Horrible Static From Bogner Speaker Cab. Video Inclued

R

randomdude

New member
Hey guys, out of nowhere my Bogner 2x12 speaker cab with Celestian V 30's is giving off horrible static. Nothing has changed in my setup so I have no clue what it is. I am sure its the speakers and nothing to do with the Bogner Atma head, but i am in no way a tech guy. I thought it was my guitar pots or switches or something but it gives off static with or without the guitar.

Please help guys. I have plugged the rig into other outlets in the house and have the same issue. I have plugged straight into the head without my pedalboard and still the same thing. All that makes me think its the speakers for sure.

Hopefully my description and video is enough to help me diagnose. I do have a warranty still with the bogner but really don't wanna ship that speaker cab from chicago to california lol.


Heres the video so you guys can hear this horrendous static that is making me crazy lol
https://youtu.be/4-VtuG5B1Mc
 
I think it’s the amp head. Do you have another speaker cabinet to try? Or another amp to try through the cabinet?
 
psychodave":1nokkay2 said:
I think it’s the amp head. Do you have another speaker cabinet to try? Or another amp to try through the cabinet?
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unfortunately i don't lol, i wish i did. i was just telling my wife i need another one now so I'm not stranded from playing lol.

I'm still trying to diagnose this problem. I have eliminated my pedalboard completely and my foot switch for the amp too. still getting the static so it must be the amp. doesn't do it automatically though, takes a bit sometimes.
 
Clean the input, outputs, and all tube sockets w/Deoxit cleaner. Clean one component at a time, as Deoxit is quite expensive. Those enclosed Cliff jacks are notorious for caking-up with filth... muck! Replace one tube at a time with a known viable tube. Other things can be done, but do the above first. I had a boutique amp that did the sam thing. It was a gummed-up Cliff input socket.
 
Goat":1e6asrnm said:
Clean the input, outputs, and all tube sockets w/Deoxit cleaner. Clean one component at a time, as Deoxit is quite expensive. Those enclosed Cliff jacks are notorious for caking-up with filth... muck! Replace one tube at a time with a known viable tube. Other things can be done, but do the above first. I had a boutique amp that did the sam thing. It was a gummed-up Cliff input socket.
Click to expand...

thanks for the suggestions. i have narrowed it down somewhat. the cracking/static will happen without anything plugged in and just having the amp turned on.

i will say that the amp was serviced by bogner in CA last August. There was an effects loop issue which was a "Faulty high voltage transistor in loop circuit caused static noise". sent the amp to sweet water and they shipped it out to bogner from there.

i will say that before sweet water sent the amp out, they wanted to troubleshoot a bit and left the amp on for over 24hrs to see if they were hearing anything with the previous issue i was having. i wasnt to happy about that because i told them it was an effects loop issue and they didnt have anything plugged in there. they just had the amp on which i assume put undue use on my tubes? i hope its not a cause of that.

i would think that bogner would have noticed anything else wrong before they sent the amp back out though.
 
randomdude":7wiqweno said:
Goat":7wiqweno said:
Clean the input, outputs, and all tube sockets w/Deoxit cleaner. Clean one component at a time, as Deoxit is quite expensive. Those enclosed Cliff jacks are notorious for caking-up with filth... muck! Replace one tube at a time with a known viable tube. Other things can be done, but do the above first. I had a boutique amp that did the sam thing. It was a gummed-up Cliff input socket.
Click to expand...

thanks for the suggestions. i have narrowed it down somewhat. the cracking/static will happen without anything plugged in and just having the amp turned on.

i will say that the amp was serviced by bogner in CA last August. There was an effects loop issue which was a "Faulty high voltage transistor in loop circuit caused static noise". sent the amp to sweet water and they shipped it out to bogner from there.

i will say that before sweet water sent the amp out, they wanted to troubleshoot a bit and left the amp on for over 24hrs to see if they were hearing anything with the previous issue i was having. i wasnt to happy about that because i told them it was an effects loop issue and they didnt have anything plugged in there. they just had the amp on which i assume put undue use on my tubes? i hope its not a cause of that.

i would think that bogner would have noticed anything else wrong before they sent the amp back out though.
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The cord doesn't need to be plugged in for the input jack to cause a problem. I learned this the hard way... trust me on this. The phase inverter tube and/or tube socket can cause this issue as well.
 
so sweet water got back to me and suggested trying to troubleshoot if its a preamp issue and that i could swap those out myself. they sent me a link to their troubleshooting tubes video. not sure i really feel comfortable doing any of that though. I've never messed with amps. i am hoping they can locate a bogner certified repair tech near me in chicago. otherwise it looks like I'm gonna have to ship it out to sweet water so they can send it to bogner like they did last year.

i think this means I'm gonna have to start shopping for a back up amp lol.

i will keep you posted guys. i am gonna take the cover off the amp today and try and troubleshoot the tubes some. just not too comfortable or knowledgable in exactly what I'm looking for.
 
ok, update for anyone who is interested. just got off the phone with a sweetwater tech. he had me switch the first and last pre amp tubes around to see if that was the cause of anything. something he said about inputs coming into one tube and out the other, didnt really understand it. he wanted to check that though. static was still happening though, so he then had me take out the 3 pre amp tubes one by one. after taking out each preamp tube the static/crackling was still there.

at that point he said its not the pre amp tubes and that he is pretty confident that swapping out the 2 power tubes will be the solution.

just ordered the exact JJ el84 pair from guitar center, i had a gift card, so when it comes in i hope thats the solution. he did say the atma is a type A amp so swapping the power tubes out means it does not have to be biased.

cheers everyone and i will give you another update in a week when the tubes come in. fingers crossed.
 
BXCs99h.png
 
hey guys, thought i would give you the update. i just got in the new power tubes, same jj el84 matching set. played for about 30min with no issues. can't believe it, i thought i would have to have sent it in for service for sure. $39 for the matching set and problem solved.

thanks for the help guys.
 
randomdude":18bequs7 said:
hey guys, thought i would give you the update. i just got in the new power tubes, same jj el84 matching set. played for about 30min with no issues. can't believe it, i thought i would have to have sent it in for service for sure. $39 for the matching set and problem solved.

thanks for the help guys.
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Glad you caught the failing tubes before they went south. Power tube failure has been known to cause all kinds of problems from blown screen grid resistors to taking out the power transformer with them. Good catch!

Be sure to stay on top of your tube life and make sure the amplifier is biased correctly. Power tubes are not hot-swappable unless you get them replaced with a known current rating for the current bias setting.

Biasing should be done by an experienced technician BTW.

Cheers,
-Matt
 
glpg80":sluzbagf said:
randomdude":sluzbagf said:
hey guys, thought i would give you the update. i just got in the new power tubes, same jj el84 matching set. played for about 30min with no issues. can't believe it, i thought i would have to have sent it in for service for sure. $39 for the matching set and problem solved.

thanks for the help guys.
Click to expand...

Glad you caught the failing tubes before they went south. Power tube failure has been known to cause all kinds of problems from blown screen grid resistors to taking out the power transformer with them. Good catch!

Be sure to stay on top of your tube life and make sure the amplifier is biased correctly. Power tubes are not hot-swappable unless you get them replaced with a known current rating for the current bias setting.

Biasing should be done by an experienced technician BTW.

Cheers,
-Matt
Click to expand...

hey there, thanks for the tips. sweetwaters tech that walk me through some trouble shooting stated that my amp is a type A which he said doesn't have to be biased. do you agree with this. i guess i should have googled to make sure. i will now.
 
randomdude":3ctsnz7e said:
glpg80":3ctsnz7e said:
randomdude":3ctsnz7e said:
hey guys, thought i would give you the update. i just got in the new power tubes, same jj el84 matching set. played for about 30min with no issues. can't believe it, i thought i would have to have sent it in for service for sure. $39 for the matching set and problem solved.

thanks for the help guys.
Click to expand...

Glad you caught the failing tubes before they went south. Power tube failure has been known to cause all kinds of problems from blown screen grid resistors to taking out the power transformer with them. Good catch!

Be sure to stay on top of your tube life and make sure the amplifier is biased correctly. Power tubes are not hot-swappable unless you get them replaced with a known current rating for the current bias setting.

Biasing should be done by an experienced technician BTW.

Cheers,
-Matt
Click to expand...

hey there, thanks for the tips. sweetwaters tech that walk me through some trouble shooting stated that my amp is a type A which he said doesn't have to be biased. do you agree with this. i guess i should have googled to make sure. i will now.
Click to expand...

Class A means linear, but that doesn’t imply fixed bias which makes the cathode more positive than the grid, or grid bias which uses an adjustable negative voltage to make the grid more negative than the cathode. Two different biasing methods but both can be used for class A.

I would say traditionally grid bias is used more commonly in class AB amplifiers and cathode bias in class A, but I’m not familiar with your amplifier to know for sure. Just know the class isn’t as important as knowing the two biasing techniques which is why you’re dabbling in technician territory.
 
glpg80":p0mxz9zo said:
randomdude":p0mxz9zo said:
glpg80":p0mxz9zo said:
randomdude":p0mxz9zo said:
hey guys, thought i would give you the update. i just got in the new power tubes, same jj el84 matching set. played for about 30min with no issues. can't believe it, i thought i would have to have sent it in for service for sure. $39 for the matching set and problem solved.

thanks for the help guys.
Click to expand...

Glad you caught the failing tubes before they went south. Power tube failure has been known to cause all kinds of problems from blown screen grid resistors to taking out the power transformer with them. Good catch!

Be sure to stay on top of your tube life and make sure the amplifier is biased correctly. Power tubes are not hot-swappable unless you get them replaced with a known current rating for the current bias setting.

Biasing should be done by an experienced technician BTW.

Cheers,
-Matt
Click to expand...

hey there, thanks for the tips. sweetwaters tech that walk me through some trouble shooting stated that my amp is a type A which he said doesn't have to be biased. do you agree with this. i guess i should have googled to make sure. i will now.
Click to expand...

Class A means linear, but that doesn’t imply fixed bias which makes the cathode more positive than the grid, or grid bias which uses an adjustable negative voltage to make the grid more negative than the cathode. Two different biasing methods but both can be used for class A.

I would say traditionally grid bias is used more commonly in class AB amplifiers and cathode bias in class A, but I’m not familiar with your amplifier to know for sure. Just know the class isn’t as important as knowing the two biasing techniques which is why you’re dabbling in technician territory.
Click to expand...

wonderful info, thank you so much. i will look into it right now.
 
ok, just got off the phone with a bogner amp tech out in california. he stated that it absolutely needs to be biased and should not be played until its biased, or else I'm risking damage which will not be covered under warranty either.

i just sent an email to the sweetwater tech that told me the complete opposite so we shall see what his response is. i have never taken an amp in anywhere so i need to find a reputable one here in chicago.

bogners website has this amp listed as "EL84 class-A cathode biased power amp with EZ81 tube rectifier delivers 18 watts"
 
A class A cathode biased amplifier can still be biased and need biasing - you do so by changing out the cathode resistors. A grid biased amplifier you adjust a grid bias voltage. What bogner said is correct as just because you swapped tubes and it’s cathode biased doesn’t mean you shouldn’t bias it especially for class A.
 
glpg80":dosz6lom said:
A class A cathode biased amplifier can still be biased and need biasing - you do so by changing out the cathode resistors. A grid biased amplifier you adjust a grid bias voltage. What bogner said is correct as just because you swapped tubes and it’s cathode biased doesn’t mean you shouldn’t bias it especially for class A.
Click to expand...

can't thank you enough for your help. I'm really pissed at sweetwaters tech for not knowing that. just out of curiosity, about how much do you think a tech should be charging to re bias the amp for me? I'm in chicago so I'm sure its more than most places lol.
 
Yep no problem! Sorry you’re learning as you go, most tube amp stuff usually is these days, lots of misinformation out there. I’m an MSEE so I’m very familiar with them.

Most techs shouldn’t charge much, maybe $30-50 tops. They need to check the plate voltage installed to see the optimal point on the curve to bias. Next they will measure the voltage across the resistor, and use ohms law to see what their quiescent bias current is currently set at. If it needs adjustment then they will swap out the resistors and repeat the process to verify it’s good.
 
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