EA Trem - Dumb question, I bet...but here goes...

[Blues_Boy_4096]

Ok, here's the dumb question:

If I use the flashing led on on the PCB (Runoffgroove's layout) as a status indicator, I can use a DPDT switch for the bypass, right?

Thanks

[Auke Haarsma]

from ROG:

"marrstians" reports that the pulsing LED can also serve as a status indicator when using a 3PDT bypass switch. Simply use the third pole of the switch to break the connection between the LED and the collector of Q3 when bypassed.

So, no. you need a 3pdt. Without the breaking of the connection the LED will flash, if the fx is bypassed or not.

[Mark Hammer]

If I use the flashing led on on the PCB (Runoffgroove's layout) as a status indicator, I can use a DPDT switch for the bypass, right?

Yes and no, depending on how you want the pedal to appear.  The flashing LED is part of the tremolo circuit.  That you can see it is simply a (handy) coincidence.  If you use a DPDT stompswitch to have your audio signal completely bypass the tremolo circuit board, the flashing LED will still continue to work, the same way EVERY effect circuit is really still "on" even though you have bypassed it.

Now, if you wanted to cancel the flashing LED when you bypassed the pedal, you *would* need an extra set of contacts to accomplish that.  Similarly, if you wanted to have an "on" indicator for the tremolo pedal, such that you could have a flashing LED of one colour to monitor speed and another nonflashing one to monitor status, that *would* need a 3PDT.  Alternatively, you might be able to get away with using the Millenium Bypass and a DPDT for that.

[Auke Haarsma]

Well phrased Mark!

On a side note, I'm curious on how you'd have the MillBypass using the flashing LED as a status indicator?

[Blues_Boy_4096]

I don't know what I'd do without you guys... 

Thanks a lot!!! 

[Mark Hammer]

Well phrased Mark!

On a side note, I'm curious on how you'd have the MillBypass using the flashing LED as a status indicator?

The MB would have no impact on the flashing LED.  The 100k output volume pot presents a textbook context for using the MB for a 2nd LED to indicate status.

The ROG page ( http://www.runoffgroove.com/eatremolo.html ) indicates that a 3rd set of contacts can be used to interrupt the connection to the flashing LED and thereby serve as a status indicator.  Some might prefer to have the flash rate visible at all times, although battery consumption would be less with a disabled LED during bypass.  If you're wallwarting it, then most usability would involve a separate LFO and status LED, as shown on the ROG site.

BTW, since the flashing LED is set up to simply draw current in response to changes in the LFO transistor, I'm wondering what changes to the 10k resistor might be recommended for changes in LED brightness?

[Auke Haarsma]

Ah ok, I misread you. With two leds I can understand the MB doesn't interfere with the flashing led.

[slacker]

I can't remember what it's called off the top of my head but Joe Davisson had a single transister based circuit for doing true bypass with a DPDT. You can hook that up between 9 volts and the 10k resistor going to the flashing LED then you can use it to turn the LED on and off. This isn't perfect as it turns the whole LFO off when bypassed so it can take a fraction of a second to start sweeping after you engage the effect.