whetherhead
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- Feb 18, 2012
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Hello everyone.
I joined this forum looking to find info on a specific problem with my amp head. The problem seems to have escalated quite a bit today and I've pretty much decided to take the head into a repair shop at this point but wanted to run the issue by everyone on the forum here. Mainly just so I know what to expect when I take it in, but also because I was thinking about doing a few slightly costly repairs at home first (replacing all the tube) and would like to hear if anyone feels that it would be a waste of time and money. Let me apologize now if this gets a little longwinded.
First of I'll give you some info on my amp. It's a two channel Triple Rectifier Solo Head that was made in May of 2000 I think. I bought it used from an acquaintance close to ten years ago. While I've been intending on doing so for quite some time now, I've yet to replace any of the tubes in it. The initial problem that I was having was with the effects loop (EL). I never even touched the EL for a maybe the first five years or so that I had the head. At that point I decided to play with it but found that when ever I engaged any of the EL selections other than Ext SW (Red Auto, Org Auto, Loop On Org & Red and Loop Bypass), I would get a loud hum and nothing else. It didn't matter whether anything was connected to the send and/or return path nor if a guitar was plugged in. Adjusting any of the knobs in the front of the amp, including the Loop Active Master (LAM) knob had no affect on the tone or volume of the hum. It was consistent no matter what parameter was changed. Normally, after hearing this hum I would turn the loop off just to make the hum go away.
I brought the head home recently and was testing it today. I powered it on without connecting anything else to it and engaged an EL selection (Red Auto I think if it helps) and noticed an electric sound buzz coming from around the transformer located behind the front input jack. The intensity of this buzz was affected by the LAM knob in the front of the head. It would get louder as the knob was turned up. As I stated earlier, I would normally disengage the loop if only to make the noise go away. Today I left it on for a while as I adjusted the LAM knob and the send and return knobs in the back. Within a minute but probably less than 30 seconds, a few of the tubes started to spark blue inside them (I'm not sure if this is arcing). The tubes that seem to be affected are [viewing from the back, left to right] the very last 5U4G rectifier tube (this is the main one affected) and the third 6L6 tube. This was all accompanied by a little bit of smoke coming from the mentioned tubes. Before I could power of the amp, the fuse had blown. Of course, the amp would not power on now. I replaced the fuse and powered the amp on making sure that the EL was not engaged, leaving standby off. After a few seconds, the last 5U4G rectifier tube sparked a bit but then remained fine, glowing as usual. Then I flipped the standby switch to on. Both tubes mentioned above started sparking (a few other 6L6 tubes [4, 5 and 6] may have sparked a little too). Like before, after a short time, the fuse blew. I repeated the process just to be sure and yielded the same results.
I didn't mention it above but feel that it would be helpful to note that the 12AX7 tubes do not seem to be affected.
Initially, after the first fuse blew, I was thinking that the tubes had just gone bad and was causing the problem with the fuse but after doing the further testing and having the fuses keep destroying themselves, I'm not sure. I'm not a master when it comes to electronics but am not completely ignorant either. In a situation like this, though, I wouldn't consider myself above a novice and appreciate the information of those with more knowledge then I have.
Any insight into either of these problems would be appreciated. Thanks in advance.
P.S. I examined the amps circuitry and didn't see any signs of burnt resistors or capacitors but I fear that the problem is with the transformer. After reading over the forum regarding my initial EL problem, I was thinking that maybe a previous owner had tried to mod it but everything looks
accurate on it based on the pictures I've seen. The solder joints look clean and pretty much what I would expect from a factory job as well. That's not really important right now though. This new issue is my main concern. I'm pretty certain I will have the amp examined even if replacing the tubes is all that's necessary to fix this current issue.
If you would like any pictures or video of this problem occuring, let me know and I'll post it as soon as possible.
I joined this forum looking to find info on a specific problem with my amp head. The problem seems to have escalated quite a bit today and I've pretty much decided to take the head into a repair shop at this point but wanted to run the issue by everyone on the forum here. Mainly just so I know what to expect when I take it in, but also because I was thinking about doing a few slightly costly repairs at home first (replacing all the tube) and would like to hear if anyone feels that it would be a waste of time and money. Let me apologize now if this gets a little longwinded.
First of I'll give you some info on my amp. It's a two channel Triple Rectifier Solo Head that was made in May of 2000 I think. I bought it used from an acquaintance close to ten years ago. While I've been intending on doing so for quite some time now, I've yet to replace any of the tubes in it. The initial problem that I was having was with the effects loop (EL). I never even touched the EL for a maybe the first five years or so that I had the head. At that point I decided to play with it but found that when ever I engaged any of the EL selections other than Ext SW (Red Auto, Org Auto, Loop On Org & Red and Loop Bypass), I would get a loud hum and nothing else. It didn't matter whether anything was connected to the send and/or return path nor if a guitar was plugged in. Adjusting any of the knobs in the front of the amp, including the Loop Active Master (LAM) knob had no affect on the tone or volume of the hum. It was consistent no matter what parameter was changed. Normally, after hearing this hum I would turn the loop off just to make the hum go away.
I brought the head home recently and was testing it today. I powered it on without connecting anything else to it and engaged an EL selection (Red Auto I think if it helps) and noticed an electric sound buzz coming from around the transformer located behind the front input jack. The intensity of this buzz was affected by the LAM knob in the front of the head. It would get louder as the knob was turned up. As I stated earlier, I would normally disengage the loop if only to make the noise go away. Today I left it on for a while as I adjusted the LAM knob and the send and return knobs in the back. Within a minute but probably less than 30 seconds, a few of the tubes started to spark blue inside them (I'm not sure if this is arcing). The tubes that seem to be affected are [viewing from the back, left to right] the very last 5U4G rectifier tube (this is the main one affected) and the third 6L6 tube. This was all accompanied by a little bit of smoke coming from the mentioned tubes. Before I could power of the amp, the fuse had blown. Of course, the amp would not power on now. I replaced the fuse and powered the amp on making sure that the EL was not engaged, leaving standby off. After a few seconds, the last 5U4G rectifier tube sparked a bit but then remained fine, glowing as usual. Then I flipped the standby switch to on. Both tubes mentioned above started sparking (a few other 6L6 tubes [4, 5 and 6] may have sparked a little too). Like before, after a short time, the fuse blew. I repeated the process just to be sure and yielded the same results.
I didn't mention it above but feel that it would be helpful to note that the 12AX7 tubes do not seem to be affected.
Initially, after the first fuse blew, I was thinking that the tubes had just gone bad and was causing the problem with the fuse but after doing the further testing and having the fuses keep destroying themselves, I'm not sure. I'm not a master when it comes to electronics but am not completely ignorant either. In a situation like this, though, I wouldn't consider myself above a novice and appreciate the information of those with more knowledge then I have.
Any insight into either of these problems would be appreciated. Thanks in advance.
P.S. I examined the amps circuitry and didn't see any signs of burnt resistors or capacitors but I fear that the problem is with the transformer. After reading over the forum regarding my initial EL problem, I was thinking that maybe a previous owner had tried to mod it but everything looks
accurate on it based on the pictures I've seen. The solder joints look clean and pretty much what I would expect from a factory job as well. That's not really important right now though. This new issue is my main concern. I'm pretty certain I will have the amp examined even if replacing the tubes is all that's necessary to fix this current issue.
If you would like any pictures or video of this problem occuring, let me know and I'll post it as soon as possible.
