Loud thump when turning amp on

Tommy Boswell · Post by **Tommy Boswell** » 4 May 2017 9:08 am

How many of you Peavey 400 amp users hear a loud thump when you switch on the power? Does that mean there's something wrong with the amp? And is it easy to fix?

My amp sounds great otherwise, just have to wonder if it will damage the speaker.

Rick Johnson · Post by **Rick Johnson** » 4 May 2017 9:12 am

Both my NV400 and Session 500 do this too.
Its just a surge of sorts energizing the speaker.
They did when brand new too.
Try turning the volume down before you turn it on.

Rick

www.rickjohnsoncabinets.com

Tommy Boswell · Post by **Tommy Boswell** » 4 May 2017 9:23 am

Thanks Rick. It's my first 400, a Reno loaded into a very fine Rick Johnson cabinet...looks as good as it sounds!

Tucker Jackson · Post by **Tucker Jackson** » 4 May 2017 9:27 am

There was a thread on the forum many years ago about this. The upshot was that lots (most?) NV400s make a loud pop sound when powered on. It's considered a normal quirk of the amp and it apparently doesn't cause any damage.

My 400 does it... but I do keep volume and gain knobs set to zero before hitting that power button on.

Lane Gray · Post by **Lane Gray** » 4 May 2017 9:47 am

It's called the Peavey Pop.
Unless your speakers are weakened, it's harmless.

Brad Sarno · Post by **Brad Sarno** » 4 May 2017 6:47 pm

Agreed, normal and harmless. It's a simple amp, and that's a good thing. It has no mute or timing circuit to deal with the power-on pop. Just live with it. Totally normal for that amp.

B

Stu Schulman · Post by **Stu Schulman** » 4 May 2017 11:38 pm

Both of my LTD's do this!

Paul Sutherland · Post by **Paul Sutherland** » 4 May 2017 11:41 pm

It's kind of fun to turn on or off a Peavey when your amp is mic'd into a large PA. The sound engineers really freak out. I just try to look innocent.

John Booth · Post by **John Booth** » 5 May 2017 4:47 am

Yep, just the ole "Peavey Pop"
They all do it
JB

Richard Sinkler · Post by **Richard Sinkler** » 5 May 2017 8:24 am

Paul Sutherland wrote:It's kind of fun to turn on or off a Peavey when your amp is mic'd into a large PA. The sound engineers really freak out. I just try to look innocent.

The reverb in my NV400 doesn't work, so I use a Hall of Fame reverb pedal. I was running it through my front panel effects loop, but it has developed a high frequency hum. I've been using it between the preamp out and power amp in jacks. If I don't turn both gain controls to zero, it sounds like a nuclear explosion when I turn at on. It will take down an airliner at 20,000 feet.

Rich Upright · Post by **Rich Upright** » 9 May 2017 5:59 pm

Every PV I've ever owned did this, & I owned a LOT of PV amps. My current Renown 400 1-15" does it.

Mike Brown · Post by **Mike Brown** » 10 May 2017 6:32 am

Solid state amp, instantaneous power.

John Dowden · Post by **John Dowden** » 10 May 2017 3:37 pm

Every tube amp I've had does this as well to some degree.

Peter Harris · Post by **Peter Harris** » 11 May 2017 4:20 am

I also get a loud thump every time I turn the amp on...
....but only when my wife is trying to use the phone...

Will Cowell · Post by **Will Cowell** » 12 May 2017 6:28 am

Hmmm, I though *everyone* turned their amp gain down to zero before switch-on or switch-off, or before connecting/disconnecting instruments or other equipment.

It's a valuable discipline, and avoids the risk of inadvertent damage through surges or transients.

Derrick Unger · Post by **Derrick Unger** » 12 May 2017 12:40 pm

My Nashville 400 makes 3 to 4 loud pops within about the first 20-30 seconds after I turn it on..makes the little clip light come on..doesn't do it again at all even if its on for hours..I just ignore it..doesn't seem to effect it..scares the s**t out of people not expecting it!!!

Mike Brown · Post by **Mike Brown** » 12 May 2017 1:06 pm

Derrick, that is a problem and our techs can resolve it for you. I recommend that you send the chassis to the factory for repair.

Ken Fox · Post by **Ken Fox** » 13 May 2017 6:57 am

That may be related to a dirty pot, namely the mid shift pot. Does it make a popping or other strange sound when turned? If so clean it. It can fire of a sound as loud as a 38 caliber pistol when it is dirty!

Mike Wheeler · Post by **Mike Wheeler** » 13 May 2017 7:51 am

I like the new avatar, Ken. And I agree about the mid shift pot needing cleaning.

Ken Fox · Post by **Ken Fox** » 13 May 2017 10:56 am

Thanks, Mike. That is my wife, Linda.

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