Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Solid State => Topic started by: tubenit on April 09, 2010, 08:58:12 am
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When I initially built by T-Lite 5879 OD, I did not plan for a relay and there is very little space on the front panel.
Anyone have some tips on location for the relay and wiring tips. I'm using a DPDT mini-toggle currently. The DPDT is on the front panel, can the relay isolated jack be on the back panel?
The photos are not the current T-Lite but it is the same chassis and basic layout. I gutted the tagboard and have heavy duty terminal strips in now which are laid out similar.
I am thinking of mounting a relay board where I have the red X showing. Is this headed the right direction? And with the DPDT on the front ......... what about the isolated relay jack being on the back?
With respect, Tubenit
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Hi Jeff,
I would try to get the relay as close as possible to whatever signal you are switching. Your DPDT switch on the front panel is fine, just keep the power and ground for the relay switching separate from the audio ground. Are you using one of Weber's relay boards, or just perfboarding your own? Also, what is the purpose of the jack? Is is a footswitch jack, or is it for audio as well?
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What Scott said. You can put the relay isolated jack where ever you want, it's just the control voltage for the relay.
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I hope you plan on making it footswitchable too.
I concur about placing the relay right where it's needed and grounding away from audio signal grounds.
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Yeah, I thought I'd try to just purchase a finished relay board for the first attempt.
The isolated jack will be for an on/off foot switch.
So it sounds like I can put the isolated jack on the back panel since it's just controlling the voltage.
Sounds like I need the relay as close to the dpdt switch and signal wires as possible. Not sure I can get it much closer than where I put the X given the size of the board. I don't think I have room between the pots and terminal strips. And the OD channel with signal is in the V2 position.
Worth a try mounted where the X is? Or is that gonna likely be problematic?
With respect, Tubenit
With respect, Tubenit
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Here is a recent thread of relay discussion.
http://www.el34world.com/Forum/index.php?topic=9104.0
I would keep the grounding floating which means you have to use isolated jack for relay control.
- use full wave rectifier for coil voltage
- use big caps for filtering
- use star grounding for relay ground
- connect a small cap over the voltage pins
- wire the relay so the higher gain channel is active when the relay coil is off
/Leevi
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The D'Lite layout is perfect for noise and grounding.Follow that layout and you will not have an issue.
I have used isolated foot switch jacks or metal switchcrafts with no issues at all.No pops,no noises.The jack simply switches the grounds which activates the relay.
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Right under V2, in the middle of your chassis would be ideal, but you may have to re-route some wiring to accommodate that location. If you can't, then where you've drawn the X might work, although it's pretty close to the input circuitry. I put a relay board in my Hellhound and the only place to put it was near the input, but it works fine. I'm only switching one triode stage in/out though, so that may make a difference. It's not critical how far away the jack or DPDT switch is.