*UPDATED*
I discovered I had skipped Q13, just needed to put that in and the effect works! doh!
Questions about the Max Speed, and treadle friction below, thanks!
Hello,
The Lamp does not light up.
bypass is clean, and when I engage the pedal the LED lights up, guitar signal passes cleanly with some change in tone, knobs and switches have mildly noticeable affect.
Majority of my voltages are spot on the PDF, with some minor discrepancies.
I'm getting about 14v on the positive side of the Lamp. But with it in place there is 14v on both pins - does that indicate a bad lamp?
I measure about 60ohms on my DMM between the two lamp pins.
The lamp came with the PCB, I don't think I blew it, but maybe I did, is that common?
It's a two-pin 18v Lamp,
the socket for the lamp has 14-15v on the positive side, I put a blue LED in there and it pulses, but it's pretty dim.
Is there a voltage or amperage I can measure on that socket to see if the 18v Lamp should be working?
thanks for helping!
It sounds like you need to adjust the two trimmers... Start at the mid-point on both trimmers. One trimmer sets overall brightness of the lamp and the other trimmer sets the offset, which is basically how dim the bulb gets.
thanks danfrank.
For the record, I was EXTREMELY careful while building this to avoid a quagmire of debugging. I actually measured every component, cross-checked the schematic, BOM, and diagram, and marked them off one by one. Yet, somehow I completely skipped over Q13 LOL!
Once I discovered that the lamp works and the effect works, very cool sounds.
But I have two more questions, hopefully someone will read this:
1- how can speed up the 'tremelo', even at it's fastest it still feels kinda mellow
2- I got the Wah enclosure from Alibaba, it's made from Aluminum (not like a real Crybaby enclosure) but it's fine.
The treadle doesn't have enough friction to stay in place mid-way, it drops down on its own.
Any tips on what to do to make it more frictiony?
Regarding changing the speed range I did these mods that another forumite posted years ago:
Changed speed pot range so I can get faster speeds and slower too (Change R52 to 470R and jumper R54).
That makes it pretty fast in extreme treadle position. I might experiment with values a bit more after playing it awhile like this.
You can check out my build report here:
https://www.madbeanpedals.com/forum/index.php?topic=33713.msg324033#msg324033 (https://www.madbeanpedals.com/forum/index.php?topic=33713.msg324033#msg324033)
holy crap Cooder, that is beautiful!
I'll look at your suggestions on the speed mods thanks
But can you offer any help with the Enclosure? It looks like you started with the same aluminum enclosure kit I have, it seems like I missed something on assembly. My treadle is loosely flopping around (not that loose but not correct).
What are the three screws at the back attached to? [see pic]
Actually, I have a bunch of left over screws and bits from the enclosure kit. There's a block with a long screw (allen wrench, like a truss rod) that I figured went on the axel as a tensioner but it doesn's seem to do anything...
I solved the floppy treadle problem with a nylon washer, just squeezed it in there so the hinge is tighter.
I socketed R52, R54 and the mods Cooder suggested definitely sped up the max speed, although it shifts maybe too abruptly now. I can see how a higher K pot could help because the sweetspot is narrow toward the heel position.
I might try some other values in R52, R54 - they went from 27k to 0.47 and 0, a big difference.
Maybe somewhere around 5k7 or something is what I'm after. I'll mess with it again another day, but for now I'm stoked!
Thanks guys
What I did to make the treadle more stiff is I put some rubber grommets in between the inside of treadle and hinges on bottom enclosure that gave it a nice wiggle free action that is stiff enough.
To try that you will need to press the axle out again and find some suitable rubber grommets or bit of hose that sits snuggly on axle.
Tightening those screws won't make a difference I would think.