Baja Trembulator schematic, board layout and circuit board

DimebuGG · Post by **DimebuGG** » 16 Jul 2009, 12:00

Hi Bajaman,

Any thoughts using a quad opamp on this?..Actually, I've design a layout using a quad opamp.

Louishr · Post by **Louishr** » 24 Jul 2009, 20:54

I have a bit of a weird problem, I built this pedal using a perfboard layout I did myself, so I probably messed up somewhere I'm just having a hard time locating the exact problem. Here's what happens, when I first power up the pedal everything works but only for 2-3 seconds, the light is flashing and it tremolo's fine, but over those first few seconds the led flashes less and less until it is just constantly lit up, at this point the tremolo stops. I'm assuming that the led in the LDR is doing the exact same thing, which would explain why it isn't working properly. Somewhere on the board power is building up and not draining properly. I made the board in two pieces because I combined it with a zvex style sequencer, so I can switch between normal tremolo controls and the sequencer. here's an image of the layout of just the two boards pertaining to this pedal. The board on the left is the schematic from the input up to the LDR, the board on the right is all the controls and that is where the problem is because the pedal works just fine with the sequencer controls (not shown)

jrc4558 · Post by **jrc4558** » 30 Jul 2009, 05:21

I have finally got to testing m own layot for this smooth sounding tremolo. It worked, minus one minor error (Ratepotentiometer was connecting to the ground instead of Vref). Now I have a couple of questions about this effect.
While I love the shape of the LFO, I can't help but to want more depth and higher speeds. I think reducing the 10k that connects to the 50k Rate potentiometer should do the trick. The depth issue, however, seems to be entirely dependent of the LDR, as there is no resistor before it to alter the value of the voltage divider and such. What I really am looking for is the speed and depth of Pink Floyd's Money, which I do get with EA Tremolo. now, I've always wanted a tremolo with no volume control to it, and Trembulator seems a wonderful candidate if I could tweak it a bit. What would you recommend to increase the depth of this effect? I am thinking a j-fet with gate to where the optoisolator's LED+ side connects right now. Any other suggestions?
Thank you Baja for the wonderful project!

jrc4558 · Post by **jrc4558** » 30 Jul 2009, 05:23

I think I should refine what I mean by Depth here. I don't mean the about of LFO signal modulating the resistance of the LDR. I mean a greater amplitude, or swing in maximum and minimum volume when the Depth is at maximum.

bajaman · Post by **bajaman** » 30 Jul 2009, 07:54

For a greater depth try reducing the 50k depth control to 10k and increase the output coupling capacitor from 1uf to 4.7uf.
That should do the trick.

cheers
bajaman

jrc4558 · Post by **jrc4558** » 30 Jul 2009, 13:44

Awesome! I checked with the voltage divider and it makes sense. Thanks Bajaman! I will publish the layout as soon as I verify it with these values.

ron123 · Post by **ron123** » 14 Aug 2009, 02:13

Louishr wrote:I have a bit of a weird problem, I built this pedal using a perfboard layout I did myself, so I probably messed up somewhere I'm just having a hard time locating the exact problem. Here's what happens, when I first power up the pedal everything works but only for 2-3 seconds, the light is flashing and it tremolo's fine, but over those first few seconds the led flashes less and less until it is just constantly lit up, at this point the tremolo stops. I'm assuming that the led in the LDR is doing the exact same thing, which would explain why it isn't working properly. Somewhere on the board power is building up and not draining properly. I made the board in two pieces because I combined it with a zvex style sequencer, so I can switch between normal tremolo controls and the sequencer. here's an image of the layout of just the two boards pertaining to this pedal. The board on the left is the schematic from the input up to the LDR, the board on the right is all the controls and that is where the problem is because the pedal works just fine with the sequencer controls (not shown)

did you ever figure this ot mines doing the same

Hauge · Post by **Hauge** » 16 Aug 2009, 19:52

ron123 wrote:
Louishr wrote:I have a bit of a weird problem, I built this pedal using a perfboard layout I did myself, so I probably messed up somewhere I'm just having a hard time locating the exact problem. Here's what happens, when I first power up the pedal everything works but only for 2-3 seconds, the light is flashing and it tremolo's fine, but over those first few seconds the led flashes less and less until it is just constantly lit up, at this point the tremolo stops. I'm assuming that the led in the LDR is doing the exact same thing, which would explain why it isn't working properly. Somewhere on the board power is building up and not draining properly. I made the board in two pieces because I combined it with a zvex style sequencer, so I can switch between normal tremolo controls and the sequencer. here's an image of the layout of just the two boards pertaining to this pedal. The board on the left is the schematic from the input up to the LDR, the board on the right is all the controls and that is where the problem is because the pedal works just fine with the sequencer controls (not shown)

did you ever figure this ot mines doing the same

Hi.
Try to break the track that goes straight down from the left side of R9 on the layout.
I build the circuit today using the scematic and Louishr's layout (on one board though) and after a couple of rookie mistakes I've got it right. Sounds great all though my Depth knob isn't working proberly. When I turn it clockwise the signal is boosted a bit and the tremolo effect is less audible. I've also reversed the Rate knob somehow as the speed decreases when turned cv.
Aside from my mess ups it's a great build. I use it for bass and it's really smooth.

Martin

Waimana · Post by **Waimana** » 02 Sep 2009, 10:24

kia ora baja
just building this up now, can i use an LM358 in place of the LF442?
cheers

bajaman · Post by **bajaman** » 02 Sep 2009, 10:44

I suppose you could use the LM358, although I have not tried it.
cheers
bajaman

devastator · Post by **devastator** » 11 Sep 2009, 22:19

i think I'm gonna make that tremolo pedal, but just one question, I can have a chopped sound with it ? an extrem tremolo ? or that stay soft even with the speed at max ?

Waimana · Post by **Waimana** » 13 Sep 2009, 00:39

bajaman wrote:I suppose you could use the LM358, although I have not tried it.
cheers
bajaman

thanks for that bajaman, fnished it today with LM358 and homebuilt vactrol with red LED, garden pipe and LDR, sounds fantastic!!! thanks for the build notes...replaced 10k with 4k7 for faster rate speed...very happy with this, highly recommended...has more depth than the EA in my opinion...thanks once again

stanimal08 · Post by **stanimal08** » 15 Sep 2009, 14:49

BAJAMAN HELP!! I've built the Trembulator but cannot seem to get it to work properly. All the parts are correct, even shelled out the cash for the VTL5C1 but when i first plugged it in the LED came on but was solid and not pulsating... when i picked up the board it suddenly began to trem, i realized i had my fingers in specific spots on the board (ground and speed pot solder points) and when i attached a wire to jump from those two points it began to work... BUT it only pulses at about half the rate... here's where it gets weird (and possibly not for you but for me because i'm still new to the game) when i place my finger on a specific spot on the solder side of the board (again, totally by accident i discovered this) it pulses like crazy at the speed i'd ultimately want.... the spot seems to be around the 4k7, 18k, 220n, and 2m2 just below the LF351 chip.... i have no idea what i may have done wrong here, but do you have a clue....?

by the way, this is the third Baja build i am doing, the first to not work right away, as silly as this is consider yourself admired, all my baja builds are my favorite pedals by far (and i have some pretty $$$ boutique stuff as well)....

is it wrong that i imagine Bajaman on a cliff with a cape and soldering iron ready to combat evil and newbie dork mistakes.....?

Waimana · Post by **Waimana** » 15 Sep 2009, 20:31

sonicvi wrote:Here's a clip. I put the Trembulator and RG Keen's Vibratone brownface vibrato in one box with a three way rotary switch (trem/vib/vib into trem). This clip has all three, but the Trebulator starts at about 1:45. One resistor controls the maximum speed, so you can set it to whatever you want really. I don't think this clip has the fastest or slowest that my build is capable of. Its a fantastic tremolo. If you want the Blackface tremolo sound you won't be disappointed. Kudos to Bajaman.
http://homepage.mac.com/sonicvi/bandt.mp3

Hi Sonicv, i like this idea and have recently built up a board of the Vibratone plus one for the Trembulator, can you describe how you the rotary switch works and how you have it wired? Cheers Andrew

devastator · Post by **devastator** » 16 Sep 2009, 17:16

it's possible to add a third control into the circuit (for the shape maybe) ? Otherwise I'll add a volume stage at the end (like the tremulus lune)

I'm gonna order the PCB to make that tremolo pedal which seems to sound really cool.

mictester · Post by **mictester** » 20 Sep 2009, 12:22

bajaman wrote:Hi

bajaman

Baja Trembulator schematic
Baja Trembulator pcb tracks
Baja Trembulator board layout

Hi

I found that your tremolo is fabulous - thanks for contributing it. However, I found that it could be affected by the input impedance of the following device (whether another stompbox or an amplifier), so I added another op-amp with unity gain just to give a low impedance output. You could use an additional IC or make the first stage a dual (TL 062). A suggested schematic is attached:

: BajaTrembulatorschematicModded.png (10.25 KiB) Viewed 2548 times

You'll find that this makes the device more useable at little extra cost. I'll forward my modified PCB design if anyone wants it.

sinner · Post by **sinner** » 20 Sep 2009, 12:24

mictester wrote:I'll forward my modified PCB design if anyone wants it.

Would you like to post it here?

devastator · Post by **devastator** » 20 Sep 2009, 12:44

the PCB in frst post is correct ? I'll make an order to build that tremolo.

mictester · Post by **mictester** » 20 Sep 2009, 14:49

sinner wrote:
mictester wrote:I'll forward my modified PCB design if anyone wants it.
Would you like to post it here?

Certainly will. It's on another machine, and I'm enjoying the cricket this afternoon. I'll post either later today or tomorrow.

sinner · Post by **sinner** » 20 Sep 2009, 15:39

mictester wrote:
sinner wrote:
mictester wrote:I'll forward my modified PCB design if anyone wants it.
Would you like to post it here?
Certainly will. It's on another machine, and I'm enjoying the cricket this afternoon. I'll post either later today or tomorrow.

Lovely, good luck then and thank you

Baja Trembulator schematic, board layout and circuit board [documentation]