ricothetroll

Relay True Bypass
« on: September 14, 2009, 08:00:06 AM »
Hi !

I just drawn that schematic :



That's in order to have a true bypass on my GSSL, controlled by a single switch. The idea of relays is that it's quite impossible to find 8PDT hardwire switch.

I found that relay that migt work for it :
http://be.mouser.com/ProductDetail/Tyco-Electronics/D3002/?qs=HTr%252boA4jRiklpi5eOqZK2A%3d%3d

As it's the first time a draw a schematic with relays, I'd like to have some opinions on the design, and also, feel free to comment about the main idea of it !

Thanx in advance !

Eric
« Last Edit: September 14, 2009, 08:01:38 AM by ricothetroll »


Speedskater

Re: Relay True Bypass
« Reply #1 on: September 14, 2009, 08:39:41 AM »
So, why does it have to be one relay?  Four separate relays would be easy to find, the cost should be less and channel cross-talk might be lower.
Kevin

hobiesound

Re: Relay True Bypass
« Reply #2 on: September 14, 2009, 08:53:41 AM »
you might want to add a diode across the coil of the relay to protect it.


greetings,

Thomas

ricothetroll

Re: Relay True Bypass
« Reply #3 on: September 14, 2009, 09:41:54 AM »
Quote
So, why does it have to be one relay?  Four separate relays would be easy to find, the cost should be less and channel cross-talk might be lower.

Hm, Rel1...4 are separate relays, all controlled by one switch !

Quote
you might want to add a diode across the coil of the relay to protect it.

do you mean something like this ?

(I'll have a "hardware" switch instead of Q1)
« Last Edit: September 14, 2009, 09:43:32 AM by ricothetroll »

JohnRoberts

Re: Relay True Bypass
« Reply #4 on: September 14, 2009, 09:58:04 AM »
I have done this before in products.  I power the relay(s) from a separate unregulated PS that has a small reservoir capacitor so it collapses quickly after power is removed. A short delay after power up gives the circuitry time to settle before connecting. 

Yes, diodes are commonly used to catch inductive spikes.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

sahib

Re: Relay True Bypass
« Reply #5 on: September 14, 2009, 10:01:20 AM »
That diode is not for protecting the relay but for the active device that controls it. It prevents inductive kick dumped back on the active device and damaging it. Even if you are controlling it with a mechanical switch, it is still a better practice to use the diode.

ricothetroll

Re: Relay True Bypass
« Reply #6 on: September 14, 2009, 05:23:51 PM »
thanx a lot for those answers !

that reservoir capacitor looks like a great idea. how do you determine its value ?

JohnRoberts

Re: Relay True Bypass
« Reply #7 on: September 14, 2009, 05:45:47 PM »
empirically...

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.


 

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