Changed tubes...now a big problem-FIXED.

Scotland · March 18th, 2006, 06:06 AM

I replaced all my pre amp and power tubes with J.J's. It then started buzzing very loudly even with nothing plugged in. I took them all out and put the old ones in again (also J.J's) but it's still buzzing just the same.
I'm stumped here, what could have done this ?
It was very very quiet before I did this now it's unuseable

Scott S · March 18th, 2006, 06:35 AM

Is it possible some of the tube contacts have gotten loose or dirty? I'm kind of grasping, but it might be worth a check...

Mitch Roberts · March 18th, 2006, 08:55 AM

Does your amp have reverb? If so, check your reverb cables. If one develops a short it can buzz like crazy. Maybe you bumped them around when you changed the tubes.

Scotland · March 18th, 2006, 09:20 AM

Pulled the reverb cables, still the same. Cleaned all the tube contacts and tightened them, still the same.
This is strange. I bet it's something real simple.

Long_Ghost · March 18th, 2006, 12:10 PM

I am by no means an expert in such matters, but had a similar problem, and the solution appeared in the referenced article.
Hoping this is of some help.

LG

http://groups.google.com/group/alt.g...f888287686a183

Wally · March 18th, 2006, 12:39 PM

Scotland, you need to do some basic research by pulling tubes to localize the problem. Start with V1..first on the right looking at the back of the amp. With the amp off, pull V1. Warm the amp up and bring it online. If the noise is no longer there, you have localized the problem. If the noise is still present, turn the amp off and reinsert V1. Amp off...repeat with V2 and so on. At some point I think the noise will disappear. This won't tell you exactly what is wrong, but it will lead to some idea of where the problem is. I am thinking that a tube socket has a problem....bad connection, crack, or maybe some dirt got in while you were changing tubes. Do you have any cleaner to spray in those sockets?

Scotland · March 18th, 2006, 02:42 PM

Quote:

Originally Posted by Wally

Scotland, you need to do some basic research by pulling tubes to localize the problem. Start with V1..first on the right looking at the back of the amp. With the amp off, pull V1. Warm the amp up and bring it online. If the noise is no longer there, you have localized the problem. If the noise is still present, turn the amp off and reinsert V1. Amp off...repeat with V2 and so on. At some point I think the noise will disappear. This won't tell you exactly what is wrong, but it will lead to some idea of where the problem is. I am thinking that a tube socket has a problem....bad connection, crack, or maybe some dirt got in while you were changing tubes. Do you have any cleaner to spray in those sockets?

Thanks Wally, I tried all that and used the switch cleaner but no joy yet. I'm baffled.

Wally · March 18th, 2006, 03:02 PM

Quote:

Originally Posted by Scotland

Quote:

Originally Posted by Wally

Scotland, you need to do some basic research by pulling tubes to localize the problem. Start with V1..first on the right looking at the back of the amp. With the amp off, pull V1. Warm the amp up and bring it online. If the noise is no longer there, you have localized the problem. If the noise is still present, turn the amp off and reinsert V1. Amp off...repeat with V2 and so on. At some point I think the noise will disappear. This won't tell you exactly what is wrong, but it will lead to some idea of where the problem is. I am thinking that a tube socket has a problem....bad connection, crack, or maybe some dirt got in while you were changing tubes. Do you have any cleaner to spray in those sockets?

Thanks Wally, I tried all that and used the switch cleaner but no joy yet. I'm baffled.

So, did the noise ever go away? If so, at what point? If not....did the noise persist with all of the tubes out? I'm just curious here.
Side note...and not that it matters...but I am hesitant to replace all tubes at one time. I like to take note of what changes take place with the replacements. You can only do that when replacing preamps one at a time. I generally would replace the power tubes and the driver, take note, and then start at V1 and go throught the tube compliment tube by tube. When changing everything all at once, it is difficult to asses what changes took place and why.
I am thinking that if the noise persisted throughtout the test above, it is tech time. Probably is anyway. There may a bad connection on a socket connection. Curious problem....but nothing serious I would think. Does the amp still operate properly other than this noise?

Scotland · March 18th, 2006, 03:10 PM

Yes, it works perfectly apart from the noise. As you say, it is time for it to go to a tech, I'll let you know what the problem was once it's fixed. Good idea about changing the tubes in stages, I'll do that next time, thanks.

Dacious · March 19th, 2006, 03:32 AM

Wally beat me to it. I'd say you have an electro cap that's popped, or a bad joint caused by replacing the tubes, possibly on a tube pin.

Scotland · April 8th, 2006, 10:39 AM

Faulty hum balance control, replaced.
470 ohm resistor on V9 blown due to a chassis spring nut breaking and lodging itself across the resistor.
Everything else working perfectly and is sounding better than ever before with a complete new compliment of pre-amp and power tubes.
I'm a happy bunny again !! :D :D

dogman · April 8th, 2006, 11:50 AM

Good news! I love the JJ tubes. I replaced my EL84s with JJs, now it's time to order up some pre-amp tubes.

Scotland · April 8th, 2006, 12:23 PM

Quote:

Originally Posted by dogman

Good news! I love the JJ tubes. I replaced my EL84s with JJs, now it's time to order up some pre-amp tubes.

I love 'em, always have done. Try the 803s instead of the 12 AX7, the mids are very full and have a great sound, rounder with body if you know what I mean.

Wally · April 8th, 2006, 12:56 PM

Scotland, those hum balance controls can be a problem. Since we didn't know what amp was having problems, I didn't think about that one. those things are a trouble spot. IMO, it is best to take measurements and replace the pot with resistors to balance the heater filaments.
The loose nut....yeah, conductive pieces running loose in the circuit can cause all sorts of problems. I'm glad you got to the cure.

March 18th, 2006, 06:06 AM	#1 (permalink)
Scotland Poster Extraordinaire Join Date: Mar 2003 Location: Aberdeen, Scotland, Yewrup Age: 54 Posts: 6,612 3 Photos	Changed tubes...now a big problem-FIXED. I replaced all my pre amp and power tubes with J.J's. It then started buzzing very loudly even with nothing plugged in. I took them all out and put the old ones in again (also J.J's) but it's still buzzing just the same. I'm stumped here, what could have done this ? It was very very quiet before I did this now it's unuseable __________________ All those who believe in psycho-kinesis, raise my hand !

March 18th, 2006, 08:55 AM	#3 (permalink)
Mitch Roberts Tele-Meister Join Date: Mar 2003 Location: NYC Posts: 449	Does your amp have reverb? If so, check your reverb cables. If one develops a short it can buzz like crazy. Maybe you bumped them around when you changed the tubes. __________________ I think, therefore I jam.

March 18th, 2006, 09:20 AM	#4 (permalink)
Scotland Poster Extraordinaire Join Date: Mar 2003 Location: Aberdeen, Scotland, Yewrup Age: 54 Posts: 6,612 3 Photos	Pulled the reverb cables, still the same. Cleaned all the tube contacts and tightened them, still the same. This is strange. I bet it's something real simple. __________________ All those who believe in psycho-kinesis, raise my hand !

March 18th, 2006, 03:10 PM	#9 (permalink)
Scotland Poster Extraordinaire Join Date: Mar 2003 Location: Aberdeen, Scotland, Yewrup Age: 54 Posts: 6,612 3 Photos	Yes, it works perfectly apart from the noise. As you say, it is time for it to go to a tech, I'll let you know what the problem was once it's fixed. Good idea about changing the tubes in stages, I'll do that next time, thanks. __________________ All those who believe in psycho-kinesis, raise my hand !

March 19th, 2006, 03:32 AM	#10 (permalink)
Dacious Friend of Leo's Join Date: Mar 2003 Location: Godzone Posts: 2,623 35 Photos	Wally beat me to it. I'd say you have an electro cap that's popped, or a bad joint caused by replacing the tubes, possibly on a tube pin. __________________ My other Telecaster is a Thinline The Tele Bible, Ch 1, v 10 Love thy Telecaster, covet not thy neighbour's Strat!

March 18th, 2006, 06:35 AM	#2 (permalink)
Scott S Tele-Afflicted Join Date: Dec 2005 Location: SW CR IA US NA PE Age: 28 Posts: 1,916	Is it possible some of the tube contacts have gotten loose or dirty? I'm kind of grasping, but it might be worth a check...

March 18th, 2006, 12:10 PM	#5 (permalink)
Long_Ghost Tele-Meister Join Date: Aug 2003 Location: Texas Hillcountry Age: 59 Posts: 181 2 Photos	I am by no means an expert in such matters, but had a similar problem, and the solution appeared in the referenced article. Hoping this is of some help. LG http://groups.google.com/group/alt.g...f888287686a183

March 18th, 2006, 12:39 PM	#6 (permalink)
Wally Friend of Leo's Join Date: Mar 2003 Location: Lubbock, TX Posts: 4,212	Scotland, you need to do some basic research by pulling tubes to localize the problem. Start with V1..first on the right looking at the back of the amp. With the amp off, pull V1. Warm the amp up and bring it online. If the noise is no longer there, you have localized the problem. If the noise is still present, turn the amp off and reinsert V1. Amp off...repeat with V2 and so on. At some point I think the noise will disappear. This won't tell you exactly what is wrong, but it will lead to some idea of where the problem is. I am thinking that a tube socket has a problem....bad connection, crack, or maybe some dirt got in while you were changing tubes. Do you have any cleaner to spray in those sockets?

April 8th, 2006, 10:39 AM	#11 (permalink)
Scotland Poster Extraordinaire Join Date: Mar 2003 Location: Aberdeen, Scotland, Yewrup Age: 54 Posts: 6,612 3 Photos	Just got it back today from the tech. Faulty hum balance control, replaced. 470 ohm resistor on V9 blown due to a chassis spring nut breaking and lodging itself across the resistor. Everything else working perfectly and is sounding better than ever before with a complete new compliment of pre-amp and power tubes. I'm a happy bunny again !! :D :D __________________ All those who believe in psycho-kinesis, raise my hand !

April 8th, 2006, 11:50 AM	#12 (permalink)
dogman TDPRI Member Join Date: Nov 2005 Location: Boise, Idaho Posts: 43 3 Photos	Good news! I love the JJ tubes. I replaced my EL84s with JJs, now it's time to order up some pre-amp tubes.

April 8th, 2006, 12:56 PM	#14 (permalink)
Wally Friend of Leo's Join Date: Mar 2003 Location: Lubbock, TX Posts: 4,212	Scotland, those hum balance controls can be a problem. Since we didn't know what amp was having problems, I didn't think about that one. those things are a trouble spot. IMO, it is best to take measurements and replace the pot with resistors to balance the heater filaments. The loose nut....yeah, conductive pieces running loose in the circuit can cause all sorts of problems. I'm glad you got to the cure.