Pbms designing my control panel

Frisbee78 · 6th May 2004, 05:52 PM

Hi all

Here the situation:
My amplifier uses a couple of quadripolar inverter switches to control its bridging commuting & stuff.
But since they're ugly & all, I want to design a little circuit to toggle a pair of relays through a couple of push-buttons.

The idea is to toggle the relay by pressing once on the push-button and toggle back when pressing it again.
I also want the circuit to remember the settings and forbidding any change when the amplifier is off.

A couple of latched relays could be the easiest, but I haven't been able to find anything suitable and I bough the 'classic' relays already.

I tried to use flip flop gates (CD4013) and AND gates (CD4083) but didn't get any design to work. I went for CMOS because my PSU is in 12v.

Any ideas and comments welcome.

Frisbee78 · 11th May 2004, 06:27 PM

I'm surprised I haven't had any suggestions

Is designing such a board really that difficult? If so, I won't feel bad for failing

johnnyx · 11th May 2004, 07:51 PM

I'll have a go.
The hard bit is remembering the setting when power is off. You could use the 4013, and provide a battery so that it can save its state, similar to a memory backup battery circuit for computers. A 3V Lithium cell should be sufficient to maintain the state, use a small diode eg 1N4148 to prevent the cell from blowing up with 12V across it. You would have to make sure that when power is restored, it doesn't change state, and that nothing but the CMOS chip draws battery current. Using a MOSFET to switch the relay would help.
I suspect that the problems you had trying to get the 4013 to work was due to switch bounce. The switch needs de-bouncing, a pair of cross-coupled NAND gates would do the job, using a changeover push switch. A single pole make switch could be de-bounced with a time delay circuit - it depends what you have.
It cannot change state with no power to the switch circuit or the relays, but when power is restored the relay will switch according to the state that the 4013 is in.
Hope this helps.

imix500 · 12th May 2004, 12:10 AM

Is it ok to be switching modes like that with the amp powered up?
I'm assuming you're speaking of 2X voltage mode (bridging) for the amp. Crown's pro audio amps do it with a simple 3 position slide switch, though I'm not positive how they do the input inverting and such with one switch.
But I've always been told to power down before changing amp modes.

Frisbee78 · 12th May 2004, 01:13 AM

johnnyx, thanks for your suggestions. They sound good. I am not sure how to implement a Lithium cell without blowing the stuff sky high in the crcuit but I'll do some research.
I use 2N3904s to toggle the relay, that works a treat.
I guess my next problem is switch debouncing. The switch is SPNO and I have tried a few deboucing methods (RC network, NAND gates...) but none have been very conclusive. Next I'll try to use a 555 timer and see what that does. Just was reluctant to this solution due to the number of components involved...

imix500, thanks for bringing this issue to my attention. What the switch does is:
- toggle a relay that feeds inverted signals in the left and right blocks (when bridged) instead of the left & right signals (when on stereo mode)
- toggle system inputs on a security circuit
Now the signal toggling shoud take live switching no problem. But the control circuit might want to be correctly setup at power up. I'm not sure about that tho but to be on the safe side, I think I'll keep the bridging/stereo toggling when powered off.
The control panel I'm after here will still needed for the vumeter controls.

One of these days I'll post the design of this amp...

Frisbee78 · 12th May 2004, 01:31 AM

Quote:

One of these days I'll post the design of this amp...

Well here goes:
It's in French and they are big files

Part 1:
Page 01
Page 02
Page 03
Page 04
Page 05
Page 06
Page 07
Page 08
Page 09
Page 10

Part 2:
Page 01
Page 02
Page 03
Page 04
Page 05
Page 06
Page 07
Page 08
Page 09
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18

Part 3:
Page 01
Page 02
Page 03
Page 04
Page 05
Page 06
Page 07
Page 08
Page 09
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20

6th May 2004, 05:52 PM	#1
Frisbee78 diyAudio Member Join Date: Jan 2004 Location: Leeds, West Yorkshire	Pbms designing my control panel Hi all Here the situation: My amplifier uses a couple of quadripolar inverter switches to control its bridging commuting & stuff. But since they're ugly & all, I want to design a little circuit to toggle a pair of relays through a couple of push-buttons. The idea is to toggle the relay by pressing once on the push-button and toggle back when pressing it again. I also want the circuit to remember the settings and forbidding any change when the amplifier is off. A couple of latched relays could be the easiest, but I haven't been able to find anything suitable and I bough the 'classic' relays already. I tried to use flip flop gates (CD4013) and AND gates (CD4083) but didn't get any design to work. I went for CMOS because my PSU is in 12v. Any ideas and comments welcome.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Panel resonance control	markp	Multi-Way	13	11th January 2004 12:45 AM
Designing for guys who like designing	Sch3mat1c	Tubes / Valves	14	31st August 2003 11:46 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

11th May 2004, 06:27 PM	#2
Frisbee78 diyAudio Member Join Date: Jan 2004 Location: Leeds, West Yorkshire	I'm surprised I haven't had any suggestions Is designing such a board really that difficult? If so, I won't feel bad for failing

11th May 2004, 07:51 PM	#3
johnnyx diyAudio Member Join Date: Jan 2004 Location: manchester	I'll have a go. The hard bit is remembering the setting when power is off. You could use the 4013, and provide a battery so that it can save its state, similar to a memory backup battery circuit for computers. A 3V Lithium cell should be sufficient to maintain the state, use a small diode eg 1N4148 to prevent the cell from blowing up with 12V across it. You would have to make sure that when power is restored, it doesn't change state, and that nothing but the CMOS chip draws battery current. Using a MOSFET to switch the relay would help. I suspect that the problems you had trying to get the 4013 to work was due to switch bounce. The switch needs de-bouncing, a pair of cross-coupled NAND gates would do the job, using a changeover push switch. A single pole make switch could be de-bounced with a time delay circuit - it depends what you have. It cannot change state with no power to the switch circuit or the relays, but when power is restored the relay will switch according to the state that the 4013 is in. Hope this helps.

12th May 2004, 12:10 AM	#4
imix500 Proud Union Member diyAudio Member Join Date: Mar 2004 Location: Nashville, TN	Is it ok to be switching modes like that with the amp powered up? I'm assuming you're speaking of 2X voltage mode (bridging) for the amp. Crown's pro audio amps do it with a simple 3 position slide switch, though I'm not positive how they do the input inverting and such with one switch. But I've always been told to power down before changing amp modes.

12th May 2004, 01:13 AM	#5
Frisbee78 diyAudio Member Join Date: Jan 2004 Location: Leeds, West Yorkshire	johnnyx, thanks for your suggestions. They sound good. I am not sure how to implement a Lithium cell without blowing the stuff sky high in the crcuit but I'll do some research. I use 2N3904s to toggle the relay, that works a treat. I guess my next problem is switch debouncing. The switch is SPNO and I have tried a few deboucing methods (RC network, NAND gates...) but none have been very conclusive. Next I'll try to use a 555 timer and see what that does. Just was reluctant to this solution due to the number of components involved... imix500, thanks for bringing this issue to my attention. What the switch does is: - toggle a relay that feeds inverted signals in the left and right blocks (when bridged) instead of the left & right signals (when on stereo mode) - toggle system inputs on a security circuit Now the signal toggling shoud take live switching no problem. But the control circuit might want to be correctly setup at power up. I'm not sure about that tho but to be on the safe side, I think I'll keep the bridging/stereo toggling when powered off. The control panel I'm after here will still needed for the vumeter controls. One of these days I'll post the design of this amp...

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)