GreenFog_Studios
Active member
Ten years ago I bought my first RCA vintage tube pre amp and fell in love with them and I have gotten into a lot of the old RCA stuff. I bought it at Future Music in L.A. off Sunset. It used to belong to Mark Sampson of Matchless amplifiers and had ben modded. If you are looking at the pre amp with the volume knob in front, the middle tube closest to you which in a stock version is the 1620 on the right, has been replaced with an unmarked tube that is the width of the 6X5GT and about as tall as a 6L6. The tube has no markings and no longer lights up so I can't test it, measure the voltages and ID the mystery tube.
Where the hole for the wire for the 1620 that has been swapped, there is a 5 way rotary pot which changes the character of the pre amp similar to a vari-tone guitar circuit and near the volume knob is a tone sweep pot.
The BA2C sounded great until the tube started to die and now it doesn't pass signal. So I'm pretty sure that the issue is the tube. That being said does anyone know if the eq mods are related to the mystery tube and more importantly any ideas as to what the mystery tube is?
Where the hole for the wire for the 1620 that has been swapped, there is a 5 way rotary pot which changes the character of the pre amp similar to a vari-tone guitar circuit and near the volume knob is a tone sweep pot.
The BA2C sounded great until the tube started to die and now it doesn't pass signal. So I'm pretty sure that the issue is the tube. That being said does anyone know if the eq mods are related to the mystery tube and more importantly any ideas as to what the mystery tube is?