freestompboxes.org

Hi
Check out my posts at this link
https://www.freestompboxes.org/viewtopic ... stompboxes
cheers
bajaman

Baja Trembulator schematic
Baja Trembulator pcb tracks
Baja Trembulator board layout

Looks cool. Could I use a Clairex CLM-6000 for the opto part? I've got a handful I bought yeeeeeaaaarrrss ago back when they could still be easily had from Mouser

Yes - they should work fine, although i have never used them.
I used a homemade optocoupler - a cheap philips LDR and a red 3mm LEDmounted inside a piece of black plastic tubing - the kind that is used for risers in a garden watering system
I cut the riser into 0.6 inch (15mm) lengths and insert the led in one end and the ldr in the other, then I carefully seal each end with black goop or black silicone rubber compound - wahatever as long as it is opaque.
It works fine and is MUCH cheaper than a vactrol unit
cheers
bajaman

gah, I'm gonna have to build this as well now! My list is growing

Wow, great stuff Baja, thanks, will put those parts on my next order.
Was debuggin my Hotcake few days ago didn't get round to audio probing since.

thanks!

I will put this on my list too. Thanks bajaman

You are all welcome to build it - it is my gift to the community - I nearly sold the third one yesterday - but the guy's wife is expecting their first child in 2 weeks time, and he was practising restraint
Seriously though - build it - you WILL like it
bajaman

Hi folks
I made two mistakes
There is a missing 47n coupling capacitor at the input of the TL061 on the schematic, and the 10k resistor connected to the speed or rate control is shown as 1k in the parts layout picture.
I have amended and reposted on photobucket please change or re-download the corrected versions.
Sorry for the errors
bajaman

Very Cool bajaman!
Where's Jay??
Here's ANOTHER Original circuit!!
Nice work indeed.
Thank You.

Hi Markm
Like all ORIGINAL circuits it is based on something old - in this case the Demeter tremulator and a NS design brief for an easily tuned sine wave oscillator.
All i did was refine the oscillator section which i thought was lacking.
This of course is one of the major benefits of this forum, as schematics are posted, we can tweak them and sometimes obtain a completely new circuit that exceeds our expectations.

Where's Jay??

bajaman

Hello Guys and Gals
SORRY - I made a couple of errors with the Baja Trembulator PCB tracks.
These have been corrected and the links now point to a fully working and verified track layout. I have just built two pedals, and wondered why they did not work correctly, until I discovered my mistakes. Again my apologies to anyone who downloaded the previously incorrect PCB layout.
bajaman

Hey thanks for updating so fast!

What specs of LDR do I look for if I can't find the vactrol VTL5C1? It's more expensive that the rest of the components together:
http://www.banzaieffects.com/Vactec-VTL ... 17339.html

zj

Hi Modman
Forget the Vactrol device - it is way too expensive .
Any ldr will work fine - There is a small Philips ldr about 5mm diameter - the same as in those old Morley wah pedals, that i use - all the local electronics stores have them for around $2.50 each.
I use a standard cheap red 5mm led, and mount it and the ldr facing each other in a black pvc plastic garden watering system riser tube. I have to drill the inside of the tube out to 5mm and grind off the lip on the bottom of the led - not a major problem Then I seal each end with black silicon rubber or black superglue etc., to stop any light getting in. That is it - and it works very well in this circuit.
Hope you like it - everyone who has seen and heard mine wants to buy it
bajaman

PS: any opamps work fine, BUT the LF422 and the TL061 are low current devices, and therefore extend the battery life considerably.
I have built one with TL072, and two TL071 devices - it works fine, but consumes more current - that is all

Hi again
This is the one I use - very high off resistance 10M ohms

http://www.jaycar.co.nz/productResults.asp?FORM=KEYWORD

then - enter the code RD3480

Cheers
bajaman

I should really have checked futurlec's LDR's at $0.25, three types but not specified. I walked into an electronics shop today and picked up two LDRs and paid 3.10EUR abd 4.10EUR for a small square LDR and bigger round black one.

But the off value of the big one seems to match yours. At this price, I could have gotten the vactrol

Now you know why I love futurlec. Did get the last three LF351 they had at 2.30 EUR! $0.85 at Futurlec.

Anyways, if my printers loves me I might still be doing the transfers.
Do have to order that second IC then, or are there alternatives to the LF442?

zj

Hi modman
ANY dual op amp will work - the LF422 is just a low current drain device - i have used TL072 successfully.
bajaman

Ok that's great, I have those in stock.

Etched the board and it came out just great:



so far, so good, it's been some that I last etched a board...
let's drill.

baja, would you second an idea of a separate projects folder? It would contain all elements needed to build (verified schemo's an layouts). or would you as lief keep it a bit out of side like here. it's all up to you. just lemme know what you think!

Hi Modman
That is the wrong board
It has two track errors on it, but is simple to fix.
Download the new verified PCB track board from the photobucket links,
or modify as per this drawing. Red = break tracks. Black = join tracks.



Cheers
bajaman

A separate projects folder would be a good idea
Cheers
bajaman

Great work Steve! I can verify fellas that this is one very awesome sounding trem. Very smooth.