King Nothing High Frequency Noise

[Falterthethomist]

Hi everyone, I built a King Nothing a couple of weeks ago, and it sounds great. However, I only recently noticed that when firing it up, there is a loud high frequency noise for about one minute, then it disappears. I am assuming it has something to do with the filaments heating up, but I am not sure. I haven't noticed similar issues on other C2CE builds like the ambassador or diplomat.

Is this something I need to worry about? As I said, it works great a minute after powering it.

Thanks, Markus

 

[vigilante398]

Hi everyone, I built a King Nothing a couple of weeks ago, and it sounds great. However, I only recently noticed that when firing it up, there is a loud high frequency noise for about one minute, then it disappears. I am assuming it has something to do with the filaments heating up, but I am not sure. I haven't noticed similar issues on other C2CE builds like the ambassador or diplomat.

Is this something I need to worry about? As I said, it works great a minute after powering it.

Thanks, Markus

My first question when people ask about noise issues is and always will be, what power supply are you using? It sounds like it may be an issue of the tube taking a while to heat up, and it is fairly normal for there to be noise and artifacts present while the tube is warming up.

 

[Falterthethomist]

It is a standard 9v supply, I think it came with a Zoom pedal. I never had any issues with it. It also works fine with the other tube pedals.
I'll hook the King Nothing up with my dedicated pedalboard supply and will report whether it makes a difference.

 

[vigilante398]

It is a standard 9v supply, I think it came with a Zoom pedal. I never had any issues with it. It also works fine with the other tube pedals.
I'll hook the King Nothing up with my dedicated pedalboard supply and will report whether it makes a difference.

The thing I'm concerned about is supply current, you're going to want a bare minimum of 400mA, but the more the better, and the less you have the longer it's going to take the tube to warm up.

 

[Falterthethomist]

The thing I'm concerned about is supply current, you're going to want a bare minimum of 400mA, but the more the better, and the less you have the longer it's going to take the tube to warm up.

It is 500mA. Do you have any idea why your other pedals don't behave the same? Could it be a cold solder joint somewhere in the Smps network? Even the Ambassador is working well with the same power supply, and it needs to heat up two 12ax7s.

 

[vigilante398]

It is 500mA. Do you have any idea why your other pedals don't behave the same? Could it be a cold solder joint somewhere in the Smps network? Even the Ambassador is working well with the same power supply, and it needs to heat up two 12ax7s.

If it's not doing the same thing on others then I would definitely start to look for issues in the board, solder joints around the SMPS and around the tube itself are a good place to start.

 

[Falterthethomist]

If it's not doing the same thing on others then I would definitely start to look for issues in the board, solder joints around the SMPS and around the tube itself are a good place to start.

I'll do that. Thanks for your advice, I really appreciate it. I'll report back whether I find the issue.

 

[Falterthethomist]

Hi there, so I did reflow all the solder joints and checked for continuity - but i can't really find the problem. The voltages on the plates of the 12ax7 and the heaters look good too.

I noticed some funky things though yesterday:

If I power up the pedal without being connected to the amp, you can hear the high frequency noise emanating from the pedal - when I plug it in the noise just gets amplified by the amp - in bypass as well as when it is on.

This makes me think that the problem is not in the signal path but might be related to a "hardware issue." I already swapped out the ne555 without any effect. Any ideas which part could be responsible for the noise? the IRF740? Or the inductor?

As I said before, the noise disappears after 1-2 minutes, and then everything is working fine.

The noise is also present when i power up the device without the tube - which kind of rules out the heaters?

Thanks again, any help is greatly appreciated.