Luke Duke
New member
Alright so a quick bit of history.
I got this amp (101B) 5yrs ago. The amp landed with 6 Tung Sol ECC803S and 4 =C= EL34s. A month into ownership the =C= in V7 blew up and took the bias supply resistor with it. I changed them out for Vishays I saw mentioned here (IIRC) and I replaced the power tubes with EH 6CA7s and rolled on. I've had a few HT fuses blow randomly, but nothing too crazy, I chalk it up to dirty power.
That said...this last week I blew a mains fuse just as V9 and V10 were red-plating. I smelled the "fuse smell" went to look and then POP! So, I changed the fuse, stole a pair of 6CA7s from my 2204, and fired it back up...same thing. I opened it up and nothing burned looking...no smell, nothing. Tuesday on a whim I switched around the 6CA7s that had been in it, and the red-plating moved with the tubes I had problems with. Also, the red-plating tubes have the blue halo in the glass, but the other two do not. The 2204 6CA7s also had the blue halo. So I'm wondering if it's possible those tubes just are not "in spec" for that amp anymore? Should I look for something else, or just get a new quad of tubes and roll on?
Oh, and I've attached a pic of the power supply board, it also shows it's 6.0...whatever that means.
Thanks in advance for the help!
Luke
I got this amp (101B) 5yrs ago. The amp landed with 6 Tung Sol ECC803S and 4 =C= EL34s. A month into ownership the =C= in V7 blew up and took the bias supply resistor with it. I changed them out for Vishays I saw mentioned here (IIRC) and I replaced the power tubes with EH 6CA7s and rolled on. I've had a few HT fuses blow randomly, but nothing too crazy, I chalk it up to dirty power.
That said...this last week I blew a mains fuse just as V9 and V10 were red-plating. I smelled the "fuse smell" went to look and then POP! So, I changed the fuse, stole a pair of 6CA7s from my 2204, and fired it back up...same thing. I opened it up and nothing burned looking...no smell, nothing. Tuesday on a whim I switched around the 6CA7s that had been in it, and the red-plating moved with the tubes I had problems with. Also, the red-plating tubes have the blue halo in the glass, but the other two do not. The 2204 6CA7s also had the blue halo. So I'm wondering if it's possible those tubes just are not "in spec" for that amp anymore? Should I look for something else, or just get a new quad of tubes and roll on?
Oh, and I've attached a pic of the power supply board, it also shows it's 6.0...whatever that means.
Thanks in advance for the help!
Luke
