GK 700rb buzzes and distortion?

[milosinka1]

Hello! I bought brand new GK 700rb II amp head last week. I connected it to Ampeg SVT 410 HLF speaker and , even on the low volumes , such as 1, started to buzz and distort. I though it was up to speaker, so I connected it to Avatar 210 NEO and still have same problems. I experimented with different horn volumes and different settings on amp ,but same problem occured. Does anybody have suggestion,is it necessery to return the thing to seller , or something else? Thank you!

[jeffkew]

There may be a problem with the amp, but just make sure that you aren't overloading the input section. I recently bought the same amp and have found that there is a definite limit to how far you can turn up the "volume" knob before you start hearing unpleasant distorting, even with a passive bass. With my passive J, anything past 12noon on that knob will distort. If you have an active bass, I would assume you'd need to keep this knob even lower, maybe even use the input pad.

[Hopkins]

If its brand new go swap it out for another one. You probably just got one with a defect.

[BassPlayer3187]

I have owned and used a 700rb-II head for almost 5 years now. I use both active and passive basses through it and have never had this problem, even with the volume knob cranked up to about 3-4 oclock. It could be a loose wire or connection somewhere in the head. Since you have already said you tried a different cab, I would recommend trying a different bass and different cables. If neither of these changes make a difference I would def send it back to where you got it and make sure they fix it. The head should NEVER cause your tone to distort or buzz unless there is some sort of wiring issue or you are sending to much signal (either ohms or watts) to the cabinet. Go back and check the specs of the head and the cabinets and make sure they work together well. Also you can always call GK they have been very helpful for me every time I have had an issue with something!

[jeffkew]

Originally Posted by BassPlayer3187

I have owned and used a 700rb-II head for almost 5 years now. I use both active and passive basses through it and have never had this problem, even with the volume knob cranked up to about 3-4 oclock.

Just curious, when you say you crank it to 3-4 o'clock, are you talking about the knob labeled "volume" which is part of the input section? Or are you talking about the "woofer" knob in the output section? I keep my "woofer" knob maxed all the time, and I use the "volume" or input knob to adjust how loud I want to be. Again, if I set this input "volume" knob to 3-4 o'clock, I hear distortion with my Fender passive jazz. Hoping there isn't something wrong with my amp too!

[jeffkew]

Here is a discussion about the volume/woofer knob confusion:

GK700RB: When to use Volume/Woofer

[milosinka1]

thank you very much guys! I am pretty sure i'll swap the amp for another one!

[FretlessMainly]

There has been a great deal of discussion on this, but there always seems to be some confusion when you read all of the responses together. I've had a 700RB-II for five years, and here's what I've learned:

First of all, there are effectively four knobs that affect volume:

1: In the Input/Pre-amp section there's a knob labelled Volume. One would think that this would essentially be a master volume because of its labelling, but it actually seems to behave more like a channel volume in that if you turn it up too high, you get overdrive, but not good overdrive.

2, 3 and 4: In the Bi-Amp section, you have three knobs that control volume:

a) Boost
b) Tweeter
c) Woofer

Boost is where you get your GK growl, and it is somewhat subtle compared to say, Ampeg overdrive.

Tweeter is pretty self-explanatory; you can rotate through the full range of tweeter volume with no distortion (assuming you use the speakon cable for bi-amp mode, anyway).

Woofer also allows pretty much a full range of low to high with little or no distortion.

So, here's what I do:

Volume: I start with this very low, around 8 o'clock at most.
Boost: I crank this up to 3-3:30 and leave it there untouched any further.
Tweeter: Do whatever you like; it shouldn't affect tone at all, just tweeter contribution to the mix. I like it at about 10-11:00.
Woofer: Depending on where I'm playing (home, rehearsal studio or club), I'll start this on about 9:00 and increase this to about 3:00 before I'll even touch the "Volume" knob. So, in home or other low-moderate situations, this is my main volume knob. In a club, I'll also add some of the Volume knob after getting the Woofer up to 3:00 or so.

What helps to demonstrate how these knobs really work is having my rack-mounted compressor hooked up. I have an Alesis 3630 and raising the Boost, Tweeter ot Woofer knobs does very little to increase the compression (the Alesis has a nice long set of leds for input/output and compression). As soon as I even touch the Volume knob, the compression increases significantly. Thus, volume really boosts your pre-amp signal, which will lead to distortion of the bad kind if you kick it too high.

This line of GKs are really meant to be run clean but with some grit/growl. If you want Ampeg overdrive, get an Ampeg.

Of course there's one other thing I didn't mention: if you have an active bass, did you pad your input with the pad button?

[ljazz]

FretlessMainly describes it pretty good.......

But I'll add just a couple of things...... another common misconception is that the volume knob is "input gain." It is in fact "preamp gain", so cranking on that so thinking that you're good until the clip light comes on would be a mistake, and creates a lot of unpleasant clipping and distortion. Use the input pad, your bass vol knob, or any effects to bring up/down your input gain. I try to keep the "vol" knob no higher than 10:00-11:00. Much higher, and it starts to get a bit ugly. I start with my master/woofer at noon, boost at 3:00, and use the "vol" knob to control my vol up until I'm at 10-11:00. If I need more volume, then I'll start bringing up the master/woofer, while backing off a touch on the boost. Remember, there is more to the GK Growl than just the boost knob..... it has a lot to do with how the power section operates..... keeping the master/woofer up, along with higher boost settings will maximize the growl.

I'm willing to bet that you set the vol knob too high, thinking it was input gain...... common mistake with GK heads. GK would help themselves, and their new customers, a bunch if they would relabel that section of the head.

[milosinka1]

Again, thank you guys very much! But ( what I missed to mention) ,I knew all of these, I usually keep Volume just a little bit (8 o'clock), boost on 12 o'clock and woofer at 12 o'clock ( I don't tweek the tweeter , cause my speakers are not bi-ampable), and still have buzzes and cliping. Yes , I play ACTIVE stingray, but I avoid to press input Pad, because it gives me sterile sound, so I still pretty much think about returning the amp head and switching for another.Anyways, I appreciate your help very much, this website is very good for exchanging experience and informations.Thank you!

[FretlessMainly]

Originally Posted by milosinka1

Yes , I play ACTIVE stingray, but I avoid to press input Pad, because it gives me sterile sound, so I still pretty much think about returning the amp head and switching for another.

If you return the amp for a replacement, you'll have the exact same problem (if they even replace it, because it's likely there's nothing wrong with it, so all you'll be doing is paying $$ to ship 25 lbs of perfectly good electronics around the country). You have to either pad your input or reduce the bass setting on your bass (at the least).

When you pad your input, use the boost and woofer knobs to bring your levels back up to 3 or 4 o'clock and then use the volume. That's just the way active basses work in this kind of set-up.

[Rebmo]

I have 2 700rbIIs that I bought used here on TB and both are great. I guess I got lucky, but so far I can get the exact sound I'm after for once. I wish they had the boost footswitch like the 800rb I have, but other than that, awesome amp. I run clean punchy G&L L1K, P-bass, and Stingray sound in a Alt Pop Rock cover band. They can growl, but I use very little boost overdrive. Typically I run through a Hartke Hydrive 115 and 410. Super punch and lots of air moving at the right time. Clean cut through tone and simple quick EQ although I run basically flat, but some rooms need a few tweaks on the low mid, and low frequecy.

Great head

[lbwdog]

Have you checked the bass battery and all input and speaker cables?

[joshmmorrison]

Originally Posted by FretlessMainly

There has been a great deal of discussion on this, but there always seems to be some confusion when you read all of the responses together. I've had a 700RB-II for five years, and here's what I've learned:

First of all, there are effectively four knobs that affect volume:

1: In the Input/Pre-amp section there's a knob labelled Volume. One would think that this would essentially be a master volume because of its labelling, but it actually seems to behave more like a channel volume in that if you turn it up too high, you get overdrive, but not good overdrive.

2, 3 and 4: In the Bi-Amp section, you have three knobs that control volume:

a) Boost
b) Tweeter
c) Woofer

Boost is where you get your GK growl, and it is somewhat subtle compared to say, Ampeg overdrive.

Tweeter is pretty self-explanatory; you can rotate through the full range of tweeter volume with no distortion (assuming you use the speakon cable for bi-amp mode, anyway).

Woofer also allows pretty much a full range of low to high with little or no distortion.

So, here's what I do:

Volume: I start with this very low, around 8 o'clock at most.
Boost: I crank this up to 3-3:30 and leave it there untouched any further.
Tweeter: Do whatever you like; it shouldn't affect tone at all, just tweeter contribution to the mix. I like it at about 10-11:00.
Woofer: Depending on where I'm playing (home, rehearsal studio or club), I'll start this on about 9:00 and increase this to about 3:00 before I'll even touch the "Volume" knob. So, in home or other low-moderate situations, this is my main volume knob. In a club, I'll also add some of the Volume knob after getting the Woofer up to 3:00 or so.

Ridiculously helpful. I was wondering why it didn't seem to have the volume that i anticipated, and when i cranked it up it sounded like kuh-rap. This does wonders. Thank you very much!