Gk 1001rb low volume

[6ornone]

Hey all, so I have a gk 1001rb mark ii. I love this amp and it’s worked phenomenally, until last week. I plugged everything in and it sounds like the 14db pad is on. Plugged a cable into the effects loop and got the proper amount of volume. So I took the cover off and everything looks good and connected. Deoxit the input jacks and still nothing. If I turn the input volume all the way up it gets good volume but that’s not right cause the woofer is maxed. Any ideas would be helpful

 

[BrentSimons]

Hey all, so I have a gk 1001rb mark ii. I love this amp and it’s worked phenomenally, until last week. I plugged everything in and it sounds like the 14db pad is on. Plugged a cable into the effects loop and got the proper amount of volume. So I took the cover off and everything looks good and connected. Deoxit the input jacks and still nothing. If I turn the input volume all the way up it gets good volume but that’s not right cause the woofer is maxed. Any ideas would be helpful

Hi
Any chance the “Boost” knob was turned down? Silly question I know.
Maybe check your speaker cables and instrument cables as well to rule those out.
Lots of great folks here on TB . I’m sure someone more knowledgeable than me will chime in!
Good luck !
Brent

 

[agedhorse]

We can be sure that it's not a "typical class D problem" at least...

 

[6ornone]

Hi
Any chance the “Boost” knob was turned down? Silly question I know.
Maybe check your speaker cables and instrument cables as well to rule those out.
Lots of great folks here on TB . I’m sure someone more knowledgeable than me will chime in!
Good luck !
Brent

Yup I play with the boost somewhat high so it wasn’t that. Tried a different cab and all the cables

 

[6ornone]

We can be sure that it's not a "typical class D problem" at least...

I was hoping you would respond since you have knowledge for days when it comes to amps

 

[agedhorse]

The only other thing to try is inserting a 1/4"plug into the effects return jack a few times, it's possible that the switch inside the jack isn't fully seated.

Other than that, it sounds like your amp needs to visit a qualified GK authorized service shop.

 

[6ornone]

I’ll try that in the morning. But that seems like the next logical step there’s a few around me. Time to pull out the old power amp/ pre amp pedal setup while it’s in the shop

 

[eniac]

Why not just keep running the amp the way you've already proven it works -- with a cable connecting the effects send to the effects return? My TH500 started exhibiting the same problem as your 1001 a couple years after I bought it (IIRC), so from that point onward I just ran it (and keep running it) with the effects loop bridged. Solid as a rock.

 

[groovaholic]

I plugged everything in and it sounds like the 14db pad is on. Plugged a cable into the effects loop and got the proper amount of volume

Sounds like you already knew to check the effects loop & that putting a jumper in the loop got the amp sounding normal again.

So I’d recommend spraying DeOxIt on a 1/4” plug* and inserting that plug into each effect jack multiple times - and give the plug a twist back and forth while it’s in.

Basically, all signs point to dirty effects loop jacks, and you just need to keep cleaning them.

*[DO NOT spray the DeOxIt directly into the amp - especially if it’s plugged in!

#1 the toroidal transformer is directly behind the effects jacks and if DeOxIt got into an energized transformer it would be bad, bad… poof.

#2 spraying directly into the amp would be WAY TOO MUCH DeOxIt]

 

[Ben Esparza]

Try cleaning those jacks with DRY .25 gun barrel brushes. You may also want to call GK in California and have them repair it and give the amp a once over.

 

[KevInDaBassment]

Ok I may be reading this wrong OP, but are you saying...

1) You plugged into the effects return and got proper volume, but when you plug into the normal input that's when you have issues

or

2) You put a cable connecting the effects send and return together, then the amp sounded fine. But if you just plug straight into the normal input without the effects loop jumpered, the volume is too low?


It's sounding like #1 at first blush for me, which just makes me think it could be any number of things in the preamp section. If you're going into the Effects Return ("Power Amp In" I think they call it?), I don't think you'll get anything but the Boost knob and Tweeter/Woofer volume knobs in your signal chain before hitting the power amp section of the amp. It should be bypassing the Pad, Input volume, shaping, and EQ sections.

Either way, I'd take it in for repair. A workhorse amp like that exhibiting issues is kind of concerning, but nothing lasts forever....well, except the Earth and Sky, I think?

 

[agedhorse]

Ok I may be reading this wrong OP, but are you saying...

1) You plugged into the effects return and got proper volume, but when you plug into the normal input that's when you have issues

or

2) You put a cable connecting the effects send and return together, then the amp sounded fine. But if you just plug straight into the normal input without the effects loop jumpered, the volume is too low?


It's sounding like #1 at first blush for me, which just makes me think it could be any number of things in the preamp section. If you're going into the Effects Return ("Power Amp In" I think they call it?), I don't think you'll get anything but the Boost knob and Tweeter/Woofer volume knobs in your signal chain before hitting the power amp section of the amp. It should be bypassing the Pad, Input volume, shaping, and EQ sections.

Either way, I'd take it in for repair. A workhorse amp like that exhibiting issues is kind of concerning, but nothing lasts forever....well, except the Earth and Sky, I think?

Correct conclusion imo.

 

[agedhorse]

Try cleaning those jacks with DRY .25 gun barrel brushes. You may also want to call GK in California and have them repair it and give the amp a once over.View attachment 7143694

This isn’t going to help, even if it was the internal normalling switch, a brush won’t get anywhere near it and may cause more damage.

 

[Ben Esparza]

This isn’t going to help, even if it was the internal normalling switch, a brunch won’t get anywhere near it and may cause more damage.

This is good information to know from a trusted source. Thanks, agedhorse.

 

[Thumpin6string]

I've had a few RB heads that did this, and it was the effects loop. Try a patch cable between the send and return jacks.

 

[6thplanet]

Just for visual reference, here's where the switching contacts are on an open and closed frame jacks. This is why inserting anything into the jack won't "clean" the switch.

 

[6ornone]

Just for visual reference, here's where the switching contacts are on an open and closed frame jacks. This is why inserting anything into the jack won't "clean" the switch.
View attachment 7143859
View attachment 7143860

So could I take the top cover off again and try and clean those technically it would that cause more harm

 

[agedhorse]

So could I take the top cover off again and try and clean those technically it would that cause more harm

Yes, if it’s not the cause now, it could become a new problem.

If a cable between the effects send and return jacks didn’t fix the issue, it’s NOT the switch inside the jack.