Pop Supression on 2 Stroke

[djroge1]

Ok thanks for the replies. This is the first I’ve had to sit down today – Sunday’s are my busiest days.

No I’ve not had time to trace the signal. But it seems like my voltages are right in line with others here so that’s good.

Actually, I made some changes to daves design. Specifically in the mini-switch. As you know, the original design made a “pop” when switching. In my first 2 stroke some of us on the old TAN forum came up with some resistor values and where to replace them to get rid of the pop. Well, I forgot to make notes so I don’t think I have that section wired correctly.

I may need to put it to stock as per dave’s design and then work on fixing the pop.

Oh, and I double checked the ground on V1 last night.

[M Fowler]

To eliminate pops on switching use a 4M7 resistor from switch to ground this will stop that annoying pop.

Mark

[Robin]

The “Maggie layout from Weber shows the “Boost” switch with “pop stopper”
resistors installed. https://taweber.powweb.com/store/maggie_layout.jpg
Considering what many of us have paid for parts to build a 2Stroke, the Maggie kit seems like a good value. I’ve had very good service from the Weber transformers.

[M Fowler]

You only need one resistor a 4.7 meg from the center of the switch to ground to stop the pop. Also you only need a spdt on off on switch not a dpdt like weber shows.

Not sure why weber does it like that kind of unusual.

[Robin]

Mark, I tried the “one resistor across the switch” at first and could never get it to resolve the pop. The only thing that worked was one resistor on each side (for each cap). Perhaps I was wiring it incorrectly, but after it didn’t work as I expected, I tried it several ways with no joy until I went the 2 resistor route. Can you explain how to make it work with one resistor?

[M Fowler]

The capacitor stores a charge and when you flip the switch it sends the current to ground causing the pop. To suppress the pop you use the 1m resistor to ground in the Maggie option.

The pop occurs in the switch so you must need the resistor directly off the end of the cap to center lug to prevent the cap discharge pop.

Not totally sure why a 4m7 resistor from center of switch to ground wouldn’t stop the pop verses using two separate 1m resistors.

I included a bright switch off volume pot if anyone want to use one. This is a two way and use what ever value silver mica cap you want to use. Or other types of caps.

[djroge1]

I got her up and running. I’m trying the 4.7m resistor from center of switch to ground to see if that gets rid of the pop.

On my last 2 stroke I did it the way Robin talked about – one resistor going to each cap. I cannot remember the values though. That way worked like a charm.

[djroge1]

I’m visiting this again because i’m just now getting around to fixing the pop issue (I’ve been waiting for the cab to arrive).

Once again I’ve gone the two resistor route to fix the pop. 4.7M to the .47uF and I places a 1M with the 25uF but it still pops. I’ll try a higher value and see what happens.

[M Fowler]

The 25uf boost or bypass cap is the larger of the two and holds the largest voltage in storage causing the pop so I would start with the 4m7 resistor on that larger cap.

[djroge1]

yeah me thinks me did it backwards – you are correct. I ended up placing a 390ohm on the 25uF and it suppresses the pop.

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