Sound coming out of amp head (jvm)

6up8Vx7u

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Hello, I'm new to the forum and this is my first post.
I have recently bought a jvm410h and it's connected to a reactive loadbox.
When the speakers are muted, I can hear fizzy sound coming from amp head as I play. As I turned up the volume from the amp, the sound becomes more audiable, it is like a distorted guitar sound from directly from amp head.
My question is, is this a problem? How the amp is making this sound? Sorry if this is a silly question.


Thanks.
 

RLW59

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Magnetostriction.

The rising and falling magnetic field in the output transformer causes physical dimensional changes in the laminations of the transformer.

The laminations aren't great transducers so the volume is relatively low, tinny, kinda distorted.

All transformers do it to some degree. The power transformer makes a quiet 60hz noise (or 50hz in countries that use 50hz AC). The output transformer's magnetic field is related to the audio signal passing through the transformer so it matches the audio signal (in a very lo-fi way).

Some output transformers are louder than others. And how they're mounted can amplify the noise.

People who don't do silent recording into a load box will never hear it because the speakers normally drown it out. And because some transformers are louder than others, even people who use a load box may not hear/notice it. (Plus silent recorders are often wearing headphones.)
 

crossroadsnyc

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Oh man, this thread title freaked me out ... I was afraid you were wondering why sound wasn't coming out of the head, maybe not realizing you needed a cabinet as well! Phew!

Lol, reminds me of that picture that use to float around where someone placed the microphone up against the head rather than the speaker in the cabinet.
 

Tatzmann

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Magnetostriction.

The rising and falling magnetic field in the output transformer causes physical dimensional changes in the laminations of the transformer.

The laminations aren't great transducers so the volume is relatively low, tinny, kinda distorted.

All transformers do it to some degree. The power transformer makes a quiet 60hz noise (or 50hz in countries that use 50hz AC). The output transformer's magnetic field is related to the audio signal passing through the transformer so it matches the audio signal (in a very lo-fi way).

Some output transformers are louder than others. And how they're mounted can amplify the noise.

People who don't do silent recording into a load box will never hear it because the speakers normally drown it out. And because some transformers are louder than others, even people who use a load box may not hear/notice it. (Plus silent recorders are often wearing headphones.)

Ever had a JCM2000?

You flip the standby and feel the vibes!
 

Dogs of Doom

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Hello, I'm new to the forum and this is my first post.
I have recently bought a jvm410h and it's connected to a reactive loadbox.
When the speakers are muted, I can hear fizzy sound coming from amp head as I play. As I turned up the volume from the amp, the sound becomes more audiable, it is like a distorted guitar sound from directly from amp head.
My question is, is this a problem? How the amp is making this sound? Sorry if this is a silly question.


Thanks.
Hi,

:welcome:to the forum...

is there a way you can make a video & put it up on youtube or similar? & post it?

That would help immensely.

:cheers:
 

Calebz

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Hello, I'm new to the forum and this is my first post.
I have recently bought a jvm410h and it's connected to a reactive loadbox.
When the speakers are muted, I can hear fizzy sound coming from amp head as I play. As I turned up the volume from the amp, the sound becomes more audiable, it is like a distorted guitar sound from directly from amp head.
My question is, is this a problem? How the amp is making this sound? Sorry if this is a silly question.


Thanks.
This sounds like normal behavior.

When I bought my captor, there was even a mention of this phenomena in the quick start guide.
 

6up8Vx7u

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Magnetostriction.

The rising and falling magnetic field in the output transformer causes physical dimensional changes in the laminations of the transformer.

The laminations aren't great transducers so the volume is relatively low, tinny, kinda distorted.

All transformers do it to some degree. The power transformer makes a quiet 60hz noise (or 50hz in countries that use 50hz AC). The output transformer's magnetic field is related to the audio signal passing through the transformer so it matches the audio signal (in a very lo-fi way).

Some output transformers are louder than others. And how they're mounted can amplify the noise.

People who don't do silent recording into a load box will never hear it because the speakers normally drown it out. And because some transformers are louder than others, even people who use a load box may not hear/notice it. (Plus silent recorders are often wearing headphones.)

I don't know a lot about magnetic fields. Are you saying that depending on environment that amp is in, there can be different magnetic fields and sounds coming from amp head?
Because the amp tech has checked it, and there was no sound. So probably some other interference at home.
 

6up8Vx7u

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Oh man, this thread title freaked me out ... I was afraid you were wondering why sound wasn't coming out of the head, maybe not realizing you needed a cabinet as well! Phew!

Lol, reminds me of that picture that use to float around where someone placed the microphone up against the head rather than the speaker in the cabinet.
Cabinets?? What are those?? 🤨
 

Calebz

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Do you also have the same problem?

If the sound you're talking about is the little tiny background noise (behind the acoustic string noise), then yes - I have it when using my load box. It doesn't come through on DI recordings though. And as it is part of the normal operation, it isn't a 'problem'.

What make/model of load box/attenuator are you using?

From the Two-Notes website:

3. Is the use of a loadbox totally silent?​



We usually talk about “silent recording” when a loadbox is involved. If we compare the loadbox solution to a traditional cabinet miking solution, it is obviously several orders of magnitude quieter, but you will still experience some minor sounds, noises, that have to be taken into account:
  • Your guitar or bass strings can be heard. This is obvious, but it can be disturbing, depending on your environment.
  • You may hear some noise coming out of your Torpedo when playing, like there is a tiny speaker inside the box. This is perfectly normal and there is no reason to worry. The sound is produced when power goes through the coil of the reactive load embedded in the Torpedo Captor. The vibration is related to what power comes out of the amplifier connected to the Torpedo and to the signal’s frequency content (notes played are heard). Your amplifier may also produce similar noise, at the output transformer’s level. Such noise is usually not heard, simply because it is normally overcome by the sound coming from the loudspeaker.
  • The Torpedo Captor embeds a fan, as there is quite a lot of power dissipated into heat inside the box. We selected a so called “silent fan”, but as it is running fast, it is never entirely silent. This said, you can consider that, in normal use (hearing your guitar through monitors, or headphones), you can barely hear that fan.

By the way - how much did the amp tech charge for the visit?
 

6up8Vx7u

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If the sound you're talking about is the little tiny background noise (behind the acoustic string noise), then yes - I have it when using my load box. It doesn't come through on DI recordings though. And as it is part of the normal operation, it isn't a 'problem'.

What make/model of load box/attenuator are you using?

From the Two-Notes website:



By the way - how much did the amp tech charge for the visit?

When the sound is at full volume, it is really loud and scary :)
I guess it's not going into recordings. But it makes me think that something wrong with the amp or there is some kind of interference that I need to fix.
I'm using ua ox box 16ohm.
He didn't charge at all :)
 

scozz

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I have never heard about this phenomenon, I can understand how it might freak someone out a bit. :)
 

JPnosweat

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Did you try the direct line out from your amp backside ?
If he(it) still has the same noise you can be sure it's in front of the amp, guitar, cable, maybe some bad earth connection on your power suply...
 

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