Lovetone clones - Wobulator, Doppelganger

[markusw]

Could it be that the 10uF cap in the feedback of LFO1 is too large?

Seems like you found a bug in the schem  Sorry. To be sure I will check when I'm at home.

I haven't got an audio probe but should be able to work something out.

Basically, you just need a cap (e.g. 1-10µ) and connect it with one side to a guitar cable. Since I'm lazy I connect it with alligator wires.   
Plug the guitar cable into an amp and use the not connected end of the cap to follow the signal path.

Regards,

Markus

[Shed_FX]

Could it be that the 10uF cap in the feedback of LFO1 is too large?

Seems like you found a bug in the schem  Sorry. To be sure I will check when I'm at home.


Regards,

Markus

Thanks for checking, these things are always part of the de-bugging process. I definitiely wouldn't have got half as far without your help.

Thanks!

[markusw]

Hey Sched,

checked again and the LFO's as shown in the schem should be OK. The left channel (low pass) has a slower LFO than the right channel (high pass).
According to the simulations the left LFO goes up to 16 Hz and right LFO goes up to 67 Hz.

Markus

[Shed_FX]

I tried changing the capacitors around last night with no avail. I still can't get the Left LFO to oscilate in sine wave mode.  Thank you for checking it out for me.
But I have found the problem with the sound on the "Out right" I made a mistake on the layout for the Op-amp! I thought I had checked it loads of times Doh!
But at least that gets one problem sorted!

[Shed_FX]

Well, after all of that, it is complete and working! Getting the last bit to work was finding that it required that bit more juice to run certain settings and the battery I've been using for the debug is almost as tired as me! So the schematic is now confirmed, I may play about with the capacitors in the LFO to refine it further, and I think some log pots are required against the linear ones but apart from that it sounds pretty damn cool! I now need to finalise the wiring and have a go at boxing it up.

Next question is.... Does someone else want to give building this thing a try so it can all be double checked and sorted for a project file?
I am going to sort out the changes to my layout to make sure that it is all correct and then I will put it on the forum. What would be great is for someone to give me some pointers as to how to improve it for reducing the tick. The tick on the current board isn't drastic but may well bug people, so it would be good to refine the layout further.

Thank you all, for all of the support especially Markus, it has been a complete pleasure and I am glad to do a service for the forum.

Volunteers please step forward!

[GREEN FUZ]

I`ve been watching this thread with interest. I`d love to give it a go but fear it might be beyond my abilities at the moment. Well done for sticking to it though, and...any chance of some soundclips?

[Shed_FX]

I think it was beyond my abilities too, thats why the debugging took so long! Its not a particularly difficult circuit its just that it was my first layout (bit of a leap) and I had made a few mistakes. I would probably be able to help the next person to get it up and running pretty easily. It depends if people want to re-gig the layout to improve its audio quality, and reduce the tick. The next job is to have another go at limiting the tick as I took a lot of my de-ticking "mods" during the debug.

As for sound clips, Im afraid that i haven't got the stuff to do it. But I would say that the clips on the lovetone site are pretty representative of what it can do. It is a pretty impressive design and has loads of flexibility.

What would be great would be to modify the layout minimising the ticking using all the theories and then get another ginea pig to build one and check it out for real.

[John Lyons]

Sounds like you did it! Good work.
I think if you posted a layout next to a schematic someone should be able to point you in the right direcgtion to get the least amount of ticking.
Thanks for your work on this.

Looking forward to the files.

John

[DWBH]

For the samples I've heard and stuff I've read, the Wobulator is quite similar to the Stereo Panneur from 4ms pedals, isn't that right?

[StephenGiles]

The flanger doesn't sound all that great.

[A.S.P.]

FAT GROUNDS!

Spaghetti traces are good on dishes, but not on PCBs...

[Shed_FX]

I will try and get the corrected layout that I used posted up tonight. Its quite similar to the one that I posted before however I have converted it to dual op-amps. My PCB skils are rather rudimentary!

[markusw]

Hey Tom,


thanks for verifying the schem! 
Glad you got it working!! Congratulations! 

Regarding LFO ticking, maybe it helps to add ridiculously large caps (up to 1000µ) as power supply decoupling caps?
Maybe one for each LFO opamp??

Regards,

Markus

[Shed_FX]

Thanks Markus!

I will try the decoupling caps tonight they helped before in reducing the tick before i removed them during the debug!  The board does look a bit of a mess but Ive always been function over form!

[Shed_FX]

Right here is the layout I used. It's reasonably compact and Ive filled in all of the corrections that are needed for it to work. I did a final trace layout which shows the board mounted rotary switches and stuff but I thought at the moment it would be best showing it just as the main board. The numbers all relate back to the original schem and the big yellow squares are the transformers.
It is an Express PCB file at the moment simply as I found it easy to use and it was the first I found. If there are any better ones out there (I'm sure there are!) please let me know and I can go about transfering it across into a better format.
If anyone want to have the file it's probably easiest to e-mail me and then you can have a go at modifying it.
If no one else wants to have a go, post all of the comments/suggestions and I will develop it (but it will be around other projects).



I think it is pobably best to refine the layout a bit more before putting out a project file (that is almost done apart from the layout!)

[ispeakhopelandic]

hello all,

i would like to volunteer my doppelganger for analysis. also, i may be acquiring some other lovetones, i'm in negotiantions for either a Flange or a Ring Stinger (or both ). if i indeed get them, i'll take some hi res shots, and attempt some analysis too. nice to meet you all.

chris

[markusw]

hello all,

i would like to volunteer my doppelganger for analysis. also, i may be acquiring some other lovetones, i'm in negotiantions for either a Flange or a Ring Stinger (or both ). if i indeed get them, i'll take some hi res shots, and attempt some analysis too. nice to meet you all.

chris

Hey Chris,

welcome to the forum!! 

Thanks for intending to share your lovetones with us! 
The Ring Stinger is already done. http://homepage.ntlworld.com/paul.nelson666/StringRingerv12r.pdf
I would be especially interested in the Flanger    but I'm sure a lot of guys would love to have a look at the Doppelganger!
So if you succeed with your negotiations I would be happy to help with rev-engineering....

Regards,

Markus

[ispeakhopelandic]

thanks! i couldn't find the ring stinger, i knew that i was in the works, thanks for the link. i was really happy reading through the posts before my account was approved to see that folks were figureing out what the ICs were, that was somthing i was quite worried about. i'll get to work on the dopp right away. i'll post pics soon too.

[DWBH]

Yes! We want layouts and pcb's! A full pdf with all that! I would like to help, but my experience isn't that much.

Good luck guys!

[markusw]

i'll get to work on the dopp right away. i'll post pics soon too.

Thanks!