madbeanpedals::forum

Projects => Tech Help - Etcher's Paradise => Topic started by: selfdestroyer on February 22, 2016, 04:18:55 AM

Title: Gravity Wave (Verified)
Post by: selfdestroyer on February 22, 2016, 04:18:55 AM
This is a fun pedal and will get boxed up for sure.

I was battling with another build of mine and decided to populate this to clear the mind a bit and next thing I knew it, I was firing it up. Played with it for about 45-hour and it was fun. From subtle to extreme chorus effect.

(http://music.codydeschenes.com/wp-content/uploads/2016/02/gravitywave.jpg)

I also took my voltages to share.
Powersource: 9.1v

IC1:

1 4.3v
2 4.3v
3 3.9v
4 0
5 4.3v
6 4.3v
7 4.3v
8 8.7v

IC2:

1 4.9v
2 2.4v
3 0
4 0
5 2.7v
6 2.4v
7 0.8v
8 0.8v
9 2.4v
10 2.4v
11 2.4v
12 2.4v
13 2.4v
14 2.4v
15 2.4v
16 2.4v

IC3:

1 Varied
2 4.2v
3 Varied
4 8.7v
5 Varied
6 Varied
7 Varied
9 Varied
10 4.3v
11 0
12 4.3v
13 4.3v
14 Varied

IC4:

1 4.3v
2 4.3v
3 4.3v
4 0
5 4.3v
6 4.3v
7 4.3v
8 8.7

Edit: Fixed wrong voltages

Cody
Title: Re: Gravity Wave (Verified)
Post by: Alex on February 22, 2016, 06:32:10 AM
Hi Cody.
Is your Dimension pot working properly?
Some people built it on vero and had some problems:
http://tagboardeffects.blogspot.fr/2016/02/madbean-gravity-wave-earthquaker.html
Title: Re: Gravity Wave (Verified)
Post by: Alex on February 22, 2016, 06:44:04 AM
There's a writing mistake in you IC3 voltages.
14 pins and Pin 11 should be 0.
Title: Re: Gravity Wave (Verified)
Post by: jimilee on February 22, 2016, 09:47:00 AM
Well that's cool.


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Title: Re: Gravity Wave (Verified)
Post by: alparent on February 22, 2016, 10:03:57 AM
That's good news.
Glad others are also verifying these great projects.
Title: Re: Gravity Wave (Verified)
Post by: selfdestroyer on February 22, 2016, 11:16:53 AM
Hi Cody.
Is your Dimension pot working properly?
Some people built it on vero and had some problems:
http://tagboardeffects.blogspot.fr/2016/02/madbean-gravity-wave-earthquaker.html

Thats weird, I am definitely not getting any motor boating on the Dim pot. I will hook it up again tonight and play around with it. To be honest, I just watched the PGS video and I was able to achieve some of the sounds right off the bat so I called it good.

There's a writing mistake in you IC3 voltages.
14 pins and Pin 11 should be 0.

I checked my notes this morning and that was no misprint. I will trace it out tonight and see if it is in fact wrong.

Thanks for the info.

Cody
Title: Re: Gravity Wave (Verified)
Post by: selfdestroyer on February 22, 2016, 11:23:24 AM
I will add this for reference:

Rate: Sets the speed of the LFO. The miniature LED will show the tempo even in bypass mode.

Shape: From soft triangle through hard square wave.

Dimension: Adds a slight slap-back at low levels, reverb-like ambiance at mid levels and an echo-resonance at max.

Intensity: How much the LFO modulates the delay time.

Animate: How far the pitch shifted signal swings, lower levels equals a tighter and more focused shift ŕ la traditional chorus. As you increase the control a more wild and animated pitch shift begins to emerge.

Depth: How much modulated signal is blended in with the dry signal.

Cody
Title: Re: Gravity Wave (Verified)
Post by: madbean on February 22, 2016, 07:17:38 PM
As mentioned before, pin11 of IC3 should definitely be 0v. It's connected to the ground plane.

Thanks for the update on verification :)
Title: Re: Gravity Wave (Verified)
Post by: selfdestroyer on February 23, 2016, 02:44:51 AM
As mentioned before, pin11 of IC3 should definitely be 0v. It's connected to the ground plane.

Thanks for the update on verification :)

ok, I rechecked my voltages and I definitely have 0v on pin 11 of IC3. I just wrote it down wrong. LOL

The dimension pot will oscillate just over 50% like a feedback pot on a delay pedal. Some tweaking might be in order.

This thing sounds great and will be boxed soon.

Cody
Title: Re: Gravity Wave (Verified)
Post by: jimilee on February 23, 2016, 10:08:04 AM
Why is this not in the store??? I need to have one.


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Title: Re: Gravity Wave (Verified)
Post by: alparent on February 23, 2016, 10:31:33 AM
There is enought etchers here to make you one. Just ask and make an arrangement.
I need to etch more boards (now that Brian added some projects) I could whip one up for you. (If you're not in a big rush.)
Title: Re: Gravity Wave (Verified)
Post by: jimilee on February 23, 2016, 11:41:21 AM

There is enought etchers here to make you one. Just ask and make an arrangement.
I need to etch more boards (now that Brian added some projects) I could whip one up for you. (If you're not in a big rush.)
That would be lovely, thank you. No rush. I'd  learn if I didn't have to drill the boards.


Sent from my iPhone using Tapatalk
Title: Re: Gravity Wave (Verified)
Post by: Loe on February 23, 2016, 12:08:39 PM
I feel the same, Jimilee. I love etching my own boards but the drilling makes me want to tear my hair out. I just showed my girlfriend how to do it. Let's see how many she does for me before she realizes how tedious it is.  ;D
Title: Re: Gravity Wave (Verified)
Post by: alparent on February 23, 2016, 12:21:38 PM
What are you using? With the right tools......it takes the time it takes......but it's not that bad.
Title: Re: Gravity Wave (Verified)
Post by: dan.schumaker on February 24, 2016, 09:33:56 AM
I feel the same, Jimilee. I love etching my own boards but the drilling makes me want to tear my hair out. I just showed my girlfriend how to do it. Let's see how many she does for me before she realizes how tedious it is.  ;D

I feel the opposite.  I've never been able to get a good etch, but after getting a dremel drill press, drilling holes is no issue for me.
Title: Re: Gravity Wave (Verified)
Post by: gordo on February 24, 2016, 11:59:05 AM
Yeah ditto on that.  The drilling is a breeze.  I use the aquarium air pump from my etching rig to blow a stream of air across the board to get rid of the little piles of board material.  Not at all necessary but one of those little tricks to make the process less annoying.  I bought a bunch of drill bits from a hobby shop that were cheap but don't last all that long.  The only part of the process I hate is cutting the pcb board itself and having to deal with FeCl, which I invariably manage to get on something it's not supposed to be on.
Title: Re: Gravity Wave (Verified)
Post by: Loe on February 24, 2016, 12:36:47 PM
What are you using? With the right tools......it takes the time it takes......but it's not that bad.

I use the Dremel drill press, along with a Dirt Devil Scorpion hand vac to suck up the toxic dust. I'm nearly blind in my left eye so it's a real PITA for me to look at all those tiny dots. Eventually I will probably try to figure out a way to mount the magnifying glass from my third hand tool onto the Dremel drill press... Or just buy a new left eye.  ;)
Title: Re: Gravity Wave (Verified)
Post by: alparent on February 24, 2016, 12:37:27 PM
Aquarium pump! Nifty, never occurred to me.
I have air blowing but from my big air compressor. Drill my boards with ear plugs because of the compressor's noise (and can't do it when kids are sleeping) But this air pump trick is great.
Title: Re: Gravity Wave (Verified)
Post by: alparent on February 24, 2016, 12:45:44 PM
What are you using? With the right tools......it takes the time it takes......but it's not that bad.

I use the Dremel drill press, along with a Dirt Devil Scorpion hand vac to suck up the toxic dust. I'm nearly blind in my left eye so it's a real PITA for me to look at all those tiny dots. Eventually I will probably try to figure out a way to mount the magnifying glass from my third hand tool onto the Dremel drill press... Or just buy a new left eye.  ;)

I'm getting older and I couldn't do electronics if I didn't have these.
http://www.ebay.ca/itm/NEW-Headband-Headset-10-Magnifier-Magnifying-Glass-Lens-Loupe-with-LED-Light-/281873505012?hash=item41a0f85af4:g:-IIAAOSwNphWXxkj (http://www.ebay.ca/itm/NEW-Headband-Headset-10-Magnifier-Magnifying-Glass-Lens-Loupe-with-LED-Light-/281873505012?hash=item41a0f85af4:g:-IIAAOSwNphWXxkj)

Drilling, soldering, reading inscriptions and parts.......love them!
Title: Re: Gravity Wave (Verified)
Post by: thesmokingman on February 26, 2016, 12:09:45 PM
definitely going to see about getting one of these from someone ... pedal sounds pretty epic
Title: Re: Gravity Wave (Verified)
Post by: Droogie on February 26, 2016, 12:13:25 PM
definitely going to see about getting one of these from someone ... pedal sounds pretty epic

Keefe (Haberdasher) has the goods. Got this and four others from him and they are excellent!
Title: Re: Gravity Wave (Verified)
Post by: Droogie on February 28, 2016, 07:43:17 PM
Just fired this one up and the chorus/vibe is excellent! I am having issues with the Dimension pot also—feeds back at 25% of the rotation. I'll check my voltages, parts etc. I checked the demo for the original to see what the behavior is, and really it just adds a bit of slapback echo with some increase in feedback (to my ears). I could live without the dimension since the chorus is really sweet! Nice action on the shape control and Animation.
Title: Re: Gravity Wave (Verified)
Post by: Scruffie on February 28, 2016, 07:48:49 PM
A Log taper might be better for the dimension pot...
Title: Re: Gravity Wave (Verified)
Post by: madbean on February 28, 2016, 08:10:17 PM
Increasing R10 should help with the Dimension pot.
Title: Re: Gravity Wave (Verified)
Post by: Droogie on February 28, 2016, 08:21:39 PM
R10 to 18k was mentioned on the Tagboard thread referenced upstream. I'll try it out!
Title: Re: Gravity Wave (Verified)
Post by: Droogie on March 05, 2016, 09:38:42 AM
So I tried various values for R10 and no love (18k, 33k, 47k, 100k). I get a continuous tone/feedback sound (not delay fb, should have made that more obvious before). If I go as high as 100k, the tone doesn't happen, but no slapback as heard in demos for the original pedal either. I also tried raising the value of the Dimension pot to 50k but same results.

I checked values for all other parts involved and they're correct; no bridges, etc. Not to say that I couldn't have missed something...

Any thoughts of next steps?
Title: Re: Gravity Wave (Verified)
Post by: Midgardius on March 20, 2016, 01:38:33 PM
I have same problem with DIM pot to...
I tryed to increase R10 value, but it not help. Maybe something more needs chenges? Maybe it need to cut low freq around the DIM pot, course its sound like endless feedback in low freq?
Title: Re: Gravity Wave (Verified)
Post by: bigzed on March 26, 2016, 12:03:05 PM
Hi Guys, I'm from the UK and love building pedals especially challenging ones with a worthwhile outcome and this is certainly one of them!

I had all the defects described in this forum regarding the Dim pot. I eventually got around the problem with the help from Ciaran from Guitar FX Layouts and this is what I did..

I changed the 5k Dim pot to a 50k, R10 8K2 changed to a 120K (any lower value and the whining was still present). On the fly I also added a 10k resistor from pin 2 of the opamp to + leg of a 1uf Cap and - leg to the Dim 3 lug row..bit unsightly but it seems to work. I do have a small amount of controllable reverb on the Dim but the whining and motor boating have gone and the pedal works and sounds great. I know this is a big change from the Gravity Wave schematic but I can't see how else to overcome the issues.
If anyone ones else finds a better solution I'd be very interested?
Cheers
Bill
Title: Re: Gravity Wave (Verified)
Post by: madbean on March 26, 2016, 12:29:53 PM
Might be better to reduce R7/R8 to 10k then.
Title: Re: Gravity Wave (Verified)
Post by: bigzed on March 26, 2016, 01:03:04 PM
Reducing the R7/R8 values would that alone solve the Dim pot issues?
Title: Re: Gravity Wave (Verified)
Post by: madbean on March 26, 2016, 02:01:02 PM
Well I don't know. But, it would reduce the gain of that output from the PT2399 which might help a lot. Or, not!
Title: Re: Gravity Wave (Verified)
Post by: Scruffie on March 26, 2016, 02:18:55 PM
Actually, reducing them would change the cut off of the multiple feedback filter and increase gain.

Are we sure C9 is 330n? 33n makes more sense to me... also seems like there should be a cap to ground from R3.

So looking at the schematic, the input goes through an MPF in to the PT2399 and then the wet output goes straight to the output unfiltered and the feedback (or dimension) goes through another filter using the other PT2399 opamp before being fed back in to the PT2399 input.

Anyway, increasing R9 should limit the feedback, if you increase R10 you're adjusting other stuff too.
Title: Re: Gravity Wave (Verified)
Post by: bigzed on March 26, 2016, 02:35:43 PM
I wondered about the C9 too! You are correct about R10 changing other stuff, that's why the mod using a 10k res and 1uf cap from pin 2 of the opamp to lug 3 of the dim was required and put the reverb back.
Title: Re: Gravity Wave (Verified)
Post by: madbean on March 26, 2016, 03:04:00 PM
Actually, reducing them would change the cut off of the multiple feedback filter and increase gain.

Are we sure C9 is 330n? 33n makes more sense to me... also seems like there should be a cap to ground from R3.

So looking at the schematic, the input goes through an MPF in to the PT2399 and then the wet output goes straight to the output unfiltered and the feedback (or dimension) goes through another filter using the other PT2399 opamp before being fed back in to the PT2399 input.

Anyway, increasing R9 should limit the feedback, if you increase R10 you're adjusting other stuff too.

Reducing R7 increases the gain of the MFF, but reducing R8 decreases the output at pin 14. My thinking here was series resistance at R10 was not giving the right result so let's have less output at LPF-2 (although it does change the whole thing). But, you are probably right - just leave everything as is and make R9 bigger. I should really etch this board and build it.

I'll have to double check on that 330n cap.
Title: Re: Gravity Wave (Verified)
Post by: madbean on March 26, 2016, 03:09:20 PM
Pretty sure 330n is right. It's on the trace schematic I have and if you look at gut shots of the SM, you'll see a huge Panasonic cap right around pin9 of the PT2399 which could only be that size.

(http://files.effectsdatabase.com/gear/pics/earthquaker_seamachine_002.jpg)
Title: Re: Gravity Wave (Verified)
Post by: Scruffie on March 26, 2016, 03:12:35 PM
Could that huge cap not be the 470n from the LFO?
Title: Re: Gravity Wave (Verified)
Post by: bigzed on March 28, 2016, 08:20:56 AM
Ok..so i replaced all the changes I made 50k back to 5k pot, 120k to 8k2 R10 and removed the link 10k resistor and 1uf pot..

So back to square 1 and the whining is back as it was to begin with. I then changed the 1k R9 to a 10K and the whining stopped but the reverb was weak so I also changed  the 33K R7/8 resistors to 10k each and that seemed to increased the reverb. I think now it is exactly the same as the video demo. So with these changes I'd consider this Verified!
Title: Re: Gravity Wave (Verified)
Post by: Scruffie on March 28, 2016, 08:32:23 AM
See, I think that whining is the MFF oscillating as the Q is too high, but if it was 33nF, it'd make much more sense... care to try if that works without having to change resistor values?
Title: Re: Gravity Wave (Verified)
Post by: bigzed on March 28, 2016, 09:20:20 AM
I put it all back again and changed the cap from 330n to 33n but It still needs the 10K resistor for R9 to stop the whining! But changing the 330n cap to 33n really increases the reverb....a lot!!!

So to recap change R9 to 10k and the 330n cap to 33n leave everything else as is and it really works well. Well done Scruffie!
Title: Re: Gravity Wave (Verified)
Post by: bigzed on March 28, 2016, 09:32:59 AM
Or to make it easier....remove the 0 from C9 and put it on R9!!!
Title: Re: Gravity Wave (Verified)
Post by: Scruffie on March 28, 2016, 10:11:40 AM
Well, I can't say if that's how it's meant to be but if it works, great!
Title: Re: Gravity Wave (Verified)
Post by: selfdestroyer on March 29, 2016, 10:35:53 AM
I wanted to add that C9 to 33n and R9 to 10K worked great for me.

Also, sorry I jumped the gun on verifying this build. I honestly thought the feedback was normal due to the slapback controls. Its all sorted now and I really love this effect.

Cody
Title: Re: Gravity Wave (Verified)
Post by: blearyeyes on March 29, 2016, 06:52:41 PM
Cool thread.. Cool Pedal.
Title: Re: Gravity Wave (Verified)
Post by: djentleman843 on April 15, 2016, 03:49:22 PM
I've applied the fix listed here and while it kills the whine, it also makes that control so subtle its pretty useless. I would almost rather have the whine after 30% but still get that cool echo/verb.

Also- is there a way to slow it down... seems to be extremely fast even at slow settings.
Title: Re: Gravity Wave (Verified)
Post by: Scruffie on April 15, 2016, 03:53:09 PM
I can't comment on how the mod sounds, so someone else will have to confirm if it makes it too subtle or if there's perhaps an error on your build.

Slowing down the LFO is easy though, just make C20 a 1uF NP.
Title: Re: Gravity Wave (Verified)
Post by: bigzed on April 22, 2016, 11:19:44 AM
I am definitely getting slap back on the Dimension control with this mod as per the demo.
Title: Re: Gravity Wave (Verified)
Post by: bigzed on April 24, 2016, 06:04:38 AM
I also put a 4.7uf for C20 (+ side to pin 12 on the lm324) Slows it down to a more manageable level.
Title: Re: Gravity Wave (Verified)
Post by: wainer said on June 04, 2016, 04:03:01 PM
What would that VC entry ? this layout? tanks
Title: Re: Gravity Wave (Verified)
Post by: mauzau on June 05, 2016, 11:47:13 AM
I changed the values suggested by Bigzed and it sound like the demo watched on you tube.
Thank you Bigzed!
Title: Re: Gravity Wave (Verified)
Post by: impycat1 on June 17, 2016, 11:45:58 AM
Changed the recommended components this evening. Replaced C20 with a 4.7uf non polar as I had a few in stock. Works perfectly now. 

Thanks Bigzed.
Title: Re: Gravity Wave (Verified)
Post by: stringsthings on July 01, 2016, 11:41:10 AM
Just finished my build.   This pedal is very versatile.  I'm still surprised by the innovative uses of the PT2399 chip.
Thanks for the project Bean!  And thanks to all those who found the optimum parts substitutions.

I also used a 33nf for C9, 10k for R9, and a 4.7uF for C20.  For C20, the + side connects to pin 13 of IC3/LM324.
Title: Re: Gravity Wave (Verified)
Post by: Alex on July 17, 2016, 04:59:49 AM
Chris has checked his original pedal and posted the corrections on https://tagboardeffects.blogspot.fr/2016/02/madbean-gravity-wave-earthquaker.html
The only difference between Brian's schematic and the original is C9 (not 330n but 3n3).
R9 should be 1K.
Title: Re: Gravity Wave (Verified)
Post by: /)an/)an on October 01, 2016, 11:57:48 PM
Hi!

Im fairly new and was wondering if any etchers would be able to etch me a pcb of the gravity wave? How much eould you charge etc? And to ship to new zealand?

Thanks very much!

D
Title: Re: Gravity Wave (Verified)
Post by: lars-musik on December 13, 2016, 07:21:15 AM
Hello madbeaners,

I am planning to build a Gravity Wave for Bass use. Would you recommend a dedicated blend feature or could you estimate the bass loss if the circuit is kept as it is and the "Depth" knob does all the blending work?

Thanks for your help, Lars
Title: Re: Gravity Wave (Verified)
Post by: plush on January 27, 2017, 01:54:10 AM
Hi guys,

Any ideas how to get rid of lfo ticking noise? It persists even when the pedal is turned off.

Thanks.
Title: Re: Gravity Wave (Verified)
Post by: Scruffie on January 27, 2017, 04:59:48 AM
Hello madbeaners,

I am planning to build a Gravity Wave for Bass use. Would you recommend a dedicated blend feature or could you estimate the bass loss if the circuit is kept as it is and the "Depth" knob does all the blending work?

Thanks for your help, Lars
I should think it'd be fine as designed for bass, the signal caps are quite large already and dry signal is always mixed in.

Perhaps increase C1 to 220nF.

Hi guys,

Any ideas how to get rid of lfo ticking noise? It persists even when the pedal is turned off.

Thanks.

How neat is your wiring? If it's happening in bypass that suggests to me your rate pot or other LFO wires might be passing by something carrying signal.

But, you can try adding a large electro (22-100u) across the 324 power pins as close to the actual chip as physically possible, positive to pin 4, negative to pin 11.
Title: Re: Gravity Wave (Verified)
Post by: plush on January 30, 2017, 03:40:25 PM

How neat is your wiring? If it's happening in bypass that suggests to me your rate pot or other LFO wires might be passing by something carrying signal.

But, you can try adding a large electro (22-100u) across the 324 power pins as close to the actual chip as physically possible, positive to pin 4, negative to pin 11.

I don't think there is something with my wiring.
There is also no unwiped rosin or solder bridges or ground loops and etc.

I simply plug the pedal into my amp and switch it to high gain channel and lfo ticking appears. When i switch it to clean channel, lfo ticking disappears.

This made me think that there is smth with my amp (mark V:25). To check it, I plugged the pedal into my slo100 and experienced the same thing.

I've also tried to put some kind of overdrive or dist after gravity wave and then plug it into my clean amp. As expected, lfo ticking appeared as soon as the drive pedal was engaged. Fun thing, there is no ticking when drive pedal is placed before the chorus.

I tried to power the pedal with both 9v battery and isolated power supplies (trex chameleon, cioks coikolate) with the same results.

Unfortunately, capacitor trick also did not work.

Sorry for my english.

Crappy gutshot attached:
(http://i.imgur.com/bckHh6H.jpg)
Title: Re: Gravity Wave (Verified)
Post by: Boba7 on February 01, 2017, 01:18:10 AM
Did you try moving the depth and rate pot away from right under the jacks? Could make a difference I think.
Title: Re: Gravity Wave (Verified)
Post by: plush on February 01, 2017, 02:25:43 AM
Could make a difference I think.

Why should it? The pots are screened. They can't be a source of interference.
Title: Re: Gravity Wave (Verified)
Post by: Boba7 on February 01, 2017, 04:23:19 AM
A phaser I built some time ago had this problem. I think it was the rate pot that was too close to the input or output jack, causing ticking. Can't remember exactly.

I could be totally wrong of course! But it wouldnt be difficult to just take out the rate pot of under the jack and see if the ticking goes away.

And the dust caps protect from contact, but won't do anything again lfo ticking or other interferences.

Hope you get rid of the ticking!!
Title: Re: Gravity Wave (Verified)
Post by: plush on February 01, 2017, 04:51:14 AM
But it wouldnt be difficult to just take out the rate pot of under the jack and see if the ticking goes away.

And the dust caps protect from contact, but won't do anything again lfo ticking or other interferences.

Hope you get rid of the ticking!!

Even knowing that it won't help, I took everything out. Nothing has changed.

Dust caps... I was not talking about dust caps, but about the potentiometer body. It is made of metal and acts as a shield when connected to the grounded enclosure.

I appreciate your willing to help.
Thanks.
Title: Re: Gravity Wave (Verified)
Post by: Boba7 on February 01, 2017, 05:17:29 AM
But it wouldnt be difficult to just take out the rate pot of under the jack and see if the ticking goes away.

And the dust caps protect from contact, but won't do anything again lfo ticking or other interferences.

Hope you get rid of the ticking!!

Even knowing that it won't help, I took everything out. Nothing has changed.

Dust caps... I was not talking about dust caps, but about the potentiometer body. It is made of metal and acts as a shield when connected to the grounded enclosure.


Oh yeah you're right... sorry I couldn't help much. Did you try a tl062 or tl022 instead of 072 for the lfo?
Title: Re: Gravity Wave (Verified)
Post by: plush on February 01, 2017, 07:14:30 AM

Oh yeah you're right... sorry I couldn't help much. Did you try a tl062 or tl022 instead of 072 for the lfo?

It uses LM324 for the LFO, not 072s.
I've tried 3 different 324, with no success.
Title: Re: Gravity Wave (Verified)
Post by: Boba7 on February 01, 2017, 07:24:33 AM
It uses LM324 for the LFO, not 072s.
I've tried 3 different 324, with no success.

Oups sorry again then!
Title: Re: Gravity Wave (Verified)
Post by: lars-musik on February 01, 2017, 10:12:01 AM
I should think it'd be fine as designed for bass, the signal caps are quite large already and dry signal is always mixed in.

Perhaps increase C1 to 220nF.

pin 4, negative to pin 11.

Thanks very much for your input Scruffie. I realized that there is not much bass loss to be expected from the filtering in the circuit. However, *I think* the depth pot determines the amount of dry signal mixed to the delayed one, and thus creating the chorus sound .If I dial in an especially crazy sound yet want it to be more subtle or less deep, a dry-blend feature is helpful. I finished my built and included this feature and really like the result.

(http://i1244.photobucket.com/albums/gg578/lars-musik/Sea_C_fertig.jpg)
Title: Re: Gravity Wave (Verified)
Post by: Scruffie on February 01, 2017, 10:28:34 AM
The depth pot is actually a wet level control, but if separate wet and dry controls work for you that's the main thing.

I just noticed something else that I think might be a tracing mistake, C19, usually a cap like that would be found between pins 1 & 2 of the LFO schmitt, not 1 & 3. It forms a low pass filter that can help with tick and smooths out the LFO.
Title: Re: Gravity Wave (Verified)
Post by: pierre67 on April 16, 2017, 07:53:18 AM
I just finished mine and it sounds really cool with R9 1K, C9 3,3nF and 2,2µF (MLCC) for C20...Great project !!!
Title: Re: Gravity Wave (Verified)
Post by: bsoncini on May 01, 2017, 05:39:20 AM
This thread inspired me to build one. Built on veroboard from the layout at the tagboard site.

Still haven't boxed it (missing some of the exact pot values) but sounds real good so far. No ticking even with my wires dangling all over the place.
Title: Re: Gravity Wave (Verified)
Post by: wainer said on January 25, 2018, 05:51:59 PM
Good night, I made this pedal but it presents a horrible pop when triggered: even without the led! Does anyone have any suggestions?

thank you
Title: Re: Gravity Wave (Verified)
Post by: selfdestroyer on January 31, 2018, 02:01:31 PM
Good night, I made this pedal but it presents a horrible pop when triggered: even without the led! Does anyone have any suggestions?

thank you

Are you testing this pedal by itself or with other pedals? I would isolate it with just your guitar and amp.

what are you powering it with? If its a OneSpot, is it the only thing plugged in or is there other pedals using the same chain? Try it with its own power source.

Making sure that R1 is 1M and not 1K or any other value.

All I can think of off the top of my head.

Cody
Title: Re: Gravity Wave (Verified)
Post by: wainer said on February 04, 2018, 12:26:28 PM
Good night, I made this pedal but it presents a horrible pop when triggered: even without the led! Does anyone have any suggestions?

thank you



Are you testing this pedal by itself or with other pedals? I would isolate it with just your guitar and amp.

what are you powering it with? If its a OneSpot, is it the only thing plugged in or is there other pedals using the same chain? Try it with its own power source.

Making sure that R1 is 1M and not 1K or any other value.

All I can think of off the top of my head.

Cody

The only way I found was to put a buffer in the pedal output.

Thanks
Title: Re: Gravity Wave (Verified)
Post by: Philtre on February 21, 2018, 03:04:57 PM
Just built this, nice. However, the  Rate is a bit fast, so I plan on replacing C20 (470nF). Some people have used 4.7uF and others 1uF. Which is best? I guess that 4.7uF is the slowest rate?

Edit - I used a 4.7uF polarised. That works nicely. :-)
Title: Re: Gravity Wave (Verified)
Post by: zoof on February 24, 2018, 12:42:04 AM
R9 1K, C9 33nF and 4,7µF for LFO. Works like a charm! Cool pedal!
Title: Re: Gravity Wave (Verified)
Post by: Philtre on February 24, 2018, 01:43:34 AM
R9 1K, C9 33nF and 4,7µF for LFO. Works like a charm! Cool pedal!

The vero layout at the link above is using R9 1k, but 3.3nF for C9.
Title: Re: Gravity Wave (Verified)
Post by: zoof on March 05, 2018, 01:43:32 AM
The vero layout at the link above is using R9 1k, but 3.3nF for C9.
[/quote]

I haven't boxed it yet, so maybe I'll try a 3.3nf and see what it does.
Title: Re: Gravity Wave (Verified)
Post by: amcmann95 on August 09, 2018, 06:11:38 PM
Quick question for everyone-- My voltages all match except for the lm324, which is low-- around .3v. *However*, when I pop it out of the socket, the voltages match perfectly. Problem with the chip Im guessing?
Title: Re: Gravity Wave (Verified)
Post by: m-Kresol on August 10, 2018, 04:01:29 AM
sounds like could be the chip. If you have another one, just try it out.

Could also be that only with the chip inserted you have a connection to something that is then pulling down the voltage. Which pins are out of spec?

Also, what is the problem with your build? No LFO? No Sound?
Title: Re: Gravity Wave (Verified)
Post by: amcmann95 on August 10, 2018, 07:22:05 AM
Thanks for the other suggestions m-kresol. Its pins 10, 12, and 2.

I have no LFO. The only pot that really does anything is the dimension pot. Anything with the lm324 isnt working, including the rate led
Title: Re: Gravity Wave (Verified)
Post by: m-Kresol on August 10, 2018, 10:23:19 AM
ok, so this means you are loosing your reference voltage VB2. since VB2 is only connected to the IC, it would suggest a defective IC.
I would replace it first and hope for the best.
Title: Re: Gravity Wave (Verified)
Post by: B0ttleneck on December 10, 2018, 06:19:40 AM
Hello,
I have a problem with my gravity wave:
I made a homemade PCB and assembled everything.
I made a first test yesterday without putting the footswitch but the result is not good: I have an osciliation output mixed with the sound of the guitar (distorted). pots seems to works.
audio (i play with the pots):
#Invalid YouTube Link#
https://youtu.be/iPWAUoPTICU (https://youtu.be/iPWAUoPTICU)
Photos:https://imgur.com/a/fGBKqGY (https://imgur.com/a/fGBKqGY)

 :o
Where to start checking?
Has someone already had this problem ?

Thanks for your help
Title: Re: Gravity Wave (Verified)
Post by: m-Kresol on December 10, 2018, 10:55:08 AM
Hi bottleneck and welcome to the forum.

Please check the guidelines for getting tech help here: http://www.madbeanpedals.com/forum/index.php?topic=902.0

go through the individual points and you will likely find the problem. So basically, visually check your component values and orientation, check your soldering for solder bridges or cold joints. Check DC voltages on all ICs and transistors (reference voltages by Cody at the beginning of the post). If you can't find the problem yourself, post the voltages and pictures of your pcb and we'll try to help

happy hunting
Title: Re: Gravity Wave (Verified)
Post by: HurricaneHordak on February 13, 2019, 03:36:13 PM
Hello, yous guys!  :D

I was wondering, is this pedal 'verified' to work at all with the components detailed in the b.o.m. in the .pdf file, or am I supposed to do some of the substitutions mentioned? In the process of double/triple checking everything I was wondering, if those subs were crucial in any way.

Atm, mine doesn't make a sound when engaged. Seems like the signal goes to ground at some stage, because it's so damn quiet at the output. Haven't been able to pinpoint it yet though with the probe or staring at it for an hour.  ;) I get lfo noises around the lm324, and I have something of a chorus-ey signal + a tremolo-ey sinus tone at pin12 of the pt2399. Since my theoretical background is almost non-existent I'm often-times confused about what is supposed to be where sounds-wise and feel like I'm probing in a circle.  :-\

Title: Re: Gravity Wave (Verified)
Post by: HurricaneHordak on February 21, 2019, 02:14:57 PM
Alrighty, after finding my superfluous connection between R33 and R15, naturally, I also had the dim pot issue many people had.
I went the C9 = 3,3 nF route + the 4,7 uF for C20, and now I have quite the spiffing pedal.  :)
Title: Re: Gravity Wave (Verified)
Post by: Hoffy84 on June 04, 2019, 07:53:04 PM
Hey Guys,
Sorry to dig up an old thread.
I built a Gravity Wave, and have it on the test rig. Everything is working good, but I too am having the Dimension pot problem. Starts whining between 10-20%. I had done a lot of reading before this build, so I thought I'd be proactive, and went ahead and did the ( C9 change to 33n / R9 change to 10k ) from the start. These are the only mods I did to the original schematic. Before I start dicking around with things, I was wondering if anyone else had this result with just these changes? I thought about changing C20 to 4.7uF, but wouldn't this just make the rate speed slow down a bit? I don't think it would have any bearing on the whining at the dim pot issue.

Thanks, Jeff
Title: Re: Gravity Wave (Verified)
Post by: Hoffy84 on June 05, 2019, 08:18:03 PM
I did some screwing around and got it sounding so much better. Changed the C9 to 3n3, R9 to 1k, and C20 to a 4.7uF ceramic. A few others on the forum did these three mods so I tried it, and it’s a big improvement. No more whining or the DIM pot, but I do get that “motor-boat” effect past 30%. It’s cool though, because there’s noticeable reverb up to 50%, but anything past that is unusable. Changing C20 to 4.7uF makes the rate wayyyy more in range.
This is my first pedal build with a finished enclosure. I’m pretty happy with it. Still have to box it up. It’s not perfect, but OK for a first build. Here’s a couple pics so far. (I have a thing for “The Life Aquatic”. I know it’s a hated movie, but....)