Single Coil Pickups, "Hearing Loop" Room Feeback

[mellamoyo]

So tonight, I was practicing in the Chapel at my college for a service Friday. I have a Fender Zone bass--a PJ setup. When I had any of the P selected in the blend, the amp would emit high-pitched feedback.

So I swapped that amp out for my more current Fender Bassman 150. Instead of feeding back, when selecting P at all, the vocalists and other instruments would come through my amp.

Now, the chapel does have a "Hearing Loop" ( see here ), and the pianist suggested that the single coil P pickup couldn't handle the hearing loop and was picking up the other sounds, which would explain why the other amp was feeding back also.

Does this make sense/anyone had similar experience?

 

[t bake]

Thinking the pick up thing may have some thing, Im thinking placement of amp and or shielding may be needed. Ever have the radio come through amp move it a little and it is gone? same theory talk to the mfg of loop equip.transmitter freqs may make a diff.Is the chappel m metal building? we play in metal buldings a lott here in west texas and crazy things will happen to older non shielded equip,makes you want to wrap tin foil round your head, I think the mfg will be able to help, hope so! Shure it was feed back or was it a recived transmission signal? that may be a clue GOD BLESS GIG ON!!!!!!

 

[agedhorse]

Induction loop systems can certainly cause interference with single coil pickups as well as other high impedance devices. Even humbuckers can pick up a loop under some conditions. These systems do not use carriers but use the direct audio passed through the loop to generate a electro-magnetic field that is based on the audio program. That's exactly why it interferes directly with the audio from the bass, it's a pretty direct form of feedback.

Extra good shielding is really the only solution, assuming you can't alter the location of the loop so that the band is not inside it.

 

[Ric5]

A p-bass pickup is not single coil. It is 2 reverse wound pickups wound in series to make a humbucker.

Maybe you need to sheild the pickup cavity and the wiring.

 

[TimmyP]

A p-bass pickup is not single coil. It is 2 reverse wound pickups wound in series to make a humbucker.

Maybe you need to sheild the pickup cavity and the wiring.

They are supposed to be Perhaps the OPs are not. It's certainly odd that the P would pick up the loop but the single coil J would not. (I once had a player who's Jazz was picking up buzz from something in the venue. His Mustang - which has a cheap P-type setup - was dead quiet.)

 

[agedhorse]

Even a hum-bucking pickup can pick up broad band AF EMI. The typical humbucker is a pretty crude affair and while it may be quie effective with the long waveforms like 50/60Hz, at 1kHz, the wave becomes shorter and the rejection capabilities will decrease. That's why a combination of shielding (better at high frequencies) and humbucking coils (better at low frequency) give the best overall noise rejection.

It's also possible that the pickups or switching are not wired as expected, or there is a defect in the pickup itself, or the shielding is compromised.