What ic? for this loop/bypass vero

DonB · May 24, 2011, 05:02:22 PM

I found this vero for a loop/bypass with trails switch. But have no idea what the ic looking thing is?

Ice-9 · May 24, 2011, 05:08:55 PM

Looks like it's probaly and dual op amp.

ie
pin 4 ground
pin 8 +v
Pin 1 + 2 are tied together ( 1 op amp output feedback to inverting input pin2)
pin 3 has an input through C1
Pin 7 has output through C5

try a TL072 or a 4558 or any standard 8 pin dual op amp that has same pinouts as TL072

DonB · May 25, 2011, 03:54:55 AM

OK. I do have some 4558's here.

slacker · May 25, 2011, 08:19:07 AM

Yeah pretty much any dual opamp will work in it.

dewey decibel · May 25, 2011, 10:18:40 PM

Was going to start a new thread but saw this one, hope you don't mind the hijack.

I need to build one of these and have some questions. First are there any issues with phase when the two signals are summed together? How about popping when switching? Lastly I take it this loop stays active all the time, in effect buffering the signal?

Thanks in advance!

slacker · May 26, 2011, 08:00:08 AM

The signals are summed in phase, so there's no issue there. In any case, the only mix you get is dry with the tails from whatever is in the loop, as this is mostly likely to be a delayed signal of some sort the phase isn't relevant. The overall phase of the output is inverted compared to the input, but unless you're mixing this with other things in parallel that's not a problem.

In theory, there should be no switch popping and my build had no problems, but this was only a quick test to make sure the idea worked.

Yes, the loop is active all the time so it buffers the dry signal.

Hope that helps.

dewey decibel · May 27, 2011, 04:13:09 PM

Thanks, going to give this a try in the next couple weeks, will report back. I saw you had another version with a feedback loop which sounded interesting, but all I really need right now is the trails part of the equation.

DonB · May 30, 2011, 04:24:02 PM

I want to combine this with a boost pedal (in one). So when i press the switch for the boost the circuit is active (turning on my delay). How do i go about wiring the 2 together with an LED?

DonB · June 05, 2011, 06:52:03 AM

Can ceramic caps be used instead of poly film/greenies?

I have 10n and 100n in ceramics but not greenies

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What ic? for this loop/bypass vero