occasional popping sound

[dsavitsk]

My BrianGT Rev 2 amp has been up and running for a few hours. I am noticing that is makes a popping sound every once in a while -- like every 20-30 minutes -- that sounds like when one touches a volume knob with static electricity. It is very quiet -- only noticable when the amp is on but not playing anything -- so it doesn't seem like it would be damaging. Has anyone observed something similar?

-d

[neutron7]

do you think it could be when an appliance such as a refrigerator or furnace fan turns itself on or off? in which case it will do no harm except to annoy you

[dsavitsk]

I think there is a good chance that this is it. I have horrible power here. I figured I'd ask, however, as my other power amp doesn't do this. It is a commercial product, though, so there may be some built in protection.

-d

[jeff mai]

On my BrianGT board amps, the one built using the transformer without the electrostatic screen makes these pops, the one with the screen does not. Unfortunately you can't add such a screen after the fact as it is between the windings. You have to ask for it from the manufacturer.

Others may say that the noise couples through the air via RFI, but I suspect that in most cases it sails right through the power supply. In these amps there isn't any series supply impedance to damp them.

If it really bugs you and you can't have an electrician fix the source of the spike, you could try adding some series impedance to the amp's power supply (choke or resistor) to damp the spike.

[chris ma]

There are some capacitors that have a build in resistor that I used across the secondary windings or at the bridge rectifier to supress things (spike) like that. I am not sure it work for me or not since I do not have any problem in the first place but I include them just to be safe. My ones are the RIFA EMI supression caps it has a marking of 0.47uf + 22R on the top of the cap and rated at 600ACV I think.. can confirm tonight if needed.

The Butcher

[Nuuk]

Another possibility is a poor solder joint!

[Sherman]

It does sound like a power spike rather than RF. There was a thread here started by Kofi Anan re: bad power in his house. His fix was a $50 surge supressor with voltage regulator from Best Buy. It will kill spikes and regulate voltage (high and low). He reports total relief from power problems.

However, when the regulator/suppressor circuit is activated the device itself makes a small click which may be equally annoying in your case. (His issues were much worse and the little click was welcome relief.)


You may also just try a decent surge suppressor and see if it helps.

(oops, forgot that thread was in the "Tube" section if you go looking for it.)