EA Tremolo

[sharp01]

Bicolor leds should be common anode type. Are you shure that yours arn't common cathode?
Try to replace D1 with 4k7 resistor from center to left ( or to right, it depends of 3pdt position). Try both and check again voltages of Q4. For tremolo to work you need collector of Q4 to be not 0v. Now your oscillator isn't working.

[jfrabat]

I think they are.  Now I am not 100% sure, but they are socketed, so I can pull them out and test them to be sure.   Maybe thats the problem...

[jfrabat]

IIRC, I bought this one:

http://www.steren.cr/catalogo/prod.php?f=0&sf=77&c=737&p=704

It does not specify which it is on the site, though.

[sharp01]

There are only 3 components between +9v and Q4 - R12 D1 and 3pdt. D1 can be replaced with atandard led or ~5K resistor. First check your leds and if they are right type then test all stages (r12, d1 and s4 s5 s6 pads) with multimeter. You should find quickly where the problem lies.

[jfrabat]

Will do.  Thanks sharp!

[jfrabat]

Bicolor leds should be common anode type. Are you shure that yours arn't common cathode?
Try to replace D1 with 4k7 resistor from center to left ( or to right, it depends of 3pdt position). Try both and check again voltages of Q4. For tremolo to work you need collector of Q4 to be not 0v. Now your oscillator isn't working.

Well THAT'S your problem right there! (read with thick hillbilly accent!).

If I am reading correctly, common anode share the same positive.  Mine are common cathode (share the same NEGATIVE).

The battery negative is the top side:





I will try to get new ones with common anode.  Maybe that will fix the problem...

[duck_arse]

tsk, tsk! jfra. ALWAYS a current limt resistor when powering leds.

[jfrabat]

tsk, tsk! jfra. ALWAYS a current limt resistor when powering leds.

Even if the battery is 3V?

[duck_arse]

Even.

[jfrabat]

Good to know...

[EBK]

The current limiting resistor was inside the battery. 

[jfrabat]

The current limiting resistor was inside the battery. 

Was it?

Oh, yeah, yeah, it was... 

[sharp01]

tsk, tsk! jfra. ALWAYS a current limt resistor when powering leds.

Always, but not in this case. It was wrong led anyway, so who cares?

Ps: yes, current limiting is a good thing. Even with 3V.

[jfrabat]

Just wanted to report in.  The electronics of this project are done and the Tremolo is working correctly.  I ended up using regular LED's, and I am now working on the enclosure.  Thanks for the help, guys!

[robthequiet]

Excellent, please give updates.

[jfrabat]

Here's how it is looking as of today.  Still need the graphics, but I do not yet know what I will name it.  Once I decide that, I will work on the graphics (EA Tremolo is just boring!).  Function wise, the pedal works as advertized.  Only issue is the speed pot is backwards, but that is simple to fix.

[Kipper4]

Great job.

[duck_arse]

jfra - it looks vrr nice. vrr green. about the speed pot - is it backwards-but-smooth-change, or backwards-and-all-bunched? if it's the first, leave it, or get a reverse log pot. if it's the second, it's wired backwards.

[jfrabat]

I do think I wired it wrong but I do have reverse log ppts at home if I need them.  I will double check tonight

[Ben Lyman]

Looks great! I love the color.
Leave the speed pot backwards and label it "Brake" and call the pedal the "Traffic Light Tremolo"