SV20C issue

[FredB98]

Hi all,
I need some help.
I just got my brand new SV20C yesterday. Immediatly after i plugged in, i noticed a sort of hummm sound when i turned the "High Treble/Loudness I " button. It is a sort of white noise.
I unplugged everything, and the noise was still there.
Any idea where it should come from ? Should i send it back ?
Thanks !

Fred

 

[ken361]

White noise is normal though for a plexi though. The hum not so could be a tube. Could try moving them around and see what happens.

 

[Central Scrutinizer]

Welcome to the forum @FredB98 !

Agree with Ken above.

In transit sometimes the tubes loosen. Turn off and unplug the amp and check tightness of the tubes at the least.

Good luck.

Keep us posted.

 

[scozz]

Yes, agreed about a tube possibly coming unseated, I would re-seat them all if it were my amp. Unless you’re uncomfortable doing that, I don’t know your experience level.

As far as the “white noise”, as you put it, goes, plexi’s are known for some of that as @ken361 said. Are you able to post a video showing us how bad it is?

 

[marshallmellowed]

Hi all,
I need some help.
I just got my brand new SV20C yesterday. Immediatly after i plugged in, i noticed a sort of hummm sound when i turned the "High Treble/Loudness I " button. It is a sort of white noise.
I unplugged everything, and the noise was still there.
Any idea where it should come from ? Should i send it back ?
Thanks !

Fred

Sounds like you're referring to the same sound as hum, and then white noise. "White noise" is normal with high settings of the High Treble. Hum is not normal, if you actually have "Hum".

 

[FredB98]

Thanks all.

Here's a short video of the problem :

My level of re-seating the tubes is beginner buut i can try

 

[FredB98]

Yes, agreed about a tube possibly coming unseated, I would re-seat them all if it were my amp. Unless you’re uncomfortable doing that, I don’t know your experience level.

As far as the “white noise”, as you put it, goes, plexi’s are known for some of that as @ken361 said. Are you able to post a video showing us how bad it is?

Thank you for your answer.. Here's a short video.

 

[Dogs of Doom]

hiss is normal... do you know how loud your guitar will be at that volume?

LOUD!

 

[Ramhead]

Sounds like a highly microphonic preamp tube

 

[Gene Ballzz]

@FredB98

FIRST> to the forum and the life of fantastic Marshall sounds! And HNAD!

I hear no "hum" in the video, just the hiss that is fairly normal for this amp at that setting. Some tubes "might" be a little less hissy, but likely won't sound quite as nice when playing. An as metioned, your guitar would be loud as sin at that setting! Mine hisses like a snake, when not playing, but stings like a bee when I want/need it to!
Enjoy Your SV20C,
Gene

 

[Old Punker]

As others have pointed out, that hiss is normal for a tube amp cranked up like that. Some will have a higher/lower noise floor than others. I've heard some that sound like a wind storm when turned up while idle. You wouldn't hear any of that while playing, and if you're playing a gig somewhere, the background room noise would drown out any hiss, even if you could have your volume up really high. And while playing at home, most would not have their amp at that level anyway.

 

[Cal Nevari]

Hi all,
I need some help.
I just got my brand new SV20C yesterday. Immediatly after i plugged in, i noticed a sort of hummm sound when i turned the "High Treble/Loudness I " button. It is a sort of white noise.
I unplugged everything, and the noise was still there.
Any idea where it should come from ? Should i send it back ?
Thanks !

Fred

Welcome to the forum and happy NAD! That hiss is pretty common with the SV20C. I sold mine because I just couldn’t get used to it. But other folks here love them. It’s all down to personal taste.

 

[scozz]

Thank you for your answer.. Here's a short video.

That’s sounds normal to me.