Danelectro Cool Cat Vibe lag in effect

Danelectro Cool Cat Vibe lag in effect

--> OK, so its been a while since I posted but heres the mod for getting rid of the lag in engaging the effect and the pulsing indicator LED. The problem with the lag lies with the bulb in the vactrol unit - when you engage the effect it takes some time (OK, not much time, but enough to become annoying) for power to get to this bulb. When the bulb lights up, it pulses and feeds the four photo sensitive resistors arranged around it that work in the phase stages.

To achieve a more rapid effect-on state, were going to have to allow more juice through to the bulb to keep it in an always on state, meaning it takes less time for the thing to light up and pulse. The mod to do this is pretty straightforward with some careful soldering. See the pic below for reference. You need to solder a 10k resistor across the lugs shown in the pic on the bottom of the switch PCB.

The crucial mod - a simple bridging of lugs with a 10k resistor

As you can see, there are 6 lugs - we want to solder across the innermost two. Note Ive put the resistor inside some heat shrink tubing to make sure there are no shorts across the circuit anywhere else. Try it and test it, it works a treat! The other thing you get from doing this mod is a pulsing LED light - when the effect is off the LED pulses in time with the rate pot. When you engage the effect, the indicator LED remains on as normal. Job done.

I also removed the indicator bulb, wired in two long wires to attach to the new bulb. You can see this in the pic below. Just make sure you wire up the anode and cathode legs of the bulb in the same way as the bulb you just removed. To test which is which on your LED, you can use a multimeter that has a diode function - it puts out a little power for you to fire up a bulb without the need for a protective resistor. Do this on the original bulb in place and make note of the anode (the positive leg) and the cathode (negative leg).

Alternatively remember the FAT FLAT CAT mnemonic which indicates polarity of an LED. Hold the bulb up to a light you should see two metal blades inside, one thin and one much wider. The wider element is the cathode (negative pole). If you can distinguish a flattened side to the LED casing then this also indicates the cathode part. FAT: fat blade. FLAT: flattened edge to LED case CAT: the above two point to the cathode negative leg. Flip the board over on the underside you can see the schematic symbol for a diode. The flow from positive to negative goes through the triangle and exits at the vertical line. This line represents the negative cathode side.

Remember I also said I would replace the small bulb in the vactrol with a larger red LED? Yeah, well I did this and I wouldnt recommend it unless you really know what youre doing (and I dont)! Although the bulb puts out more light and still fed the photo resistors nicely, it still suffered from the lag in engaging the effect and the above mod didnt help out. Even trying different values of resistor to allow more juice to bleed through to the LED didnt help. Back to the drawing board on that one! Im going to take it out and replace the original bulb, after all, why mess with something that works perfectly well in the first place? Thats the problem with me though - I cant leave things alone and feel the need to tinker and fiddle about when I should just walk away!

Just for the heck of it, heres the pic of the new bulb in place and fired up. Quite an overkill compared with the original clear lamp. The super brightness of it drove the resistors in a more powerful way giving a different phasing effect, so I compensated by turning down the internal trimmer to lessen the intensity a little. Im not going to bore you with pics of enclosures and housing this yet.

The new LED - plenty of light but not the best option IMHO

Danelectro Cool Cat Vibe lag in effect