Cam Posted July 14, 2010 Report Share Posted July 14, 2010 (edited) Just before I was playing through my Epi Valve Junior stack (at full volume) when all of a sudden it got really quite and then there was no volume and its the same for all of my guitars. It's not the cable either since the amp makes a 'crackling' sound both when plug into a guitar and with the cable taken out. My other problem is that I don't have another speaker cabinet to try the head with to work out if its a blown speaker or something wrong with the head. It is still under warranty so I can send it back, but I was wondering if there was anyway to tell if it is just a simple fix like replacing a tube or something? Also, the amp is only about 2/3 years old. Edited July 14, 2010 by Cam Quote Link to comment Share on other sites More sharing options...
Samba Pa Ti Posted July 14, 2010 Report Share Posted July 14, 2010 could be a tube, i replaced the tubes on my epi as they sounded muddy anyway. Quote Link to comment Share on other sites More sharing options...
borge Posted July 14, 2010 Report Share Posted July 14, 2010 Try changing the tubes if you have some on hand, otherwise take it back, you shouldn't have to fix an amp less than a year old and trying to will void your warranty..... Quote Link to comment Share on other sites More sharing options...
Cam Posted July 14, 2010 Author Report Share Posted July 14, 2010 Sorry, I meant its two or three years old, not two thirds. I had a go plugging into it now and there's no sound whatsoever coming from it, not even the usual slight buzz. Quote Link to comment Share on other sites More sharing options...
borge Posted July 14, 2010 Report Share Posted July 14, 2010 Oh ok, though, my point still stands as its under warranty. It's a very simple amp and would be easy to fault find if you're that way inclined. Schem: http://www.muzique.com/news/images/Epi1.gif Quote Link to comment Share on other sites More sharing options...
Tim37 Posted July 14, 2010 Report Share Posted July 14, 2010 if ya want to fix it yourself theres a ton of parts out there for up grades or just parts removed from good amps on ebay. but Like borg said its still under warrenty make them fix it. Quote Link to comment Share on other sites More sharing options...
Workingman Posted July 14, 2010 Report Share Posted July 14, 2010 If it has a speaker out jack, you could always plug a set of headphones in. Just to test, not to play for any time. Quote Link to comment Share on other sites More sharing options...
WezV Posted July 14, 2010 Report Share Posted July 14, 2010 have a sneaky look at the valves whilst its on and see if you can spot a problem one. there should be a warm orangey glow from each one. you should be able to see through the back panel on a valve jnr if one has blown i would just replace it with an upgrade rather than let them put another cheapy back in. these small amps dont need biasing so its just pull out the old and put the new in - if thats all it is Quote Link to comment Share on other sites More sharing options...
borge Posted July 14, 2010 Report Share Posted July 14, 2010 If it has a speaker out jack, you could always plug a set of headphones in. Just to test, not to play for any time. Headphone power ratings are in the range of milliWatts, they would blow very very early on the volume dial, before '1' i'd guess. Even if they didn't blow, The VJ expects a 4-16 ohm load, The impedance of headphones is often on the XXXohms range, not good for the VJ's OT... Quote Link to comment Share on other sites More sharing options...
Cam Posted July 15, 2010 Author Report Share Posted July 15, 2010 (edited) have a sneaky look at the valves whilst its on and see if you can spot a problem one. there should be a warm orangey glow from each one. you should be able to see through the back panel on a valve jnr if one has blown i would just replace it with an upgrade rather than let them put another cheapy back in. these small amps dont need biasing so its just pull out the old and put the new in - if thats all it is Can't believe I forgot that one. The only valve I can see has the orangey glow your talking about instead of its normal bluey glow, so I'll change that one with a better quality one. Edited July 15, 2010 by Cam Quote Link to comment Share on other sites More sharing options...
WezV Posted July 15, 2010 Report Share Posted July 15, 2010 should be two should there not, a 12ax7 and an el84 - possibly with a metal cover over one though an orangey glow is not bad - that one probably works... you can remove the metal cover and see if the other one is working and work through this http://www.geofex.com/ampdbug/ampdebug.htm Quote Link to comment Share on other sites More sharing options...
Samba Pa Ti Posted July 15, 2010 Report Share Posted July 15, 2010 didnt know tubes glowed blue :S never seen that... maybe this is where all the gain of the amp was being lost ? (referring to your other thread) Quote Link to comment Share on other sites More sharing options...
Cam Posted July 15, 2010 Author Report Share Posted July 15, 2010 (edited) should be two should there not, a 12ax7 and an el84 - possibly with a metal cover over one though an orangey glow is not bad - that one probably works... you can remove the metal cover and see if the other one is working and work through this http://www.geofex.com/ampdbug/ampdebug.htm there is one in a metal case that I haven't looked at yet. Also, what is causing the other tube to glow orange instead of the blue it was glowing before the amp stopped working? Edited July 15, 2010 by Cam Quote Link to comment Share on other sites More sharing options...
WezV Posted July 15, 2010 Report Share Posted July 15, 2010 the blue may have been the issue - all mine glow orange, like this Quote Link to comment Share on other sites More sharing options...
Tim37 Posted July 16, 2010 Report Share Posted July 16, 2010 some glow blue but i cant remember why. Quote Link to comment Share on other sites More sharing options...
Samba Pa Ti Posted July 16, 2010 Report Share Posted July 16, 2010 some glow blue but i cant remember why. sometimes its normal, but it can be because they are "gassy" or leaky, googling brings up this > http://www.netads.com/~meo/Guitar/Tubes/blue_glow.html considering something is wrong with the amp that might be the cause, but the only way to tell is to swap em and see if it comes back to life, there could be allsorts wrong with an epi amp they arnt very well made but still sound good when driven hard. Quote Link to comment Share on other sites More sharing options...
Cam Posted July 16, 2010 Author Report Share Posted July 16, 2010 the blue may have been the issue - all mine glow orange, like this The tubes have always glowed blue since new and now glow orange. I will definitely change the tubes, and then if something is still wrong, my dad used to have a business which fixed valve radios and amplifiers etc, so he will most likely know whats going on inside after having a look. Quote Link to comment Share on other sites More sharing options...
Cam Posted July 23, 2010 Author Report Share Posted July 23, 2010 Found the problem It was just a burnt out resistor, easy fix. Quote Link to comment Share on other sites More sharing options...
KeithHowell Posted July 26, 2010 Report Share Posted July 26, 2010 A burnt out resistor would be indicative, to me, of something else wrong which caused the wattage rating on the resistor to be exceeded hence burning it out. I would suggest you check the voltage across the resistor once it has been replaced and see if it is within spec. Keith Quote Link to comment Share on other sites More sharing options...
Cam Posted July 26, 2010 Author Report Share Posted July 26, 2010 Yeah I will try that. The amp now just makes a loud crackle noise when turned on, so I don't know if that's because of the original problem or one of the small mods we (shouldn't have done) did. My dad (electrical engineer/ amp/ radio fixer/ whatever he is) said that the small mods should be fine and he also recommended that we check the voltage across the resistor and see if it is within spec. Hopefully all is still good Quote Link to comment Share on other sites More sharing options...
Samba Pa Ti Posted July 26, 2010 Report Share Posted July 26, 2010 did you try swapping the tubes out ? Quote Link to comment Share on other sites More sharing options...
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