LoveRocksRule
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- Oct 19, 2005
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ok guys and gals...
i have a marshall jcm2000tsl 3 channel 100watt head... i have had it for 6 years and in those years i have replaced all the valves on 2 different occasions... yeah i changed the enitre set of preamp and power amp valves at the same time, i just used marshalls own brand of matched valves which by the way wasnt very cheap to do!!!!! i dunno if u are supposed to replace the entire set like i done but anyway i have done this 2 times in its 6 years of life.... i just thought of it like guitar strings... like if u only change the string that snapped it sounds all bright and the other strings have that dead sound... i thought that valves worked in that same principal.... please excuse me if this is the wrong way as i am only 26 im still a young gun , and i never seeked any advice on it... so i just thought that replacing them all would be the best way to do the valve change....
for another 2 years it sat in a cuboard in my sisters house getting no use at all... i got it back a while ago and it was fine....
but just recently i have noticed that i will be playing away and then my volume all of a sudden goes to about half of what it was and the amp starts making a weird hissing sound...
this only happens once in a blue moon its not a frequent problem but when it does happen when i take a look down into the vents on the top of the head sometimes 2 of the EL34s are glowing like a lightbulb its usually just 1 of them but sometimes 2.... so i immedialty turn the amp off.....
leave it off for an hour or so... then fire her back on and shes fine... her sound is back to normal and the valves aren't glowing like light bulbs....
when it is happening and im standing infront of the amp looking down into the vents its always the 2 tubes at the right hand side that are the ones that are glowing......
does anyone know what the hell could be causing my head to be doing this....
is it just a simple case of replacing all the Poweramp Tubes. or is it a bias problem.... my flatmate is a qualified electrician so he knows about setting the BIAS on valve amps and we have a voltmeter to check the bias also......
as far as i understand so long as u understand electrics biasing a tube amp is relatively easy... not that i would perform it... it would be left for my Flatmate to do!!!!!
anyway any help on this problem would be gladly appreciated guys and girls.....
as i want my amp to be how she was when i first got her no problems at all.....
Dave
i have a marshall jcm2000tsl 3 channel 100watt head... i have had it for 6 years and in those years i have replaced all the valves on 2 different occasions... yeah i changed the enitre set of preamp and power amp valves at the same time, i just used marshalls own brand of matched valves which by the way wasnt very cheap to do!!!!! i dunno if u are supposed to replace the entire set like i done but anyway i have done this 2 times in its 6 years of life.... i just thought of it like guitar strings... like if u only change the string that snapped it sounds all bright and the other strings have that dead sound... i thought that valves worked in that same principal.... please excuse me if this is the wrong way as i am only 26 im still a young gun , and i never seeked any advice on it... so i just thought that replacing them all would be the best way to do the valve change....
for another 2 years it sat in a cuboard in my sisters house getting no use at all... i got it back a while ago and it was fine....
but just recently i have noticed that i will be playing away and then my volume all of a sudden goes to about half of what it was and the amp starts making a weird hissing sound...
this only happens once in a blue moon its not a frequent problem but when it does happen when i take a look down into the vents on the top of the head sometimes 2 of the EL34s are glowing like a lightbulb its usually just 1 of them but sometimes 2.... so i immedialty turn the amp off.....
leave it off for an hour or so... then fire her back on and shes fine... her sound is back to normal and the valves aren't glowing like light bulbs....
when it is happening and im standing infront of the amp looking down into the vents its always the 2 tubes at the right hand side that are the ones that are glowing......
does anyone know what the hell could be causing my head to be doing this....
is it just a simple case of replacing all the Poweramp Tubes. or is it a bias problem.... my flatmate is a qualified electrician so he knows about setting the BIAS on valve amps and we have a voltmeter to check the bias also......
as far as i understand so long as u understand electrics biasing a tube amp is relatively easy... not that i would perform it... it would be left for my Flatmate to do!!!!!
anyway any help on this problem would be gladly appreciated guys and girls.....
as i want my amp to be how she was when i first got her no problems at all.....
Dave