Logan Sound - Wah Anti-Wah

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Logan Sound - Wah Anti-Wah

Postby phishmarisol » 13 Dec 2007, 21:50

Anyone know if this is an original design? I could have sworn I saw a kit for it somewhere but no idea where.

http://www.logansoundinc.com/Home_Page.html
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Postby Bernardduur » 13 Dec 2007, 21:52

When I think about wah / antiwah

I think about this Craig Anderton circuit

maybe the same :)
Last edited by Bernardduur on 13 Dec 2007, 22:11, edited 1 time in total.
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Postby analogguru » 13 Dec 2007, 21:55

It contains two analog wah filters each set to two different frequency ranges. One wah filter is centered on the low frequency range of the guitar and other wah filter is centered on the high frequency range.


compare it with the EH bassballs....

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Postby The Rotagilla » 13 Dec 2007, 22:00

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Postby flood » 15 Dec 2007, 17:51

judging from the description, it's a 1:1 copy. i built the wah antiwah a long time ago, and it really didn't do much for me - i must admit however that i didn't realize it's full potential then. i'm thinking about building it again and using it somewhere before my distortion chain. maybe a low-gain booster circuit following the anderton design would be good too.

$199???? highway $"%&ng robbery

EDIT: i didn't scroll all the way to the bottom of the page. there seem to be more parts in there than the schematic would let me imagine... maybe he isn't using a dual op-amp, but single op-amp types. otherwise, the description seems to fit perfectly... any ideas?
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Postby analogguru » 15 Dec 2007, 18:43

He IS using single op-amps...

additional components are 2 resistors near the noninverting input of every op-amp to form a bias divider cause he is running the unit from single supply.

also coupling capacitors at the output - seem to be polyester, no electrolytics.

A 3-terminal voltage regulator also seems to be involved... nobody knows why...

And on each side of the potentiometer is an additional resistor in series...

thats all...

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Postby flood » 16 Dec 2007, 12:25

:D
ein analog guru
es gibt nur einen analog guru
ein analog goooo rooo
es gibt nur einen analog guru


thanks! maybe i will give this one a second chance sometime. it did sound quite funky on my yamaha electronic drums...
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Postby kaz » 18 Dec 2007, 09:51

Hello!!

I think it to be reliable with schematic.
Is it a correct answer:roll:
http://i268.photobucket.com/albums/jj21/stomper_fx/LoganSoundWahAnti-Wah.jpg
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Postby analogguru » 18 Dec 2007, 10:50

The schematic above reflects what the unit appears to me....

I have to disagree with one thing: C3

I believe that C3 exists twice:
one after R4 and one after R10 and the two signals are mixed after these two caps.

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Postby kaz » 19 Dec 2007, 03:30

Thank you, analogguru!!

Because these two caps are large, whether the jumper you thought.
As for these two caps you think that it is what?
http://i268.photobucket.com/albums/jj21/stomper_fx/antiwah_pcb.jpg
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Postby analogguru » 19 Dec 2007, 07:13

As for these two caps you think that it is what?


As it is shown in the pcb: 2 capacitors 0,1 µF.

In the schematic is only 1..... :?

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Postby flood » 19 Dec 2007, 23:49

noob question: is there any specific advantage from using two single opamps instead of one dual? i can't for the life of me figure out why...
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Re: Logan Sound - Wah Anti-Wah

Postby puppiesonacid » 15 Apr 2008, 12:35

does anyone have shots of the component side of this pedal? and am I right to assume that the submitted schematic is not 100%? thats what I gathered from reading through the posts, but I'm not sure.


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Re: Logan Sound - Wah Anti-Wah

Postby Jaicen » 15 Apr 2008, 20:03

Perhaps if he's using 741's, the slew rate or frequency response are useful to the sound??
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RE: Logan Sound - Wah Anti-wah

Postby puppiesonacid » 16 Apr 2008, 01:19

could the Q-zone be modded to get the same sound or does it already kinda do that Brian May thing? i've never heard a qZone before.
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Re: Logan Sound - Wah Anti-Wah

Postby puppiesonacid » 22 Apr 2008, 18:31

[smilie=bump.gif]
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Re: Logan Sound - Wah Anti-Wah

Postby puppiesonacid » 30 Apr 2008, 15:25

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Re: Logan Sound - Wah Anti-Wah

Postby soggybag » 01 May 2008, 17:41

Is there any reason that you might use two single op-amps each with their own Vb for this? Seems you could make it all with a sinlg op-amp and one voltage divider for Vb.

I don't quite get the wah action. It seems there are two filter with different caps to produce a different filter range. There is sort of a passive mixer at the input of each filter. I don't get how this mixing changes the sweep range. To me it looks more like the filters are fixed and the mix is determining how much input signal gets to each filter?
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Re: Logan Sound - Wah Anti-Wah

Postby puppiesonacid » 02 May 2008, 12:18

yeah I'm trying to figure that one out myself soggy. From what I understand its two opposing wah filters tuned to seperate frequencies. As the pot is turned is sweeps between the two, one going up one going down in and opposing but equal fashion. I've tried hook up two wah's in series with opposite sweeps, but it does not produce the "Brian May" kinda lead sound. Maybe it needs more specific tuning to hit the right midrange peak but the second opamp throws me off. If Andertons pedal produced a similar sound as the Logon Sound Wah-Anti-Wah then why add the second filter? It would make sense to me if the pot was dual ganged and one was wired for reverse taper and sweep opposite but equal to the other filter sweep but Idk.

I perfed one up following the anderton schematic a couple months ago using a TLO72 but I couldn't get any sound through but rather only could hear the "panning" between two sides as I turned the pot. I really want to build one of these because I dig the soundclip from the Logon Sound site but I absolutely refuse to pay 200$ for it.

I'm going to try out a layout based on AG's PC board analysis and plug and play with cap values. I'll let you all know how it goes. If you study it real hard you can see that has sort of a parallel circuit going on. The artwork kinda repeats itself on the pcb.


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Re: Logan Sound - Wah Anti-Wah

Postby flood » 09 May 2008, 18:27

hey there puppiesonacid,

i have built this circuit, albeit a very long time ago. it didn't do much for my guitar - i think i should have tried putting a buffer before it, but sounded kinda cool with a drum machine.

when this thread was opened, i revisited it and simulated it in circuit maker. changing the cap cvalues, or misbalancing them makes a huge difference to Q. i got some very interesting waveforms.

i will probably BB this circuit soon, with an added distortion stage to follow it. i actually came up with a layout for it in eagle - wah, distortion, volume and two 6 position switches but lost it due to data corruption. probably better that way, since i tend to make layouts for things whose function i'm unsure of.

will pop out the ol' breadboard this week and see what i can find...
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