I understand that sometimes preamps have some DC in their output, and that the fix for this is to add some extra coupling caps to the output of the preamp or the input of the amp. I am unclear as to what kind of symptoms this will cause. I'm wondering if it's better to add them to the preamp or the amp, and if there's any downside of using them when they're not needed.
Background: I have a Van Alstine Super PAS Three that's 20+ years old. I used it with my Van Alstine U-70 until I built my ST-35 w/EFB (and dumped that U-70 as fast as I could). Later I got ahold of a pair of MK-IIIs that are essentially stock but with a lot of upgraded esoteric parts, and one of them makes some farting and popping sounds for a few minutes until it warms up. At the same time, I'm working on a rebuild of an old stock PAS2, on which I've been told I'll need to add some coupling caps after I remove the tone controls. So I'm feeling the need to get a better understanding of this area as to when this is needed - and whether I should add it to the preamps or the amps.
Background: I have a Van Alstine Super PAS Three that's 20+ years old. I used it with my Van Alstine U-70 until I built my ST-35 w/EFB (and dumped that U-70 as fast as I could). Later I got ahold of a pair of MK-IIIs that are essentially stock but with a lot of upgraded esoteric parts, and one of them makes some farting and popping sounds for a few minutes until it warms up. At the same time, I'm working on a rebuild of an old stock PAS2, on which I've been told I'll need to add some coupling caps after I remove the tone controls. So I'm feeling the need to get a better understanding of this area as to when this is needed - and whether I should add it to the preamps or the amps.
Last edited by daveshel on Wed Apr 13, 2016 9:54 am; edited 1 time in total