca. 15vdc or higher to start the reg. working,yes?


3.:What‘s the prefered physical point to hook up our dc feed wires,directly to Vin and GND of the regulator pins,maybe at the bottom pcb side?


Thank you in advance,

Udo.

HI Udo
It will be a version 2 pcb but with 12vdc relays just link over the reg position in and out with a wire.

To feed power in and 0v use the link the 4 wires at each end of the 16 pin ribbon cable for +V & 0v.

The other 8 wires will be your relay control inputs into the ULN2803. linking any of those wires to +12v will operate the relay.

[kante1603]

Thank you for the fast reply Joe.

But I‘m a bit confused now.
When will we use the regulator (and corresponding caps)?
I understood how the control port works and would have gone to feed my dc in Version 1 exactly there-because of four linked pads on each side.In version 2 it seems to be two pairs each side for dc both pre and post regulator.
I‘m o.k. with linking them,but want to know what the purpose of the regulator is.

Thank you in advance,

Udo.

[Joe Malone]

Thank you for the fast reply Joe.

But I‘m a bit confused now.
When will we use the regulator (and corresponding caps)?
I understood how the control port works and would have gone to feed my dc in Version 1 exactly there-because of four linked pads on each side.In version 2 it seems to be two pairs each side for dc both pre and post regulator.
I‘m o.k. with linking them,but want to know what the purpose of the regulator is.

Thank you in advance,

Udo.

The regulator is for dropping the volts for the ULN2803 inputs. As when running 24vdc into the ULN IC it can heatup the ULN just because of the input reference resistors load.

The caps are always used.

[kante1603]

Aaaaaahhhhhaaaahhhh!
That clears it up,thank you Joe.
So if we use 24vdc relais we use 24vdc as supply voltsge and put in a 7812 for the ULN 2803,right?
I think confusion came from the schematics.Because the dc feed to the relais is written as „V+“ which is after(!) the regulator.
I will find out when I receive the board by following traces anyway.

Thanks again,

best regards,

Udo.