Quick question - GK 1001RB-II - Pop when powered on?

lowend range · #1 08-10-2010, 06:02 PM

I purchased a used but mint condition GK 1001-RBII which is plugged into one of my Mesa 4x10 roadready cabinets (old style)

Is it normal to hear a loud "thud" or pop when the red light turns blue? I know a lot of amps specifically leave out whatever that part of the circuit is called so it pops, (SWR comes to mind) but I never read anywhere about GK amps doing it....

Any help or answers? (I tried it with the mute button on as well, and it still does it)

Thanks.

Ozzey · #2 08-10-2010, 08:48 PM

I don't believe my 1001RB-II has popped or anything. I turn it on, red light, then it turns blue and you hear the bass signal loud and clear. So long as it doesn't take away from the overall functionality, I think you're okay. If it gets any worse though, you may want to have it checked.

Marton · #3 08-10-2010, 08:53 PM

Mute the amp when it warms up ?

Maybe my 700RB-II do it, I don't know, it's always muted when I power it up.

johnk_10 · #4 08-10-2010, 09:25 PM

i just checked mine and my 1001RBII makes the tiniest (almost completely inaudible) thump when the light switches from red to blue.

lowend range · #5 08-10-2010, 10:36 PM

Quote:

Originally Posted by Marton

Mute the amp when it warms up ?

Maybe my 700RB-II do it, I don't know, it's always muted when I power it up.

I tried it muted as well, it still makes a very audible, kind of loud thump in my speakers.

Quote:

Originally Posted by johnk_10

i just checked mine and my 1001RBII makes the tiniest (almost completely inaudible) thump when the light switches from red to blue.

Hmmm.... I think I may have to have mine looked at. Mine is much louder.

Slowgypsy · #6 08-10-2010, 10:51 PM

I've got the 700RB-II. I always start it up with the mute button engaged, and it does make a slight but noticeable dull pop type sound when the red power light turns blue. I bought this amp new a couple of years ago, it gets turned on daily, it's been gigged frequently, and this sound has been there since day one. Never bothered me, hasn't gotten any worse, and I believe it's a normal starting up type of thing.

If you have any doubts about your amp, just give GK a call. You'll more than likely get connected to a real person within moments and get the info you need.

Lutuh · #7 08-10-2010, 11:08 PM

No pop on my 700RB-II. I power it up unmuted.

rag · #8 08-11-2010, 06:27 AM

Quote:

Originally Posted by lowend range

I purchased a used but mint condition GK 1001-RBII which is plugged into one of my Mesa 4x10 roadready cabinets (old style)

Is it normal to hear a loud "thud" or pop when the red light turns blue? I know a lot of amps specifically leave out whatever that part of the circuit is called so it pops, (SWR comes to mind) but I never read anywhere about GK amps doing it....

Any help or answers? (I tried it with the mute button on as well, and it still does it)

Thanks.

Contact brian@gallien.com, this is an easy fix.
Bob

**mikeddd** · #9 08-11-2010, 06:42 AM

Quote:

Originally Posted by rag

Contact brian@gallien.com, this is an easy fix.
Bob

Now THAT'S customer service!

skb5string · #10 08-11-2010, 06:46 AM

Quote:

Originally Posted by mikeddd

Now THAT'S customer service!

Wow! No kidding! +++++1 to GK!!

lowend range · #11 08-11-2010, 07:18 AM

Quote:

Originally Posted by rag

Contact brian@gallien.com, this is an easy fix.
Bob

Thanks!

Santoso · #12 10-26-2010, 07:52 AM

What was the quick fix? I am having the exact same issue.
KT

AmpFixerGuy · #13 Today, 12:01 PM

Hey guys,

I have a 1001RB-ii that makes a pop at turn on (right when the red LED turns blue).

If anyone knows of a the fix for this isse, you would really make my day here by sharing the solution.

Thanks.

BassmanPaul · #14 Today, 12:33 PM

I think you may find that the amps output has a small DC component to it and thus the pop. it should be a simple fix to null out the offset to zero.

**B-string** · #15 Today, 12:45 PM

The schematic has the bias procedure right on it. RAG is awesome that way, I wish ALL manufacturers did that. With some it is like pulling teeth with tweezers trying to get setup info.

AmpFixerGuy · #16 Today, 03:48 PM

Yes, the schematics for this amp are well done and the amp is well made. I have set the bias as per the instructions and the problem remains.

Here is an oscilloscope waveform of the amplifier's output to ground. The ~300ms, +50Vpulse happens the moment the red LED goes blue. As you can imagine, the speaker jumps.

You can see that just before the pulse the output it slightly negative. After the pulse settles the DC level on the ouput is zero. The amp then works perfectly and can put out 400W into 4ohms no problem.