Helder TA2020 MKII Start Up Pop
 

Hello,

I have roughly assembled a Helder Hifi TA2020 mkII board and I am getting quite a large pop when I power it on as well as some humming when I touch the volume pot. It's not a metal box at the moment, that's going to change soon. I read some threads on on/off pop but there didn't seem to be a consensus on how best to fix it.

I am an utter noob on amplifiers and electronics so any advice would be greatly appreciated. If posting a wiring diagram would be helpful please let me know.

Kyle

First you need to find out what ius causing the pop.
It could be arcing on the mains switch or just the amp settling down on power up.
A small capacitor across the switch will get rid of arcing.

If its a single pole switch then across the switch terminals.
Instead of the switch arcing the capacitor soaks up the arc.

Ah, okay. There are some caps sitting around I can use. Any rough guide for a minimum?

KM

Try a 10nF to start with.

It's probably caused by the large input caps, and there's nothing to do about that unless it has a mute switch, in which case you mute it while powering on and off.

Hi Nigel and Saturnus,

I will try and take a look at those tonight. The amp's description mentions muting and sleeping, I'll have to take a look and see if those are exposed tonight. I'll let you know how it turns out. The amp is directly connected to some EL70 drivers, no crossovers. The cones move in and out quite a bit when powered up, and there is very slight delay after I throw the switch, so, perhaps it is the input caps.

Thanks,
Kyle