3pdt-05 board -9 problem

[cspar]

I recently build 2 pedals something akin to a EQD Dirt Transmitter only with trimpots for both collectors and the shunt feedback resistor as well as a switch to swap the caps between the emitters.

I've got Russian Germaniums in both. One pedal is +9 NPN and the other pedal is -9 PNP.

On the -9 one I used a 3pdt-05 RoadRage charge pump on a footswitch board from the shop. I used a Max 1044, the jumper and the correct diode for the chip.

I works first off but then somehow the charge pump stops working.

The only thing that I can think of is that maybe charge pump's don't like how I have the jacks wired. I currently have both input and output wired so that the jack grounds when there is no plug in the socket.

Is this what's blowing my charge pumps?

[cspar]

This morning I switched out the jacks and put a new charge pump in the socket.

Same PSU. Same everything else including trying it before a Pitch Pirate that I've been swapping ldr/leds with my RoadRage based proto/breadboarding unit.

The new Max 1044 has survived everything that I've done so far. Third time seems to be the charm.

So is using the hardware jack switch for grounding in conjunction with a charge pump and a latching 3dpt something that you just can't do?

If so perhaps a word of warning should be written into the 3pdt-05 and RoadRage pdfs.

[matmosphere]

you just have to be super careful with Max1044's. In my experience 9 volts is fine but 10 volts (maybe even 9.5) and they just stop working. If you have a multimeter check and see what your power supply is putting off. If it's getting above 9.3volts then it might be the issue.

I think 1044's and 7660's are intended for 5 volts, not 9 and that is why they don't always work well in pedals.

[cspar]

Thanks for the tip Matmosphere.

I use a San June red PSU brick and the 9v outputs vary from 9.1 to 9.48.
Not really sure which port I used before but I'm gonna mark the lower ones as my charge pump ones.

[Boba7]

I've seen an old MXR unit that delivered 10v instead of 9. And Ive read somewhere about some units producing random voltage spikes.
Anyways, I'd use tc1044s (max input voltage 12v)  or lt1054 (15v) instead if it happens again!

[cspar]

Sadly the datasheet for the Max1044 says that the max voltage is 10.5v.

I think that the best thing for me to do is remove the jumper, swap the diode and replace the Max1044 with a LT1054.

I'm glad that's what I used on both of the RoadRage testing units that I've built. Even though I never really use the 15v jack.

If my first one had failed it would have been a big hurdle in my early breadboarding.

After this I don't think that I'll buy another Max1044. Seems they're too problematic.