Pops clicks and buzzes

Konzentr8

Member
2015-08-05 11:17 pm
This question shows my total lack of knowledge but would appreciate an answer .
I have just got a S.M.S.L SA 50 and during instalation i connected the speakers using banana plugs then for testing purposes i plugged a cheap 3.5 mm jack - L/R rca lead into the amp ( rca 's at the amp end ) with nothing connected as yet to the mini-jack.
Double checked all connections etc then attached the 24 v psu plugged in and turned it all on,still with nothing connected to the input other than the lead.
As soon as the volume was moved from zero there was a loudish background hum though the speakers which was reduced slightly by touching the amplifier casework. I then went to plug my phone in to the input cable and when touching the cable loads of loud buzzing and pops as it was moved and touching the metal of the jackplug produced lots of distortion and very loud clicks.
Once the cable was connected to the headphone socket on the phone all noise disappeared completely and touching or moving the cable did not result in any more issues.
I would imagine this is elementary stuff to the majority of people here but i am concerned that all the initial noise may have damaged the amp ? and would be grateful for any responses , thanks in advance.
 

Konzentr8

Member
2015-08-05 11:17 pm
Bump ... i know this is probably simple stuff and down to earthing etc? but i'd really like someone to explain why this happened and more importantly would it have damaged any part of the amp also i noticed when its turned off theres a small delay and the led around the volume fades slowly and then a click but the click is only noticeable on the right speaker .
 
Some noise from an unterminated input is not too surprising. It may indicate that the input cable was poorly screened - these days copper is so expensive that really cheap unbalanced cables are not actually screened but are more like loosely twisted pair. The noise probably won't have damaged the amp. Speaker damage is more likely.

A click on turning off is not surprising. The slowly fading LED is not surprising - it just means that a capacitor is discharging.
 

Konzentr8

Member
2015-08-05 11:17 pm
Some noise from an unterminated input is not too surprising. It may indicate that the input cable was poorly screened - these days copper is so expensive that really cheap unbalanced cables are not actually screened but are more like loosely twisted pair. The noise probably won't have damaged the amp. Speaker damage is more likely.

A click on turning off is not surprising. The slowly fading LED is not surprising - it just means that a capacitor is discharging.

Thankyou for your help. It was a really cheap cable i just use for quick hook up and testing i don' t think it has any shielding whatsoever i was just surprised at the amount of distortion just from touching it .