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Slow Loris mod

Started by Doctorjello, October 29, 2016, 09:59:05 PM

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Doctorjello

Good evening all-
I just fired up my SL and it sounds great. Of course it's late and everyone's sleeping, so my test was really just a function check but still. I love it. I'm one step closer to the Rats Nest I'm building.
Now I have a question about a mod. The SPDT in there currently just alternates between D1/2 and D3/4. Is there a way to remove both and have the opamp clipping as an option? Either by swapping out for an On/off/on switch or by adding a second SPDT and basically cutting out the middle lug of the original? Thanks!!

JackSkellington

You should link the schematic or the PCB layout.
«Just because I cannot see it doesn't mean I can't believe it»

m-Kresol

using a On/Off/On schould do the trick
I build pedals to hide my lousy playing.

My projects are labeled Quantum Effects. My shared OSH park projects: https://oshpark.com/profiles/m-Kresol
My build docs and tutorials

Doctorjello

I guess I should have worded that differently. I didn't post the schem since it's one of Madbeans builds. Sorry.

I knew the on/off/on would work, as that is what I usually do. And that's what I did tonight. It's awesome. You know you have a solid build when you start writing riffs the second you fire it up!!

But for reference- if I had to use a SPDT on/on, could I interrupt the signal and get to just the opamp with an additional SPDT? My vision maybe jumping the center lug out to the kill switch and then back. When the switch is on, the diode selector goes between the two choices and when it's off you've basically disabled the switch, so it goes to the opamp. I feel like I have a wire missing. I haven't played with it yet.
Of course the +\-\+ is the easiest. But that's not always the best!

m-Kresol

I don't quite understan what you mean by "it goes to the opamp". If you use a regular SPDT On/Off/On, you'll obviously have the diodes in the circuit in the On positions. In Off you basically just lift the GND and thus take the diodes out of the circuit (if C14 is in, D1 and D2 might be considered still "in", as the AC signal will pass through it). The signal will always go through the opamp obviously and the opamp clipping will always be there but covered up by the stronger diode clipping.

Or did you want to bypass everything after the opamp including the cut pot etc?
I build pedals to hide my lousy playing.

My projects are labeled Quantum Effects. My shared OSH park projects: https://oshpark.com/profiles/m-Kresol
My build docs and tutorials

midwayfair

I also can't figure out what you want to do here.

The op amp clips because you're asking it for a crap load of gain (anything from 1x to about 200x).

The diodes clip when they're connected to the signal path and ground.

The clipping switch just disconnects one set of diodes from ground and switches to the other.

Are you maybe asking for a switched setting that would lift the diodes but dime the gain control?

Doctorjello

My apologies. I've been up late this week.
You are correct about my intentions. I've installed an on/off/on switch, which in one position clips D1/2 and in the other clips D4/5. In the center (off position) it removes both sets of diodes and clips the opamp, a sound I'm fond of in other similar builds. I guess my main question was if there was another way to accomplish the same result but by using an additional switch. I recognize that it would be a less efficient use of time and parts, it was just a necessity I had come across when I only had on/on switches and no on/off/on switches in my bin. That's since been rectified. What would be the correct way to wire an additional on/on switch to effectively "lift" both sets of clipping diodes and send signal straight to the chip?

thesmokingman

first switch either sends signal to the second or not at all. bob's your uncle from there
once upon a time I was Tornado Alley FX

m-Kresol

If you had to use 2 on/on switches I'd do the following:
First one is wired to either side of the of the clipping diodes, ie. D1&D2 and D3&D4. The centre lug goes to the other switch's centre lug, which is wired as SPST switch. one of the outer lugs of this switch is wired to GND.

this way, the first switch would choose between the two diode clipping options, while the other would lift both.
I build pedals to hide my lousy playing.

My projects are labeled Quantum Effects. My shared OSH park projects: https://oshpark.com/profiles/m-Kresol
My build docs and tutorials

midwayfair

#9
I am a derp.

thesmokingman

I guess if I add anything to this beyond this point, its that I guess if you like the no diodes sound go for it ... how good or bad it sounds will come down to whether you've used the lm308 and feedback filter/gain arrangement of the rat or if you went modified like a fat rat/ruetz mod/lube mod etc ... my vote in this instance would be for classic rat values.
once upon a time I was Tornado Alley FX

Doctorjello