[SOLVED]High-pitched popping sound in R channel

[mtheshark90]

Found the problem. Amazingly enough it never occurred to me that my phone, which normally sits about 4 ft away, was causing the issue. Never had this problem prior to speedball, maybe the amp became more sensitive to it after the installation.

--old problem--
As the title states, I'm curious if it's normal to hear a static popping type sound through the headphones after turning on the crack for the first 2-3 minutes. I never had this issue until I installed the speedball. It only happens right after turning on the amp, occurs for usually 2 minutes then disappears, and occurs at ALL volume levels.

Is this normal?

I'll note that all voltage checks were normal after installation.

 

[Paul Birkeland]

You may have a solder joint that isn't quite 100%, I would look over the amp and reheat any suspicious joints.

Another test people do is to wear a cheap set of headphones with the amp running upside-down.  Next you can poke around the amp with a wood chopstick to see if you can create the static by disturbing a specific joint.

-PB

 

[mtheshark90]

Ok, so I'm coming back to this thread 2 months later with an issue that's driving me crazy.

As per my original post, my crack began having static issues sporadically in both channels, and always during warm up. This began after the speedball was installed.

So I did the chop stick test and found a joint on a capacitor that went ballistic if poked, so I decided to re-flow that. It seemingly fixed the static, but a new problem arose....there was occassional high-pitched static that resembled extremely rapid popping in the R channel, which does not occur upon warmup and only lasts 3-5 seconds at a time. It occurred infrequently as well, maybe once in 10-20 minutes.

So I decided to re-flow that joint AGAIN, this time by someone with far more experience than me.

Disappointingly, the same problem persists, but it now seems to be even less frequent..maybe once every 20 minutes or more (though I haven't extensively tested it since the repair so it may as well be exactly the same.)

Are these symtpoms typical of a bad joint? Is there any reason it would now suddenly be isolated to the R channel? Any suggestions for further testing?


Also for what it's worth, if I slap the side of the amp while it's making the noise, it sometimes makes a loud pop and resolves. And if the tube is jiggled while the amp is on, it will always make loud popping and static.

 

[denti alligator]

I had a similar problem that ended up being the tube.

 

[mtheshark90]

Hmm perhaps I'll just get a replacement tube and see what happens. The unusual thing is, before the speedball installation I had no problems for a month straight.

 

[Deluk]

Clean the tube pins before you buy another. Do a proper job on them. When fitting the Speedball you likely had the tubes out and refitting them may have compromised the pin connections.

 

[mtheshark90]

EDIT---problem solved. My phone was the culprit this entire time. Perhaps the speedball upgrade made the amp more sensitive to it. I now keep my phone ~5 ft away and no problems.

Alright, bit of a breakthrough here -- just now decided to play with the volume knob whenever this annoying sound occurred. While the strange high-pitched popping doesn't get louder or softer with volume control, I did notice that if the knob is maxed out the noise cuts from the R channel and becomes very faint in the LEFT channel. What the?

Similarly, if the knob is turned all the way down, the noise cuts out completely. But anywhere in between min-max the noise will occur.


I do have an alps blue velvet for my potentiometer, so I guess I'll take a look at the connections tonight to see if any joints aren't quite 100%. Other than that, I'm really stumped by this one.

 

[Paul Birkeland]

Alright, bit of a breakthrough here -- just now decided to play with the volume knob whenever this annoying sound occurred. While the strange high-pitched popping doesn't get louder or softer with volume control, I did notice that if the knob is maxed out the noise cuts from the R channel and becomes very faint in the LEFT channel. What the?

Similarly, if the knob is turned all the way down, the noise cuts out completely. But anywhere in between min-max the noise will occur.

You may just be tuning a resonant circuit, I wouldn't read too much into that.