Hi guys,
It's a long time since my last post. The last months I was in a rabbit hole called BBD flangers... So what I did was adapt the ultraflanger to use a v3207 BBD. I also made some other changes trying to improve this pedal. The schematic now looks like this:
(https://i.imgur.com/eUZOrnqh.png)
I added the decoupling after de BBD and adjusted the bias of the second OPAMP, now it won't distort as easy.
I added a trimmer to set the gain of this stage, since now it was giving me twice as much swing.
I tried to measure the clock frequency with the cheap chinese scope (from the 20 bucks kit) and it seemed to oscillate between 35khz and 220khz. So the lower limit is ok, the top limit I guess is just too close to the scope's limit of 500khz, where the input capacitance gets most of it (probably)
The final result:
(https://i.imgur.com/Yg9FCFEl.jpg)
(https://i.imgur.com/CzebdM2l.jpg)
The ground plane is totally worth it. I had to add some resistors at the lower side to get the shortest path to the inputs as possible. That solved the weird switching noises from my first board. Now I can say that it is really quieter.
(https://i.imgur.com/nkZQHGfl.jpg)
(https://i.imgur.com/wQWYkhEl.jpg)
(https://i.imgur.com/V1dp7xtl.jpg)
Now some curious stuff I observed...
1- With the depth/width pot fully at CCW there is still some small signal of the LFO coming through when the speed is set at minimum. It is just noticeable when combined with a distortion pedal. Is it because of the 47uF capacitor to ground? Should I put a 1000uF in there, or can I ground one of the sides of the pot?
2- Even with lot's of caps I couldn't get rid of the ripple at the LFO 3.9v. When using a zener I had to put a 1k resistor in place of the 10k normally found in the old schematic. That can't be right. Is this LFO really this hungry at lower speeds? Note that the CD4046 and de 4049 have their own node.
3- I should adjust the mix (actually the gain of the second opamp) so that both signals are mixed 50/50 right? I'll have to reduce the 100k after the BBD too, otherwise the gain of the BBD + unity gain stage still is more than the dry signal.
It's sounding good as it is, but really intense, I only can get the jet like sound when using distortion. Even with the Regeneration at full CCW it's like a parked jet...on the other hand, it is not oscillating unless the gain of the second opamp is higher than 1.5! I guess I'll have to adjust the trimpot at the first opamp too...
Daaaammnn That's nice and small. That looks very neat.
Wow- these tiny builds of yours leave me in a stupor. The circuit building, pcb planning/etching, the micro-soldering, the pro' shoe-horning, the waste-less wiring, all topped off with super cool and detailed artwork.. Just-Wow, dude- thanks for sharing, I really enjoy looking at these!
I'm going to pretend I never saw this and quietly back away...
Quote from: dawson on February 07, 2020, 08:27:05 PM
Wow- these tiny builds of yours leave me in a stupor. The circuit building, pcb planning/etching, the micro-soldering, the pro' shoe-horning, the waste-less wiring, all topped off with super cool and detailed artwork.. Just-Wow, dude- thanks for sharing, I really enjoy looking at these!
What he said....amazing work
If this was a competition this would be my cue to give it up. Unreal work sir
Sent from my LM-X410PM using Tapatalk
i have favorite builder when addicted to pain build small headphone amp, the miniaturization guru, the one and only sijosae (http://has.pe.kr/ftp/sijosae/Gallery/)
now, in pedal build, i found LB Master again. You Krazee. I like it.
my commision build in LB, Freddy fuzz and Eternity give me enough stress and hold my courage to build LB again. Hahaha
You Rock!
Quote from: 287m on February 08, 2020, 07:10:17 AM
i have favorite builder when addicted to pain build small headphone amp, the miniaturization guru, the one and only sijosae (http://has.pe.kr/ftp/sijosae/Gallery/)
You might need to pick a new favorite micro amp builder, because thomasha does that too... https://www.madbeanpedals.com/forum/index.php?topic=29072.0
Everything about this pedal is fantastic- the layout, the build, the graphics. All of it
If you adjust the gain with R9/10 you'll adjust the Q of the filter, it can only reach a Q of ~3 Before it oscillates, it's not a good place to adjust gain at all, you'd be better off either adjusting gain via R7 or R13.
Or you could change R8 to 100k, move R32 to the other side of it and reduce it to 91k, the node will look ~47k to the filter, you'll have your reference voltage and the signal will have been divided.
Your sweep is probably poor due to the new 10k/10k divider for the LFO, at 3.9V it was swinging further to ground.
Thank you guys for the kind words!
Sijosae still is a motivation to build smaller tube amps for me too!
Thanks Scruffie for the tips!
Quoteyou'd be better off either adjusting gain via R7 or R13
I tried it. To get te same swing the resistor should be 11k instead of 100k. It is probably working with the 4.7k resistors as a divider, that's why the low value. At this value the bias voltage is also better and the decoupling cap is not necessary. So that is a different way to correcting the circuit.
QuoteYour sweep is probably poor due to the new 10k/10k divider for the LFO, at 3.9V it was swinging further to ground.
I changed the resistor to ground, to get closer to the 3.9v. The thing is that it has a ripple from 3.7 to 4.0, that looks huge, even with the 47uF capacitor to ground.
TL072 is a a lousy LFO op amp, try an LM1458 or LM358 and see if that helps the ripple.
Such an impressive build. Hope you can sort the oscillation
Friggin' unreal.... 8)
Awesome! Thomas, can you take a pic of all your tiny arsenal plugged into one of your kick ass mini tube amps? It would be such a cool pic.
Quote from: selfdestroyer on February 12, 2020, 03:39:47 AM
Awesome! Thomas, can you take a pic of all your tiny arsenal plugged into one of your kick ass mini tube amps? It would be such a cool pic.
and put a Lego figure next to it as reference!
I never stop to be amazed by your work. no idea how the pcb fits with jacks and stomp... :o
Quote from: m-Kresol on February 12, 2020, 06:26:37 PM
I never stop to be amazed by your work. no idea how the pcb fits with jacks and stomp... :o
This! It must be all an optical illusion like they do in movies where they make things look bigger or smaller than they are... optical sorcery... it must be...
Insanely well done!
What is this, a pedal for ants? The pedal has to be at least three times bigger than this!
Finally took some time to make a video of it
I need to go lay down...
wow... sounds great!
Hi guys!
Because this build ended up receiving lots of votes, I decided to make a small PDF with some extra tips, in case someone wants to build one too.
https://www.dropbox.com/s/xrmpvlmfmwrq113/Ultraflanger_thomasha.pdf?dl=0 (https://www.dropbox.com/s/xrmpvlmfmwrq113/Ultraflanger_thomasha.pdf?dl=0)
In case you want to make your own layout, or make some changes, I also added the eagle files I used.
If it could somehow be smaller.....
Sent from my iPad using Tapatalk
I'm even more impressed, now, at the supreme cramming of things you pull off!
I have built it, the flanger is audible, but it doesn't oscillate automatically, there is no "swoooooossshhh" sound .. to get the "swoooooossshhh" sound like your flanger. I had to rotate the RATE pot to the right and the left repeatedly. where is the problem? i don't know because i am a beginner. sorry for that and also for my english. Thank you. greetings from Indonesia :-[ ;)
Quote from: Coldjoiner on April 12, 2021, 07:01:53 AM
I have built it, the flanger is audible, but it doesn't oscillate automatically, there is no "swoooooossshhh" sound .. to get the "swoooooossshhh" sound like your flanger. I had to rotate the RATE pot to the right and the left repeatedly. where is the problem? i don't know because i am a beginner. sorry for that and also for my english. Thank you. greetings from Indonesia :-[ ;)
sounds like your oscillator is not oscillating? please follow the guidelines in the tech-help section so we can help you properly. Measure voltages of all ICs and post some pictures please. Did you test it outside the enclosure?
choosing a "nano"-project for a start might not be the best way to go. I would encourage you to try something easier and bigger to begin with, if you cannot get this one going.
Hi,
that sounds like the LFO. Do you have any oscillation at the speed knob?
Hi again,
I just finished a second one, and found some mistakes in the eagle file (I already corrected the PDF).
The mistake was, that I had both a 10k 10k voltage divider and a 10k 3.9v Zener divider in the schematic and in the layout.
My suggestion is: use the zener and adjust the 10k resistor if necessary. The 10k+10k voltage divider will not be enough to keep the voltage at 3.9v.
It will depend on the OpAmp used for the LFO.
The TL062 is the best choice here (the TL022 is not that common I guess), the zener and the 10k resistor will work, worst case you will have to decrease the resistor to achieve the 3.9v.
The TL072 will also work,but the resistor has to be 1k instead of 10k, otherwise the zener wont be able to draw enough current to keep the voltage at 3.9v and it will drop, turning the LFO off.
In this build I tried to use a RC4558 as the LFO OpAmp (The only damn thing I had left) and it was really bad. It stopped alone at frequencies below 1Hz, and I definetely want my jet sound to be way slower. It also required the 1k+3.9v zener to keep the voltage at 3.9v.
I tried reading a little bit about how I could improve the LFO for such a bad chip (I had designed a LFO for a 12AU7 before), but I only had a couple of days to finish this one (its a gift to a friend), so that I did not had the time to read/simulate stuff. Actually, the simulation was always more stable (it always oscillated, even at 0.05Hz) than the LFO in my build. As a last resort I just removed a TL072 from another build (good times, I still used sockets) and that improved the LFO. So with the values in the schematic the RC4558 as a LFO is a bad choice.
To conclude, I would definitely check the LFO chip and the voltage at the pin 1 of the DEPTH/WIDTH potentiometer. It has to be 3.9v no matter what.
If someone has some nice reading material about LFOs and how to increase the stability (in this case the oscillation, lack of stability?) of the LFO so that I could also use the 4558 at low frequencies (below 1Hz), I will be very happy.
wow.. very cool.. thanks a lot thomas.. this is a great pedal.. this is awesome..
by the way, i use opamp TL062 for lfo.. but it seems the sweep feels not wide enough.. i try to replace it with TL072 but the reaction is still the same ..
maybe I will check the voltage on each leg of the IC another time ..
hmmm .. any tips and ways to make the sweep wide ..? thanks a lot thomas..
Hi,
check if the the voltage are correct. As said, the bias should be around 3.9v. The tl062 worked better in my builds, with less voltage variations in the bias.
You can also adjust the circuit of the LFO to increase the sweep, but watch out, or it might get unstable and just stop the LFO, so make some tests with different values with small changes.
a thousand thanks for the advice, thomas. I adjusted the resistor as per your suggestion. I still use a 10K+10K voltage divider. I just adjusted the 10K resistor that supplies the 3V9 zener voltage. I used 1K8 resistors. with a 1K8 resistor, it will produce a bias of around 3.92V. with TL062, it oscillates very very well. the strokes are a bit wider and I'm fine with that. As a beginner this is a pedal that is quite difficult to build. but this is a great first collection of diy pedals for me. once again thanks a lot thomas. sorry for my english.