Channel switcher PCB

[Lauri]

I thought maybe someone might find this useful. Here are gerber files for a multi channel switcher PCB: http://ghr.fi/tube/switcher/multichanne ... gerber.zip. It's a 2 layer PCB sized 74mm X 42mm.







http://ghr.fi/tube/switcher/multichanne ... gerber.zip

[dorrisant]

Nice work... but I don't know how excited I should be. Do you have a link for the circuit description from Merlin?

[chief mushroom cloud]

I just incorporated this very circuit into a piece of amp production equipment (to toggle amps on burn-in rack to monitor speaker outputs at o-scope)

[Lauri]

The gist of it is when a button is pressed a relay driver transistor turns on. Only one transistor will be on at a time.

You can find a description of how this kind of a circuit works here http://sound.whsites.net/project163.htm. Just scroll down to where it says Discrete CMOS Logic.

Nice work... but I don't know how excited I should be. Do you have a link for the circuit description from Merlin?

[tristanc]

Very cool.

[V2]

What is V+ for this circuit?

[Lauri]

What is V+ for this circuit?

Maximum recommended supply voltage for 40175 is 15V. V+ can be anything from 5V to 15V. Most likely you will want to use either 5V or 12V depending on what relays you're using.

[brejna]

Interesting project. Can individual switches be turned off, like pedal? So you have radio button option between 4 switches and option to bypass all?

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[kdmay]

Great project!

I’ve had some of these made and in the next few weeks will incorporate into a 4 channel amp, so will report back.

Quick question: can 2 of these chips be used simultaneously for 8 channels? Wondering how the flip/flop reset would work in this instance

Cheers

[chief mushroom cloud]

Quick question: can 2 of these chips be used simultaneously for 8 channels? Wondering how the flip/flop reset would work in this instance

Yes. We used this circuit for a set of amp monitoring and burn-in units in mfg....with two of these circuits per unit (8ch) and linked for a total of 24 ch...just connnect the CLK pins together.
Haven't tested more than that. Might need bi-directional buffer between CLK circuit sets if cable L get too long. We just use std midi cables to link clk and audio. Also used CD40xx buffers to drive relays...but I would use 2N7000 or similar to lo-side switch relays and LEDs for anything under 8ch. Also, DON'T share your relay logic gnd w/ your audio gnd.....reference terminate it at chassis common.

[dorrisant]

Very nice... I am a bit excited now, gotta try it out. Thank you very much for posting!

[kdmay]

[quote="chief mushroom cloud" post_id=397727 time=1556724621 user_id=54]
[quote=kdmay post_id=397613 time=1556499639 user_id=9465]
Quick question: can 2 of these chips be used simultaneously for 8 channels? Wondering how the flip/flop reset would work in this instance
[/quote]
Yes. We used this circuit for a set of amp monitoring and burn-in units in mfg....with two of these circuits per unit (8ch) and linked for a total of 24 ch...just connnect the CLK pins together.
Haven't tested more than that. Might need bi-directional buffer between CLK circuit sets if cable L get too long. We just use std midi cables to link clk and audio. Also used CD40xx buffers to drive relays...but I would use 2N7000 or similar to lo-side switch relays and LEDs for anything under 8ch. Also, DON'T share your relay logic gnd w/ your audio gnd.....reference terminate it at chassis common.
[/quote]

Thanks mate

I am actually planning on building an 8 channel amp and 4 channel cab switcher, so this is helpful!

In the amp build I mentioned I am trialling this, I am definitely not going to share the logic ground with the audio ground. A buddy did this with one of the Tube Town Midi boards and had all sorts of troubles so had already warned me on this.

[dorrisant]

Yes. No reason to ground it to the chassis.

[azatplayer]

I’ve bread boarded this circuit and works well. However on power on, all switches are on.
Is this normal behaviour? Kinda not useful if it is!
I’m sure I’ve done a thing wrong