MasterKtulu
New member
Marshall JCM900 Problems…
Hi to all the tube amp gurus out there! I think I need your help.
I have a Marshall JCM900 MkIII Model 2501 (50W Master Volume 1x12 Combo) that I’ve had for over 16 years. I’m the original owner, it has never been modified, and is completely original (Tubes and all), except that I’ve removed the original still working Celestion G12T-75 Speaker with an Eminence Private Jack Speaker for a more vintage sound. I have taken really good care of the amp over the years and it has only seen a couple of jam sessions and no gigs. It has spent the majority of its life in my home playing at volumes between 3 and 4 (I think I’ve only pushed it to its maximum a handful of times). Currently, I play it with a Zoom G7.1ut effects console plugged into the Effects Return input in the back of the amp.
Problem 1: Now for about a year, every time I plug my guitar in the Preamp input in the front of the amp the volumes starts to cut off for a few seconds then come back again then cuts back down over and over again. After being powered up for a long time (About 20-30 minutes), it stops and I’m good to go. Are my Preamp Tubes done, or is it something else?
Problem 2: Yesterday, I was playing through my Zoom G7 plugged into the Effects Return input and after a half hour of playing my volume suddenly dropped by half. I continued playing for about 10 minutes waiting to see if the volume would go back up, it didn’t. Are my Power Tubes done, or is it something else?
Any help would be appreciated.
Hi to all the tube amp gurus out there! I think I need your help.
I have a Marshall JCM900 MkIII Model 2501 (50W Master Volume 1x12 Combo) that I’ve had for over 16 years. I’m the original owner, it has never been modified, and is completely original (Tubes and all), except that I’ve removed the original still working Celestion G12T-75 Speaker with an Eminence Private Jack Speaker for a more vintage sound. I have taken really good care of the amp over the years and it has only seen a couple of jam sessions and no gigs. It has spent the majority of its life in my home playing at volumes between 3 and 4 (I think I’ve only pushed it to its maximum a handful of times). Currently, I play it with a Zoom G7.1ut effects console plugged into the Effects Return input in the back of the amp.
Problem 1: Now for about a year, every time I plug my guitar in the Preamp input in the front of the amp the volumes starts to cut off for a few seconds then come back again then cuts back down over and over again. After being powered up for a long time (About 20-30 minutes), it stops and I’m good to go. Are my Preamp Tubes done, or is it something else?
Problem 2: Yesterday, I was playing through my Zoom G7 plugged into the Effects Return input and after a half hour of playing my volume suddenly dropped by half. I continued playing for about 10 minutes waiting to see if the volume would go back up, it didn’t. Are my Power Tubes done, or is it something else?
Any help would be appreciated.
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