11-09-2019, 01:07 PM
Hi Nortonz!
A Jackson 648 is an emission style tester, so if those tubes don't pass the emission test on the 648, they are probably bad. However, the best way to know for SURE is to put them in a working radio and compare the performance of the radio. Both R.L. Drake and Collins radio suggested that method to be SURE that the tube was indeed bad. I wouldn't pitch the XXL's until I had a working set to plug them in to, so as to make a definite determination. BTW, if memory serves, an XXL is the same as a 7A4. But that is the only other sub for an XXL.
A Jackson 648 is an emission style tester, so if those tubes don't pass the emission test on the 648, they are probably bad. However, the best way to know for SURE is to put them in a working radio and compare the performance of the radio. Both R.L. Drake and Collins radio suggested that method to be SURE that the tube was indeed bad. I wouldn't pitch the XXL's until I had a working set to plug them in to, so as to make a definite determination. BTW, if memory serves, an XXL is the same as a 7A4. But that is the only other sub for an XXL.
Kim Herron W8ZV
w8zv at goldenradioservice.com
1-616-677-3706
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