ingeneri Posted July 28, 2012 Share Posted July 28, 2012 So, I moved to Malaysia a year ago and shipped my DRRI. It's US voltage (115), though everything here is 220. Whenever I play through the amp, I get a few minutes of perfect tone. But then the volume dies and the tone gets muffled. The odd part is, it goes back to normal if I switch the standby switch off then on. But then the whole cycle repeats itself. I just changed Preamp tubes before moving, but am wondering if this is a sign of tube failure. Or is it a likely side effect of the different electrical frequency despite my using a hefty transformer. All thoughts appreciated. Link to comment Share on other sites More sharing options...
Guest HRB853370 Posted July 28, 2012 Share Posted July 28, 2012 So, I moved to Malaysia a year ago and shipped my DRRI. It's US voltage (115), though everything here is 220. Whenever I play through the amp, I get a few minutes of perfect tone. But then the volume dies and the tone gets muffled. The odd part is, it goes back to normal if I switch the standby switch off then on. But then the whole cycle repeats itself. I just changed Preamp tubes before moving, but am wondering if this is a sign of tube failure. Or is it a likely side effect of the different electrical frequency despite my using a hefty transformer. All thoughts appreciated. Cant help you on your problem, but I have always wanted to live in Malaysia. Link to comment Share on other sites More sharing options...
DetroitBlues Posted July 28, 2012 Share Posted July 28, 2012 The first rule of thumb when troubleshooting tube amps.... Check your tubes... Sounds like one is failing. Link to comment Share on other sites More sharing options...
Steiner Posted July 28, 2012 Share Posted July 28, 2012 I think the world is wired at 60Hz so there shouldn't be an electrical frequency issue. However doubling the voltage across he trannys is not a good idea. Can you get a voltage transformer or variac to get back to 110? You also have an option of replacing the 110V trannys with 220V. Link to comment Share on other sites More sharing options...
SouthpawGuy Posted July 28, 2012 Share Posted July 28, 2012 So, I moved to Malaysia a year ago and shipped my DRRI. It's US voltage (115), though everything here is 220. Whenever I play through the amp, I get a few minutes of perfect tone. But then the volume dies and the tone gets muffled. The odd part is, it goes back to normal if I switch the standby switch off then on. But then the whole cycle repeats itself. I just changed Preamp tubes before moving, but am wondering if this is a sign of tube failure. Or is it a likely side effect of the different electrical frequency despite my using a hefty transformer. All thoughts appreciated. So you're using a 110v amp in a 220v area ? I'm surprised it works at all, I'd have thought you would need a transformer of some sort to run it ? Link to comment Share on other sites More sharing options...
DetroitBlues Posted July 28, 2012 Share Posted July 28, 2012 I assumed he already had some sort of power adapter.... Link to comment Share on other sites More sharing options...
pegleg32 Posted July 28, 2012 Share Posted July 28, 2012 He did mention he had a transformer, so likely something else? Link to comment Share on other sites More sharing options...
kbp810 Posted July 28, 2012 Share Posted July 28, 2012 By "hefty transformer", I assume you're already using a step down transformer in front of it - I would assume that it's 60Hz as well, though if not, a parasitic oscillation could be possible, which could in turn potentially cause symptoms such as what you've described... though my initial guess would be failing power tubes and/or failing screen resistor; sometime that may work at first, but then begin to fail as it comes to operating temperature. I would start with a known working pair of power tubes and then go from there If you are not using a transformer or variac to step down the voltage, then cease and desist immediately and get one (or swap the transformer in the amp for a 220v primary), and then hope for the best that no damage has been done Link to comment Share on other sites More sharing options...
SouthpawGuy Posted July 28, 2012 Share Posted July 28, 2012 He did mention he had a transformer, so likely something else? My bad. Todays Speed Reader award goes to me then Link to comment Share on other sites More sharing options...
H Posted July 28, 2012 Share Posted July 28, 2012 I think the world is wired at 60Hz so there shouldn't be an electrical frequency issue. Actually, the world is mostly 50hz: http://en.m.wikipedia.org/wiki/Utility_frequency Link to comment Share on other sites More sharing options...
t0aj15 Posted July 29, 2012 Share Posted July 29, 2012 Insufficient data in the original post. If your trying to run an amp designed off of American power-115V/60hz on Euro power which is 220V/50hz I have NO doubt what-so-ever that your having problems. Are you using a step up/down transformer of any sort? Link to comment Share on other sites More sharing options...
bolero Posted July 29, 2012 Share Posted July 29, 2012 what they said, I wouldn't use it without a stepdown transformer between the wall & your amp it is not like most computers which now have an autoswitching power supply it is possible your amp has a 220v setting on the power transformer...they do sell Fender amps in Europe etc but you'd probably have to manually switch it ps if you're using one of those small flimsy power converters that will not do the job...you need a proper transformer like this, rated for whatever the back of your amps says x2 I have one of these I need to use for my old Marshall, which is only tapped for 220v ps this link has some other useful info too http://www.gson.org/stepdown/ Link to comment Share on other sites More sharing options...
ingeneri Posted July 29, 2012 Author Share Posted July 29, 2012 Thanks guys. For the record, I'm using a very substantial power down transformer. US voltage amps are completely inoperable at 220v, the fuse blows immediately. What I have is a periodic collapse in volume and clarity. The odd part, to me, is that it seems to rectify itself when switching the standby switch off and on. I had heard you could still have issues here with tube amps, but not solid state, despite using the transformer. Though I never had this issue with this amp in China or South Africa (also both 220v). Would it have to be the power tubes? Or would a bad Preamp tube cause similar symptoms? Link to comment Share on other sites More sharing options...
tulk1 Posted July 29, 2012 Share Posted July 29, 2012 Had a lead player who's amp did that sometimes. New power tubes solved. Link to comment Share on other sites More sharing options...
kbp810 Posted July 30, 2012 Share Posted July 30, 2012 Would it have to be the power tubes? Or would a bad Preamp tube cause similar symptoms? It's possible, but seems less likely to me; power tubes or rectifier tube would still be my top two suspects Link to comment Share on other sites More sharing options...
HANGAR18 Posted August 23, 2012 Share Posted August 23, 2012 It's possible, but seems less likely to me; power tubes or rectifier tube would still be my top two suspects (At the risk of starting a sub thread of which tubes are better...) The only thing I know about tubes is that (according to my specific GC guitar guru) the tubes made in Russia are supposed to be the best. I guess the point I'm trying to make is maybe there is a better brand of tube which can be installed. Or maybe all the tubes should be made by the same company in order to be balanced or something. IDK, that's all I got. My VOX amp has a single tube in it and the aforementioned guru sold me a GT (Groove Tubes) Silver Series tube. As in www.groovetubes.com. Link to comment Share on other sites More sharing options...
DetroitBlues Posted August 23, 2012 Share Posted August 23, 2012 (At the risk of starting a sub thread of which tubes are better...) The only thing I know about tubes is that (according to my specific GC guitar guru) the tubes made in Russia are supposed to be the best. I guess the point I'm trying to make is maybe there is a better brand of tube which can be installed. Or maybe all the tubes should be made by the same company in order to be balanced or something. IDK, that's all I got. My VOX amp has a single tube in it and the aforementioned guru sold me a GT (Groove Tubes) Silver Series tube. As in www.groovetubes.com. Not a lot of choices either... Russia or China... Link to comment Share on other sites More sharing options...
rooster Posted August 27, 2012 Share Posted August 27, 2012 Could also be as simple as a dirty tube socket. It sounds like one of the power tubes is cutting out, or 1/2 of the phase inverter. rooster. Link to comment Share on other sites More sharing options...
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