Amp experts, am I out of luck? (just got amp back from repair guy)

[El-Bob]

Well, I bought a used Gallien Krueger 400RB IV head maybe a month ago. I also bought a cab with it (yorkville 4x10, which still works great), and it tested fine. The previous owner had just brought the head back from the same repair shop which I would later take it to. The repair guy felt that he had fixed the problem, and the amp seemed fine for the entire first band practice I used it for. Super loud and amazing tone. The next band practice, it started to make some crackling sounds after a while, almost like someone was adjusting a scratchy volume pot. This sound would continue even when the amp was muted. By the end of the practice, there was a high pitched squealing sound reminiscent of a dial-up internet connection.

So, I took the amp to the repair guy, and he looked at it for about two weeks. Said he went over it again and again, checking everything. He seemed determined to figure it out, but in the end said he just couldn't find a problem. Everything looked good. He feels like he may have isolated it to something in the power amp, but that's all he knows. The description he listed on the receipt when I picked up the amp was "After about 10 minutes, it sounds staticky and then it sounds like a dial up modem".

So, is this a lost cause? I'm a university student, and I can't really afford another head right now, or even an abnormally expensive repair. I can live without the amp, as I am borrowing a friend's SVT-3 pro head, but it's just not the same. I fear that all hope is lost.

[Muttleybass]

Did you get the cab checked? I had a similar issue and it was the speakers.

[El-Bob]

Originally Posted by Muttleybass

Did you get the cab checked? I had a similar issue and it was the speakers.

The cab is perfect, I use it every week with an Ampeg head. All the cables are fine, the bass is fine. It's the head. The head also has the same problem through any speakers. Like I said, the repair guy thinks he isolated it to the power amp. He was able to reproduce the sound through other speakers. Or maybe the better statement is that he was unable to not reproduce it.

[mjac28]

Find another repair guy unless he's the only one in town have you contacted Gallien Krueger? if the first owner was having the same problem it could be a lemon.

[El-Bob]

I haven't contacted Gallien Krueger, I assume there's no warranty or anything so I didn't think there would be much point. Perhaps I should fire them an e-mail.

[bgavin]

I have a long career in computer service, and can state there are good techs, bad ones, and a few exceptional ones.
50% of all medical doctors graduate in the bottom half of their class (but are still called "doctor").

Find another tech.

Usually there is somebody who has a special reputation in the music community.
Here in Sacramento the name "Dr. Rock" is one of the go-to amp techs.
He worked on my daughter's Marshall JCM800 and fixed it up a treat.

[BassmanPaul]

In your position I'd think about returning the amp to GK. It'll cost you a bit for shipping but the amp will work as new when you get it back.

[B String]

GK heads are know for having issues with their effect loops. I'd bet your guy didn't clean or work the effect loop jacks a little. Its worth a try.
I know it seems like an overly simple thing, but try working a guitar cable end in and out of the effect loop jacks a few times. Spraying the input jacks with a good electronics cleaner first is even better.
This is quick and easy and might save you time and money.

If this doesn't work, find another tech.

[Mykk]

My first stab in the dark was going to point at the effects loop too... specifically the power amp input since it was making noise while the amp was in mute.

[OneWayPunk]

Dirty effects loops jacks was going to be my suggestion as well, all your symptoms point to it.
Sounds like you need a new tech.

[mjac28]

I really feel sorry for you I had similar issues with a Warwick head replaced caps, sections of the preamp etc still sounded terrible ended up dumping it to Guitar Center it stayed there almost a year

[DWBass]

Contact TB member rag (Robert A. Gallien). He should be able to take care of you.

[dincz]

Originally Posted by OneWayPunk

Dirty effects loops jacks was going to be my suggestion as well, all your symptoms point to it

Except that even a mediocre tech would have worked that one out.

[bolophonic]

Insert a short cable between the two jacks on the effects loop and see if it doesn't improve.

[El-Bob]

I will try the cable in the jacks at practice tonight. If it's no good, I will message Mr. Gallien. Thanks a ton for all of your suggestions guys!

Edit: If the short cable in the effects loop fixes the issue, can I just leave it in there and keep using the amp until i get some sort of contact cleaner?

[Crater]

Originally Posted by El-Bob

Edit: If the short cable in the effects loop fixes the issue, can I just leave it in there and keep using the amp until i get some sort of contact cleaner?

You can leave it in 'til the second coming of Jesus if you want to. It does not harm the amp in any way. Good luck.

[bolophonic]

Originally Posted by Crater

You can leave it in 'til the second coming of Jesus if you want to. It does not harm the amp in any way. Good luck.

There are at least 5 guys here in town (myself included) with patch cords permanently installed in the effects loop of their GK's.

[El-Bob]

Well, I just got back from a 2 hour practice with the cord in the effects loop. It crackled a little after it was on for a while, so I pulled the cord out of the jack, put it back in and twisted it around gently a little. It seemed fine for the rest of the practice after that... I'm still a little apprehensive, but I'm hoping this is the key. Gonna get some contact cleaner soon, and I'll use it for our next practice on Monday and our set Tuesday if it continues to perform. Thanks again for the advice guys.

[soulman969]

Originally Posted by DWBass

Contact TB member rag (Robert A. Gallien). He should be able to take care of you.

I think this is a great idea. The man who designed them should have an idea of where that problem is coming from.

My next step would be to find a new tech. I've yet to meet on worth his salt who couldn't find a problem in an amp. He simply didn't explore far enough and gave up.

Sorry you're not in Denver. Here I'd know just who to send you to.

[walterw]

the "dodgy effects loop" thing happens with lots of amps, especially if that loop never gets used.