Ea tremolo light rate

[jimbob]

How do you get this light mod that pulsates to the rate to turn off with the rest of the  pedal when switched off..And- how can you make the rale a little slower?

thanks

[Travis]

The improved EA trem at ROG has the led mod.  To slow the pulses further than what the rate pot allows, increase the size of the 1uF caps on the right hand side of the schematic.  Doubling the size of the caps (2uF) will double the time.

http://runoffgroove.com/eatremolo.html

[gez]

How do you get this light mod that pulsates to the rate to turn off with the rest of the  pedal when switched off..And- how can you make the rale a little slower?

To slow the rate increase the 'stop' resistance connected to the pot or use bigger caps.

If you've built the ROG version then the only way you're going to get the thing to turn off when kicked out is to change the design.  A comparitor coming off the LFO output connected via a reverse diode to a MOSFET would give you a flashing millennium type thing...might not even need the comparitor (I've just woken up and haven't had time to think)  

[gez]

3PDT switch would sort it out.  Might be better to short out the 1k & 100k (pot) resistance chain than short the LED though (that way DC bias remains the same when kicked out).

[jimbob]

Ill giver a try- thanks.

[FatMike]

Hi,

can you also take electrolytic caps instead of normal ones?

I tried 2,2µF (electrolytic), but the light flashed somehow strange after that, as if the amplitude of the modulation became smaller and then bigger again. The light sometimes turned only a little bit darker instead of turning off, then after a while it behaved normal again. Quite strange.



Fat Mike

[dv8]

I used the 3rd lugs of the 3pdt switch to break between the neg side of the led and Q3.  But listen to Gez, he knows this circuit well.

Mine has no clicking on switch and the led flashes at rate, and this is the only indicator led I have.

[FatMike]

Is there maybe a way to switch the LED on/off using a 2PDT / Millenium bypass? Because I don't have any 3DPT switches at the moment.


Fat Mike

[gez]

Is there maybe a way to switch the LED on/off using a 2PDT / Millenium bypass? Because I don't have any 3DPT switches at the moment

Depending on how the collector of  Q3 biases up then it might be possible to connect a MOSFET millennium up to the LFO.  If you treat Q3's collector as though it were V+ then there might be enough voltage to overcome the MOSFET’s threshold.  Conversely, you might need to change the position of the stop resistor for the millennium’s LED from drain to source if the threshold is low - all depends on the individual MOSFET you use.

One way to help with biasing the MOSFET (if the voltage on the collector of Q3 isn’t high enough) would be to change the position of the LED and 10k resistor at Q3’s collector, but make the 10k a trimpot.  The wiper would attach, via a reverse bias diode, to the gate of the MOSFET.  The trimpot would help set DC bias of the MOSFET, but then less of the LFO’s output would modulate it.  

As I mentioned before, a comparator would help, the threshold could be set with a trimpot.  The LED would be strictly on/off though, no subtle change in brightness.  Then there's the problem of current spikes that this might introduce, layout would be crucial.  It’s the sort of thing I’d need to mess about with on a breadboard and, unfortunately, I simply don’t have the time.  Sorry…

It would be a lot easier to find a source of 3PDTs...

[gez]

But listen to Gez, he knows this circuit well

Actually, I've never built or breadboarded this circuit.

[gez]

I tried 2,2µF (electrolytic), but the light flashed somehow strange after that, as if the amplitude of the modulation became smaller and then bigger again. The light sometimes turned only a little bit darker instead of turning off, then after a while it behaved normal again. Quite strange

Probably leakage of the caps upsetting bias.  Either that or the slower charge up time of the caps meant that it took longer for things to settle down after switch on.  Who knows...

[puretube]

But listen to Gez, he knows this circuit well

Actually, I've never built or breadboarded this circuit.

nevertheless I`m missing you over at the small stones... :wink:

[gez]

nevertheless I`m missing you over at the small stones... :wink:

If I can find some time tomorrow I'll join in.  :oops: