Bass Amp / Cabinet troubles

[traindmunkie]

Hello Everyone!

I'm a newcomer (this is my first thread) but I am a longtime bassist, so please, please, be patient with me. I could not find an existing thread for my problems, so if there is one (and there probably is) I apologize sincerely!

Here is my current issue:

In August, I purchased a Gallien Krueger NEO410 cabinet rated for 800 watts @ 8 Ohms. I have been using it in conjunction with an SWR Workingman 8004 T/O/P amp, rated for 450 watts @ 8 ohms (and 750 watts @ 4 ohms). At the time I thought it was rated for 750 watts @ 8 ohms, but I was wrong.

Note that all of my bass guitars have active electronics (1 - 2010 Schecter Stiletto Studio Elite 5 String; 2 - 2007 Palatino Electric Upright 4-String; 3 - 1989 Kramer Ferrington Acoustic / Electric 4 string; 4 - 1998 Ibanez ATK 300am 4-string), and I replace the batteries frequently.

The cabinet sounded great in the store (with an Ampeg Amp), but when I brought it home I instantly noticed a loud scratchy sound coming from the cabinet. It subsided for a while; however, in recent weeks, the problem has only gotten worse. I noticed that the cabinet is extremely sensitive to even the slightest vibrations (if you step firmly near the casters, without an instrument plugged in, it makes loud awful distorted sounds), and god forbid I slap my strings. I am using a speak-on connection to interface the two currently, but I experience the same problem with a 1/4" connection.

The amp itself sounds great in recording situations. I also experimented with my basses to determine if I was experiencing standing waves issues, as the problems seem to be worse as I play certain notes or frequencies. I have also tried moving the cabinet and amp around from room to room to see if in fact I am experiencing an issue with my small apartment, but to no avail.

Also note that I have note cranked this amp very high, and have not gigged out with it yet. I never push the volume or gain past the halfway mark on my rigs.

I'm starting to think one of four things:

1 - My amp is underpowered and is causing damage to my speakers. (If this is the case, should I consider purchasing a power-amp to boost the wattage delivered to the cabinet?)

2 - I live in a 103 year old building with outdated electrical, and am unsure if my amp / cabinet is receiving enough power from the electrical outlets.

3 - If these are standing waves perhaps I need to fill my cabinet with acoustical insulation.

4 - I have a blown speaker or a bad crossover.

If anyone thinks they may be able to shed some light on my situation it would be very much appreciated. I have attempted to contact Gallien Krueger via email, and six weeks later have yet to receive a response. I am also BROKE, trying to make it through my last month of college, and was hoping there would be some sort of cost-effective remedy for my solution. The rig is currently out of commission as to avoid any potential damage, and if I can't solve the issue, I plan to take it into my tech (when I have money set aside) to help me trouble-shoot.

I just thought I'd try here first, as I known that all of you are PROS.

Again, any advice or insight would be greatly appreciated!

Thank you ever so much!

-Brendan from Denver

P.S. Really, thank you so much!

[craig.p]

You're saying you can trigger the nasty sound by simply walking on the floor? That tells me there's something loose in the head. If you can maintain proper airflow doing it, put the head on a pillow or foam or similar, and see if things improve. I.e. isolate the head from all vibrations. And we'll go from there...

[anderbass]

Good advice^

How about taking your amp and cab to a music store and trying out a different amp with your cab, and then a different cab with your amp. It shouldn't take long to confirm if the problems with your cab or amp. (just tell-em you can only afford to buy an amp OR a cab, and wanna try out some different combinations.)

[traindmunkie]

Hi Craig!

First of all allow me to thank you for going out of your way to try and resolve my issue.

I went ahead and placed my head on top of a large pillow and placed it on a table some twelve feet away from the cabinet. I then proceeded to step firmly near the base of cabinet to test out our theory, and I am still hearing a distorted scratchy sound coming from the cabinet with each step.

What do you propose I should try next? I'm open to suggestions

-Brendan from Denver

[AwkwardLoudness]

Originally Posted by traindmunkie

The cabinet sounded great in the store (with an Ampeg Amp), but when I brought it home I instantly noticed a loud scratchy sound coming from the cabinet. It subsided for a while; however, in recent weeks, the problem has only gotten worse. I noticed that the cabinet is extremely sensitive to even the slightest vibrations (if you step firmly near the casters, without an instrument plugged in, it makes loud awful distorted sounds), and god forbid I slap my strings. I am using a speak-on connection to interface the two currently, but I experience the same problem with a 1/4" connection.

This only happens when your amp is plugged into the cab and turned on, right? There's not a trapped rodent in there, right? Have you tried the cab with different amp heads?

My first thought is that it's a bad solder joint in the amp. Another possibility is that you're getting radio interference.

Originally Posted by traindmunkie

I'm starting to think one of four things:

1 - My amp is underpowered and is causing damage to my speakers. (If this is the case, should I consider purchasing a power-amp to boost the wattage delivered to the cabinet?)

It's not possible to damage speakers by underpowering them. Why does this myth persist?

Originally Posted by traindmunkie

2 - I live in a 103 year old building with outdated electrical, and am unsure if my amp / cabinet is receiving enough power from the electrical outlets.

You could get an outlet tester to check. I don't think dirty voltage this would cause scratchy noises though unless maybe you had capacitors or transistors that were about to blow. Does the problem only happen in that building?

Originally Posted by traindmunkie

3 - If these are standing waves perhaps I need to fill my cabinet with acoustical insulation.

Insulation in a cabinet reduces standings waves, but those are not the source of 'scratchy' noises.

Originally Posted by traindmunkie

4 - I have a blown speaker or a bad crossover.

These are not the type of problems that would be intermittent. A blown speaker sounds like crap but not scratchy.

[craig.p]

Except... it sounds like the cab was running 100% with the Ampeg head he tried it with at the store. My guess is that there's something loose or corroded in the head and he'll be able to get by with some physical isolation of the head until he stops being broke, LOL. By the way, TM, if you don't want to set the amp directly on a pillow, you can put a board between the amp's bottom and the pillow, to maintain proper cooling. Just make sure all the amp's feet are on the board so you have that air space.

[craig.p]

Still happening, huh? Hm. Maybe flaky speaker cable? Try another, or open yours up to see how the ends look. Also check the cable length itself for creases or punctures, as in something heavy having rolled over it, cat having chewed on it, etc.

[craig.p]

Never mind that last suggestion. I see you've already tried another cable. My apologies.

Guess the next step is to pull the back plate on the cab, and see if something's some loose, or maybe a cold solder joint on one of the connectors or crossover (if the cab has a crossover).

[mrkreuzschlitz]

Cold solders can do nasty, nasty things.

[craig.p]

Yeah, Mr. K, wasn't there a recent post by someone having a similar cab problem and it turned out to be a cold solder joint either on the crossover board or at a speaker jack? I seem to recall the guy saying it was tough to spot/isolate and he'd missed it first time in. It was in the last couple of months or so.

[bombpop14]

Could be as simple as a bad cable...If not then the head.
I doubt it's the cab.

[traindmunkie]

Hello Anderbass!

Thank you for your advice! That seems to be a good way of getting right down to the issue. If I get time this weekend, I'll definitely run my amp and cab over to my local music store and see if they won't help me pinpoint my problem.

Again, your assistance is greatly appreciated!

-Brendan from Denver

[3k Mylz]

You have either a severe dirty power issue (Not likely, but I would recommend a power conditioner if you really want to have this head for a long time -dirty power sucks) or bad connections inside the amp head, obviously independent or after the signal passes from the DI. Many suggestions here are good ones-first take the head to GC or another shop and give it a go with another cab in a conditioned environment.

Any awkward humming when nothing is connected by the cab? - If so, lean towards a power issue. If not, you have a gremlin in the head or the main cab connection.

[traindmunkie]

Hello Awkward Loudness!

In what must've taken you two minutes you answered two months worth of turmoil! All four of those questions have been plaguing me day-in-day-out. I've spoken with many of my friends, as well as trusted technicians, and have gotten many conflicting answers. You seem to be a walking wealth of information, and you can plan on me shooting more questions your way in the future.

As for my particular issue, I am still experiencing it. However, as it has recently been brought to my attention, I may be having troubles with a cold-solder joint (with which i have no knowledge), so if you can shed any additional light on that subject for me I would once again be very thankful!

Thanks a million!

-Brendan from Denver

[traindmunkie]

Hey Craig!

Could you explain exactly what you mean by a cold-solder joint? That's new vocab to me..

Thanks a million!

-Brendan from Denver

[KramerBassFan]

Originally Posted by 3k Mylz

You have either a severe dirty power issue (Not likely, but I would recommend a power conditioner if you really want to have this head for a long time -dirty power sucks) or bad connections inside the amp head, obviously independent or after the signal passes from the DI. Many suggestions here are good ones-first take the head to GC or another shop and give it a go with another cab in a conditioned environment.

Any awkward humming when nothing is connected by the cab? - If so, lean towards a power issue. If not, you have a gremlin in the head or the main cab connection.

Do tell me - what is "dirty" power?

[traindmunkie]

You guys are like bass superhero's mixed with geniuses!

Thank you so far for all of your awesome advice!

I will update you with every step of the way until I resolve the issue, and hopefully it will help answer other's questions as well!

-Brendan from Denver

[Rockmusician]

Not sure what the problem is. I have always had great luck with GK.

[AwkwardLoudness]

Originally Posted by traindmunkie

Hello Awkward Loudness!

In what must've taken you two minutes you answered two months worth of turmoil! All four of those questions have been plaguing me day-in-day-out. I've spoken with many of my friends, as well as trusted technicians, and have gotten many conflicting answers. You seem to be a walking wealth of information, and you can plan on me shooting more questions your way in the future.

Thank you, but I don't claim to be an expert. I've restored and repaired some old tube amps, though it's not something I do often. Heck, I don't even know that a loose/bad/cold solder joint is the problem. It's my best guess based upon your description.

Originally Posted by traindmunkie

Hey Craig!

Could you explain exactly what you mean by a cold-solder joint? That's new vocab to me..

Thanks a million!

I'm not craig, but I'll give my answer. A solder joint is where liquid metal (lead and tin typically) is used to attached components to wires, motherboard, tagboard, etc. It's sort of like a weld but at lower temperature.

A cold solder joint is one that was not bonded well to one or both of the base metals to begin with so the joint separates easily usually due to mechanical vibrations from moving the amp around. The joining base metals need to be hot enough during soldering to enable good bonding...hence the name 'cold solder joint'. Even a good solder joint can come loose with enough force.

[waveman]

Originally Posted by KramerBassFan

Do tell me - what is "dirty" power?

Not very well grounded.