Urgent, my new and first amplifier might be broken

Hey guys, i just got my amp delivered to me an hour ago and its making this white noise or humming or whatever you call it.
Is it normal? And a loud noise when i turn reverb high. Watch both videos pls. https://youtu.be/2J1j1sSp1aM?si=kQhM-ebywGRq9Npe

The hiss is not uncommon, but expected at very high gain settings. I can’t really tell how loud it is in the room, but given the settings, I’d think you could talk at a normal volume and not have it overwhelm the conversation.

The reverb generating an oscillation is not correct. This suggests gain is pinned at full somewhere in the chain and you are getting feedback, but that’s just the engineer in me thinking about possible problems.

I did find the following reddit that someone else has seen two with this same problem: Reddit - Dive into anything . These folks are not knowledgeable about the guts of the amp, but it does suggest it is a common problem.

I doubt it will change anything, but unplugging the guitar cable might be a good experiment. If it changes something, then plug back in and try turning down the guitar volume and see if that also lowers the hiss. The reason I don’t think this will change anything is because it does sound like thermal noise from a lot of gain, not the usual mains hum or environmental noise from a single coil pickup. Of course this test may be just a curiosity because I suspect you will be returning this due to the reverb oscillating.

It could be the amp, the guitar, radio interference (via guitar) or an unclean power feed.

The hiss in the first video is odd, given the gain is set to 0. But without being in the room, it’s impossible to know if it’s unusually loud or just normal solid-state amplifier hiss.

The tone in the second video is almost a perfect F note. Weird. That’s definitely abnormal. Could be the reverb circuit oscillating as suggested by @sequences.

Are the noises the same with the guitar lead unplugged from the amp?

It’s even more odd if you consider the amp is in the clean channel (green light on indicates clean channel, if it was on the dirty it would be a red light instead of a green). In the clean channel I’d think the amp should be hiss-free.
I’d return it.

Clean does not mean hiss-free. it simply means really low distortion, even when gain set high.

You will still get what we call “thermal noise” from any amplifier be it clean or not. If you have enough gain, and I mean amplification, not distortion, then you will get hiss noise at the speaker.

ok, so what did I mean by the gain=amplification not distortion? The guitar player crowd has been calling “gain” = “distortion” on amps. While you need to increase gain to get distortion, the proper way to think of gain is that is it simply making a signal larger, and usually it does not involve making much different - i.e. keeping it clean. the distortion is coming from the various gain stages being pushed too hard creating a change in the output beyond just making the input bigger. Engineers call it overdriven, and it is related but not the same concept as “overdrive” in the guitar player community.

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That’s a very nice and helpful explanation Michael, thank you for that!
I’m, by and large, familiar with the concept but I love good explanations such as this.

My comment was mostly motivated from my own experience with the amp which in the clean channel doesn’t make much noise (unless I play the guitar :rofl:).
I uploaded a video on the clean channel with the gain up, channel volume up and master volume up too. Most of what you hear is ambient noise, nothing like what Avleen’s amp does.

I would argue it is, at least at it’s core. Overdrive, on analogue guitar amps, is when the pre -amp stage is driven into soft clipping.

Since then there are guitar pedals that emulate or recreate this. But the principle is the same.

“Distortion” is a lot more vague and can, technically, apply to anything from a mild overdrive to a heavy pedal-based diode clipping, or even a speaker with a torn cone.

But it usually tends to apply to more deliberate, artificially generated, more distorted (often called “higher gain”) tones.

And you are spot on with the gain definition.

Cheers,

Keith

oh it certainly is! The difference that I am gathering is that guitar community thinks of overdrive as a sound, but an engineer thinks of it as exceeding some design point in terms of voltages and/or currents.

I think that guitar terms have come from the labels the early amp designers put on the knobs to know what was being adjusted, then the folks that were playing associated it with a sound and that is where the connection came from.

so, back to the hiss on this amp - the one @Lefteris posted sounds pretty normal, but not significantly different in frequency content from @Avleen’s amp. I suspect Avleen’s is a lot louder in the room. This suggests gain is pinned to max somehow. Add the reverb oscillating, which is something you get when you have a lot of gain with some feedback, and it fits with the gain being stuck at max theory. I do think the amp is broken.

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@sequences @majik @Lefteris @jacksprat @jkahn
Hey guys, i would like to clear something up.
That reverb noise that you hear, maybe it had to do something with the power source because when i plugged into the main socket, the screech of reverb went away.
The hiss persists on both clean and gain channel.
What do you think now?
Still might be broken?

Dare I ask where you had it plugged in before?

I think you should do what @sequences Michael said. Unplug the guitar cable from the amp and see if the noise (hiss) persists.
If it does, it’s perhaps the amp.
If it doesn’t it comes from the pickups in which case shielding the guitar could help.

I did have a noise like this on an amp due to a very badly made cable (swapping the cable for one of higher quality solved it). Maybe try a different guitar cable?

I don’t follow what you mean by the “socket”.

Try rolling the ‘volume’ on the GUITAR all the way down and see what happens. Try removing the guitar cable and see what happens.

The amp gain is 6. If playing guitar is uncomfortably loud at that setting with guitar volume at max, then the hiss would be normal. If you turn the AMP volume down to a level you might have a conversation at, the hiss should be pretty low, but probably still something you can hear.

@Lefteris - does the above match your amp? I’m making some guesses here. :slight_smile:

If a wall outlet made noise, while another didn’t, check the bad wall outlet ground. Before you have a fire or something.

If it was an extension cable that added the sound just trash it.

Video response here https://youtu.be/Gwpyi7riZzc?si=v1vqze1ButHpD3yN

Just note that’s a guitar with humbuckers with the volume on the guitar all the way up.
The reason I’m saying “the very dirty channel” is because the amp has 4 voicings, clean/crunch and OD1/OD2 each different gain levels available. So to demonstrate I we t to the OD2 which is in war mode (but not as all out war as the metal zone that I’ve ended up using these days!:rofl:).

I’ll probaby take the video down soon though, I don’t like my voice :rofl:

Ps
Does this count as my 1st AVOYP?:joy::woozy_face:

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I think that should make a good comparison for @Avleen!

thanks for the help. :slight_smile:

I don’t hear much difference. If the “socket” is the wall outlet (probably different jargon used there?) then it sounds like the amp is ok, and the outlet is faulty like @Jamolay was suggesting. yes, that means I’d change my mind on the amp being broken. :slight_smile: