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Kasino amp occasionally makes strange noises

Started by LJN, November 29, 2015, 06:38:56 AM

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LJN

Hi, everyone. That Kasino amp is still working, but occasionally makes odd popping sounds through the speaker. I have pulled it apart several times because the old solder kept coming loose in the power section, and there was some corrosion that had to be cleaned out. Is it normal for these amps to make the occasional odd noise, or do I need to start working on it again?
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

Enzo

You need to determine where the noise is coming from.  The amp may have a part breaking down, it may have a weak connection.   But it could also be outside the amp.  Cell phones sitting on amps often make noises in them.  Power line noise also can come through.  The motor in your furnace may be coming on and off, or a sump pump motor.  Switching transients on the mains could be the cause.  Etc.

Tune an AM radio between stations so you only get hiss, leave the volume up on it.  Now, when the amp pops, does that radio also make noise?   it can pick up radiated noise from sparking contacts.   Doesw the amp still make pops if you plug it in at someone else's house?

I had an amp make occasional buzzing noises for a few seconds about once a minute.  drove me nuts trying to figure it out.  By luck I happened to see the traffic light at the end of the block changing colors, and realized my amp made the noise precisely whenever that traffic light was yellow on one direction.  Apparently a noisy triac in the control box there.

phatt

 :lmao: Yep,,, stuff like that can really test your sanity. :duh
While working on a really hi gain circuit I wondered where the ticking sound came from. Drove me nuts until it dawned on me that my watch was being picked up. Bangs head against wall while saying ,,why did I miss that xP
Phil.

Enzo

I had to replace my bench phone, and got a wireless AT&T unit with answering.  I discovered that now any sensitive circuit within a foot and a half picks up a digital whine.

LJN

Thanks for your suggestions.  I have never taken the amp anywhere, so I don't know how it would act in another house. There was one night when it started making those noises and I determined it was picking up interference from one of my antique fans. Lately,  there's been a faint buzzing noise that comes in after the amp has been on for about 10 or 15 minutes. Could that possibly be some kind of interference. We don't have a working furnace anymore, either, but we do use a submersible well pump. My brother also keeps an air conditioner running in his bedroom, which is less than 20 feet from where the amp is sitting. Thanks again.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

LJN

I should also say that I don't live near any traffic lights, or anything like that. I live away from the city on a mountainside. Unless it's coming from the transformer outside, or the well pump, I don't see much anything else that would cause the interface.  I also try to keep my phone at least a few feet away from the amp. I'm really at a loss here.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

Enzo

Mains noise can travel miles on the wires.  Well pumps certainly are local, but the next farm down the road could be polluting the power line.  Farmers who have fencers sometimes make sparks.

But that is why I suggested the AM radio trick.  hell, wrap a couple turns of the power cord from a table lamp or something around it.  If it picks up the pops, you may have power line issues.  If it doesn't the power may be innocent.

There are plenty other possibilities.   A poor grounding of the power transformer bolts for example, COULD allow static to build up and occasionally discharge.

J M Fahey

Usual disclaimer applies:
Kids, don't do this at home.
I have scoped mains to find interference/noise/buzz/chirps  :loco

And yes: it's *dirty*   :(

Worst offenders are brushed electric motors (hand drills/shavers/hand grinders/many kitchen appliances/some garage door openers/etc.) which are sources of buzz and stuff going on/off , hugely inductive loads such as fridge/AC/washing machine/etc. motors, which are sources of thump/pop/click sounds.

Not forgetting SMPS and their sharp spikey waveforms.

As Enzo said, they can travel for miles along mains wires, and radiate like antennas to molest even unconnected, battery powered stuff.

Plus ubiquitous cell phones, I can't put mine within 1 ft from the very notebook I'm writing this on, because I hear it through the "200W" USB powered PC speakers.


LJN

Thanks, Juan. So, those antique fans of mine could be causing some of the noises in my amp? That's a shame. I guess I'll just have to live with it. I haven't noticed anything else that could be causing it.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

J M Fahey

Mains powered fans are usually powered by some kind of brushless induction motor, so I wouldn't suspect *them*  .

That said, any brushed motor is a noise factory.

LJN

Okay. Thanks again, Juan. I had been wondering if my old fans could be contributing, but maybe that's not the case. Could it be fluctuations in the mains voltage? I have come to suspect this by paying close attention to my vintage fans while running them. Also, there are times when the light in my room either dims or gets slightly brighter. I keep this amp plugged into a surge protector, but I don't know how much protection that actually offers.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL

LJN

I've still been using the amp with no problems other than a mild hum. I played through it for over an hour earlier. I wonder where that hum is coming from. I don't think it's the filter caps because it seems to go away when the volume is turned down, I think.
If it sounds good, USE IT!

Epiphone Les Paul, Kasino U100- P, Sears 125-XL