Help: Feedback Squeal with DIY HeadTap
Please forgive me. I'm not a sound guy. I'm just a bassist in the church band who likes DIY projects and is the only one in the church willing to try and design a cheap IEM system.
All that being said, I "designed" a headphone tap that is the exact same design as the Rolls PM52, except mine's mono. The first I built works beautifully and has helped three of our seven band members get IEMs.
However, I built a second one, and the only differences in this are: 1) I used a 3.5mm stereo jack, probably wired wrong, and 2) the way I hook it up.
I've attached a drawing (sorry, I'm not an artist) of how we run our sound, along with the schematic of the head tap. In the schematic, you'll see v1.0 of the 3.5mm jack wiring, and you'll see that I learned that I think I wired it wrong. Could the feedback squeal, aka, a VERY high pitched frequency, be PURELY from this issue?
If we unplug the 3.5mm cable from the Peavey VYPYR15 aux input, the squeal goes away.
Am I missing something absolutely obvious? I've been staring at this for days and can't come up with a reason.
Thanks in advance for any input you guys can provide.
EDIT: I just tried this same setup at home, but replaced the SoundCraft board, power amp, and Peavey wedge with my bass amp and cabinet. I can't get it to squeal, which makes me think we don't have a self-feeding feedback loop.
I've attached the new setup drawing. I can take pictures if that would help. (If I could at least REPLICATE the issue at home, I could troubleshoot it. However, since our church is not in a permanent location, I only get 10 minutes each Sunday morning to troubleshoot.)
Praise and Worship Band Bassists Club #1268 | Gallien-Krueger Official Club #995 | Texas Bassist Club #175