Hi guys,
Just finished putting together a two-channel tube preamp based on Hampton's schematic. I'm getting way too much AC signal hitting the first grid (should be .48V, but it is 7.98!). So, the input is overdriven and as I turn up the volume (stepped attenuator) it quickly distorts and gets nasty.
The strange thing is that the output peaks at -15db (should be 1.24V, but reads around 41v).
Any thoughts? I'm pulling my hair out.
Here are some videos of the problem and schematic (330 ohm grid stoppers added).
Video 1: https://youtu.be/1iKeQzl_pdQ
Video 2: https://youtu.be/4H5U2fxRUKE
Video 3 (vocal sample, phantom power is fixed): https://youtu.be/NLa-8qjbzFs
Just finished putting together a two-channel tube preamp based on Hampton's schematic. I'm getting way too much AC signal hitting the first grid (should be .48V, but it is 7.98!). So, the input is overdriven and as I turn up the volume (stepped attenuator) it quickly distorts and gets nasty.
The strange thing is that the output peaks at -15db (should be 1.24V, but reads around 41v).
Any thoughts? I'm pulling my hair out.
Here are some videos of the problem and schematic (330 ohm grid stoppers added).
Video 1: https://youtu.be/1iKeQzl_pdQ
Video 2: https://youtu.be/4H5U2fxRUKE
Video 3 (vocal sample, phantom power is fixed): https://youtu.be/NLa-8qjbzFs