Hello all -- My son has a tubed guitar amp. Apparently after 3 months - he blew the tubes. There are 4 of them. Is there a way to determine which ones are dead? Anyone know of a nice tube for an amp - and how I might determine if that tube is something that would 'fit' the amp? thx. tim
Tubes & guitar amps
- Thread starter timm
- Start date
Help Support MartinLogan Audio Owners Forum:
Valve Guitar Amp
Hi what amp is it?
is it a Mono amp?
I think from memory stereo amps normally have four valves 2 per channel. 2 for the preamp stage and 2 for the power amp section. When they go they normally go white and powdery inside. Do they sound like a filament is rattling around inside? also does the amp power up?
It's worth remembering a shut down procedure valves are quite delicate and you should wait for the valves to cool down before moving the amp about 5 minutes. Some amps have 2 switches, first switch turns the mains on and powers up the transformer and the second switch activates the valves.
I use Watford valves for my gear (and hifi) you could ring or email them and they could probably diagnose it for you.
http://www.watfordvalves.com/
cheers Matt. :rocker:
Hi what amp is it?
is it a Mono amp?
I think from memory stereo amps normally have four valves 2 per channel. 2 for the preamp stage and 2 for the power amp section. When they go they normally go white and powdery inside. Do they sound like a filament is rattling around inside? also does the amp power up?
It's worth remembering a shut down procedure valves are quite delicate and you should wait for the valves to cool down before moving the amp about 5 minutes. Some amps have 2 switches, first switch turns the mains on and powers up the transformer and the second switch activates the valves.
I use Watford valves for my gear (and hifi) you could ring or email them and they could probably diagnose it for you.
http://www.watfordvalves.com/
cheers Matt. :rocker:
thanks for the reply matt -- It is a line6 amp. They make 1 amp with tubes that I know of... Yes, there are 4 tubes. The guys at guitar center say we should 'just replace all of them'. But, I'm not sure if they are giving me a line or not. The amp itself cost about 850 - and to get the 'better' tubes that last longer - they recommend the $60 X 4 tubes. I don't know -- I have to talk to my son to see what is up with it. But, once I get it - I'll take a look. This amp has a standby mode - which I believe it goes into first prior to shutdown etc.... They claim the stock tubes will go every 2-3 months...which is not something my jobless 15 year old son had counted on. The 'better' ones supposedly last 6 months - which still seems to be a bit ridiculous... My brother had an old tubed amp back in the 60's - and it NEVER blew a tube.... so is this typical of tube amps today - that they blow tubes every 3-6 months? He plays it - but, maybe 3 times a week @ 2hrs/time at most. He has another amp (marshall half stack) that he uses as well...So, the useage is split between the amps.
"Hello all -- My son has a tubed guitar amp. Apparently after 3 months - he blew the tubes. There are 4 of them. Is there a way to determine which ones are dead? Anyone know of a nice tube for an amp - and how I might determine if that tube is something that would 'fit' the amp? thx. tim "
Fault finding,
If the valves are paired you could alternate/swap them around.
Check all fuses.
look out / listen out for any relays switching or not.
If you open up the amp look for any scorched components / or scorched board.
Check soilder joints "they should be shiny" dry joints will be dull.
Make sure any removable components are in home, might be a good idea to remove in and out a few times, so you know you have a good mating connection.
"They claim the stock tubes will go every 2-3 months"
and as for replacing valves every 3 months what a load rubbish! i have a marshall JMP1 valve pre amp from 1990 still going strong! never changed the valves once any way good luck.
Matt.
Fault finding,
If the valves are paired you could alternate/swap them around.
Check all fuses.
look out / listen out for any relays switching or not.
If you open up the amp look for any scorched components / or scorched board.
Check soilder joints "they should be shiny" dry joints will be dull.
Make sure any removable components are in home, might be a good idea to remove in and out a few times, so you know you have a good mating connection.
"They claim the stock tubes will go every 2-3 months"
and as for replacing valves every 3 months what a load rubbish! i have a marshall JMP1 valve pre amp from 1990 still going strong! never changed the valves once any way good luck.
Matt.
Ok - another question.... what does 'biasing' the tubes mean... Is this something that can be done at home? Apparently, it looks like 1 of his 2 power tubes was blown...... Could I just replace the 1 tube - and walk away from it... They are suggesting to just replace all of them (they probably have 50 hrs of play on them).... thx. tim.
Pcar928fan
Well-known member
Tim,
I have a Marshall JCM600 (602 model w/ the dual 12" speakers) and I have only had to replace my power tubes ONCE in nearly 10 YEARS!! It does not get moved around though and I don't play at ear splitting volumes either. I ALWAYS power it up first with the standby OFF (or would that actually be ON???) so that no sound comes out. Then once the tubes have had a few minutes to warm up I switch on the standby switch and do all the playing I want. Then I hit the standby switch again and let the mains have time to normalize (from a temp perspective) for a minute or two or three, then turn off the main power. The only time the tubes blew was when a kid was taking care of my dogs while I was on vacation and I came home to see that my amp was ON! I was NOT amused and needless to say that boy never entered my house again.
Hope you get it all worked out.
James
I have a Marshall JCM600 (602 model w/ the dual 12" speakers) and I have only had to replace my power tubes ONCE in nearly 10 YEARS!! It does not get moved around though and I don't play at ear splitting volumes either. I ALWAYS power it up first with the standby OFF (or would that actually be ON???) so that no sound comes out. Then once the tubes have had a few minutes to warm up I switch on the standby switch and do all the playing I want. Then I hit the standby switch again and let the mains have time to normalize (from a temp perspective) for a minute or two or three, then turn off the main power. The only time the tubes blew was when a kid was taking care of my dogs while I was on vacation and I came home to see that my amp was ON! I was NOT amused and needless to say that boy never entered my house again.
Hope you get it all worked out.
James
Similar threads
