Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Effects => Topic started by: tubenit on June 01, 2010, 08:25:11 am
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A few yrs ago, I used one of Doug's 9 terminal ft.switchs & effects boxes to make a true bypass pedal with an LED run off a 9 volt battery.
I used it ONE time with the band! Probably the most useless project I ever did (cause I started using effects loops and noise was no longer an issue).
Well, I want to convert that to a simple on/off switch with LED (9volt) to use to switch a relay on my new (cathode biased) Dumblish build.
Anybody have a schematic they can share that would help me out?
The jack on the amp is isolated from the chassis, so I am not sure exactly what I need on the ft.pedal box? Perhaps just do the same thing and isolate it or use a switched/grounded jack?
Thanks, Tubenit
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Jeff, I'd just keep it very simple. Don't use a jack on the footswitch. Just pass the cable thru a grommet or strain relief clamp and use a cable tie to secure the cable to the switch. Here's the modified schematic.
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THANKS again for your help, Sluckey!!! I am appreciative. I can figure it out from there with the schematic your provided.
Best regards, Jeff
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OK, got to thinking about this over my lunch break...........
For convenience, I think it would be even easier for me to use a guitar cord and have a jack on the ft.switch?
So I am thinking a isolated non-grounded jack like I'd use for a speaker jack on both the amp and ft.switch? Correct?
Seems like there would be no purpose with the relay in having a grounded switch jack like on input jack?
With respect, Jeff
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For convenience, I think it would be even easier for me to use a guitar cord and have a jack on the ft.switch?
So I am thinking a isolated non-grounded jack like I'd use for a speaker jack on both the amp and ft.switch? Correct?
Seems like there would be no purpose with the relay in having a grounded switch jack like on input jack?
OK. But does all that thinking, more parts, and labor really sound more convenient to you than cutting a plug off a guitar cord and hard wiring to the footswitch? :grin:
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OK. But does all that thinking, more parts, and labor really sound more convenient to you than cutting a plug off a guitar cord and hard wiring to the footswitch?
That's a fair question. Thanks. :wink:
Jeff
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I think the existing hole in those boxes where the cable enters is too close to the "floor" to conveniently mount a jack. I'd like to be able to find a source for a blank/undrilled version of that box, but I've never seen them offered that way.
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I think the existing hole in those boxes where the cable enters is too close to the "floor" to conveniently mount a jack.
That box is a blank box I got from Hoffman Parts. Look at where the holes are in the inside of the chassis photo. They're about the same as most effects pedals I think.
http://www.hoffmanamps.com/MyStore/perlshop.cgi?action=template&thispage=Chassis&ORDER_ID=246883208
With respect, Tubenit
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I was just poking you. I know you're talking about convenience of use, not building.
All the footswitches I've ever owned were hardwired at the switch end. In fact, the Ampeg Gemini II and the Silvertone 1484 I owned, both had the cable hardwired at the switch and the amp. That was the ultimate convenience. I never misplaced the footswitch! :smiley:
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Steve,
Main reason I was considering a jack on the ft.switch is that I carry all my music gear around in a Bass Pro Shop workout bag. And my homemade tube screamer is in a tupperware box that I kind of like. I was thinking about doing the same thing with the ft. switch and don't think the cord would also fit in the same size tupperware box. And I'm pretty sure the effects box and ft. switch box are the same size?
You know ................... I just kinda got in a way doing that. Sort of like being married and sleeping on a particular side of the bed.
:undecided: :laugh:
Best regards, Jeff
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You don't need the battery either. The voltage coming from the amp will power the LED.
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You don't need the battery either. The voltage coming from the amp will power the LED
The ft.switch box is already wired with a 9volt battery and a resistor to the LED, so I'll just leave it.
Sluckey, ........... IF I do the jack idea on the ft. switch, does this look like I have it drawn right for the relay switching? Just wanting another confirmation, please.
Thanks, Jeff
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>> The ft.switch box is already wired with a 9volt battery and a resistor to the LED, so I'll just leave it.
Then you have to worry about the battery going bad and if you forget to switch the to off the battery continues to drain. Measure the voltage going to the footswitch and adjust the resistor accordingly.
I'm just sayin'
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IF I do the jack idea on the ft. switch, does this look like I have it drawn right for the relay switching?
yes
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You don't need the battery either. The voltage coming from the amp will power the LED.
Could you explain? A drawing would help. THX
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You don't need the battery either. The voltage coming from the amp will power the LED.
Could you explain? A drawing would help. THX
I really want to hear from you on this. I know there are some tricky ways to light up a LED. Hoping you'll share.
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You don't need the battery either. The voltage coming from the amp will power the LED.
Could you explain? A drawing would help. THX
I really want to hear from you on this. I know there are some tricky ways to light up a LED. Hoping you'll share.
I think that this only works with some switching circuits. I've got a footswitch that won't light up at all with a Crate G-40C, but it has the LEDs (and no apparent place for batteries.) Some switching circuits will have a low voltage present on the switch (but high enough to drive a LED) and others just seem to be a gate or base connection switch with not enough voltage or current available to do much of anything but cause the transistor to conduct, or not, depending on the switch's position.
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Guys, please bear with me on this. NOT sure how to hook up the switchcraft switching jack to the relay board?
Is this correct as I have drawn it with the tip, switch and ground (isolated) terminals?
Thanks, Tubenit
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Yes, that will work. Your series connected circuit with switched jack allows the front panel switch to work normally when the footswitch is unplugged from the amp. It also requires the front panel switch to be closed to use the footswitch. This is a logic AND circuit, IOW, panel switch AND footswitch must be on to energize the relay.
Another method would be to just connect the footswitch parallel to the front panel switch via a standard non-switching jack. Now the panel switch must be open for the footswitch to operate, or the footswitch must be open for the panel switch to operate. This is a logic OR circuit, IOW, either panel switch must be on OR footswitch must be on to energize the relay.
See the attached pic for a third option. This option allows the panel switch to function normally when the footswitch is not plugged in. Plugging in the footswitch disables the panel switch and allows the footswitch to function.
You can have any of these variations just by changing the amp chassis footswitch jack wiring.
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Superb INFO !!!!! That's what I was needing. I am going to use your 3rd option which makes the most sense to me.
Thanks, Jeff
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Sorry for the late come back. I can't come up with the LED circuit in the footswitch. I realise now you would need at a ground connection on the footpedal too. If it were possible Sluckey would not have asked me.. He would have known. :embarrassed:
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Not necessarily so. I know I've seen some tricky switching with LED indicators, but it usually involved transistors and/or more than two wires to the footswitch. I thought you had seen something along those lines.
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This is one that I think works, it's a design I'm putting into action, and I'm ASSUMING that with a footswitch wired the way I have pictured it (along side the switching circuit) it SHOULD work, although it should only light when the relays are not energized.
(See attachment for details on what I'm talking about.)