Baja Trembulator schematic, board layout and circuit board

bajaman · Post by **bajaman** » 19 Sep 2008, 02:49

Hello Roa
Just go to the three links (blue letters) below my signature on the first post - all the info is there

Baja Trembulator schematic
Baja Trembulator pcb tracks
Baja Trembulator board layout

cheers
bajaman

Orkspalter · Post by **Orkspalter** » 04 Nov 2008, 16:08

Hey Baja,

will you do a stereo version (mod) for theTrembulator as i saw you´re working on an nice stereo amp?!:-)

bajaman · Post by **bajaman** » 04 Nov 2008, 18:09

Hey Baja,

will you do a stereo version (mod) for theTrembulator as i saw you´re working on an nice stereo amp?!:-)

No plans as yet

bajaman

Barcode · Post by **Barcode** » 01 Feb 2009, 04:56

So, built it, great project! Oly one little odd thing happening: whenever i first power up the pedal, if the rate knob is not set to near minimum, it won't trem (and the LED doesn't flash). But, if i lower the speed down to about 2, then the LFO kicks in and everything starts working? If i plug it in while the rate knob is already down to around 2 or lower, it comes on right away. any thoughts? I'm thinking i may have damaged my tl061 i used for the lfo when i salvaged it from another build. thoughts?

bajaman · Post by **bajaman** » 01 Feb 2009, 08:24

Sorry - never had that problem - built about 4 of them with no problems whatsoever.
bajaman

Barcode · Post by **Barcode** » 01 Feb 2009, 16:19

bajaman wrote:Sorry - never had that problem - built about 4 of them with no problems whatsoever.
bajaman

i'm pretty sure it has to be the opamps. i used a tl072 for the dual, but all i had in singles was a 741 and a salvaged tl061. i will try to get the right parts and report back if that solves the problem or not.

sonicvi · Post by **sonicvi** » 03 Feb 2009, 23:49

Would a VTL5C2 work as well as the VTL5C1 in the pedal? I happen to have an extra one. Thanks!

Barcode · Post by **Barcode** » 04 Feb 2009, 01:32

sonicvi wrote:Would a VTL5C2 work as well as the VTL5C1 in the pedal? I happen to have an extra one. Thanks!

as long as it is a single LED and a single LDR (four legs) it should work. ymmv.

aloupos · Post by **aloupos** » 28 Feb 2009, 17:51

Baja, thanks for this great circuit. I've been using it for a year now.

I'd like to add a switch to square off the wave, so I can get a more choppy/less smooth effect. Is there any way to do that?

TIA

bajaman · Post by **bajaman** » 28 Feb 2009, 20:03

Hi Aloupos
You could try adding a small capacitor in parallel across one of the 220n capacitors in the oscillator section - try 10n - 47n for example - it may make it a bit more choppy.
cheers
bajaman

aloupos · Post by **aloupos** » 01 Mar 2009, 23:50

I'll give that a try, thanks baja! I'm cringing when I'm asking you this, because I know you went through great lengths to make this a really smooth trem, but, any way to completely square it off -- ie very choppy?

bolbo_1 · Post by **bolbo_1** » 18 May 2009, 06:25

Hello all, my 1st post on this site.
Are there any decent sound clips of this pedal in action any where on the web which demonstrates amount of depth and speed range achievable ?
Thanks Bolbo_1

sonicvi · Post by **sonicvi** » 27 May 2009, 05:51

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

bolbo_1 · Post by **bolbo_1** » 27 May 2009, 13:19

Sonicvi, many thanks for the clip, sounds really good.

Question, Is anybody on this site able to make up a PCB of this at a reasonable price. I'm new to DIY effects - I've only made a couple of simple effects so far (all on perfboard) and so far my skills are very limited - I would like to fit this in the smallest enclosure I can.
I live in Perth, Western Australia.
Thanks

jrc4558 · Post by **jrc4558** » 28 May 2009, 20:01

Hi everybody!

I would like to ask a question about the schematic. Has it been verified? I learned about an input capacitor omission in the drawing on the first page. Is there anything else? I made my own layout (somewhat smaller) based off of the schem on the first page and want to make sure that it's correct before I etch.
Anyone wants to take a look? I have no part numbers on it though...
Thanks! And thanks to Bajaman for all his work!

sonicvi · Post by **sonicvi** » 29 May 2009, 14:04

Yes, it works. See my last post two above yours to hear it.

Camphausen · Post by **Camphausen** » 10 Jun 2009, 05:23

What is that 10k TrimPot for? Is it actually the wave shaping control?

regards

alcide · Post by **alcide** » 11 Jul 2009, 12:13

Hello everybody!
This is my first post on this site, so let me say at first how pleased i am to get involved in this discussion (even if my poor English should have inspired me an eternal mutism: excuse me, by advance, please...)
I've just finished building your trembulator, dear Bajaman, using a Kingbright KB817 (reversed polarity for the led) instead of the vactrol. Everything works fine (gorgeous waveform) except for one thing: the pedal boosts the signal so much that it distorts (slight overdrive), and this distortion is louder when i increase the "depth". The only way to avoid this problem a bit is reducing the volume of the guitar output. Is there a relation with the "off resistance" of my optocoupler (which i couldn't find in the datasheet)? Any idea?
Many many thanks, may you find or not a solution to my poor ignorant newbie problems !

bajaman · Post by **bajaman** » 11 Jul 2009, 21:35

try increasing (or removing) the value of the 10k resistor connected between the inverting input and the junction of the twoo 100k resistors in the biasing network of the first TL061 op amp.
Try values up to 47k - this will reduce the gain of the tremelo effect and prevent your guitar from overloading it.
cheers
bajaman

alcide · Post by **alcide** » 12 Jul 2009, 06:52

Dear Bajaman,
I think you'll have also to debug my brain, and answer this other crucial question: why am I so dumb? The output of the KB817 isn't a simple photocell, but a phototransistor...

A friend of mine gave me a proper vtcl, I soldered it this morning and...C'EST MAGNIFIQUE !!!
Truly, the best sounding tremolo I've ever heard.
Many many thanks again.
Alcide.

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