OK Weird happenin's with my rig tonight

Richard Sinkler · Post by **Richard Sinkler** » 27 Sep 2015 2:18 am

Setting onstage next to the big honkin' PA speaker. They are playing background music before we started. I was getting the songs being played, coming through my amp. Also got some screaming feed back a few times for no apparent reason (I was about 3 feet from my amp). Went from my guitar to my EQ dobro sim, to my Digitech Distortion Factory, to my Hilton volume pedal, to my amp. All George L cords. I run my RP155 through the effects loop in my Nashville 400 for reverb only. If tonight was Halloween I could understand it.

Stephen Cowell · Post by **Stephen Cowell** » 27 Sep 2015 10:13 am

Were you mic'ed or DI? If DI, how was that wired? Either the sound is coming in through the DI circuit or your guitar pickup was picking up the speaker and re-amping it... the latter would explain any feedback.

Edward Rhea · Post by **Edward Rhea** » 27 Sep 2015 10:35 am

I'm just glad to know you're playing again, Richard!
I had an old Peavey bass amp that would pick up radio frequencies...two way radio or talk stations. You could hear it was people talking, but it wasn't a completely audible conversation? It would do it even without an instrument or effects plugged into it. The amp worked perfectly other than that.

Richard Sinkler · Post by **Richard Sinkler** » 27 Sep 2015 11:42 am

Stephen Cowell wrote:Were you mic'ed or DI? If DI, how was that wired? Either the sound is coming in through the DI circuit or your guitar pickup was picking up the speaker and re-amping it... the latter would explain any feedback.

Neither. And we were playing loud, but no louder than many other gigs I play, and never had any problems with feedback. I haven't had time to check the pickup to see if it might be bad. They are 710's.

I was right next to their PA speaker. My pickups were no more than maybe 12" or less from the PA speaker. I was to the left and slightly behind speaker. It was close enough for me to use as a 'table' where I set my glasses and tuner. I didn't think that a pickup or guitar could just pick up audio. It Wasn't strings picking up the sound and possibly vibrating, as it didn't stop if I put my hand on the strings.

Richard Sinkler · Post by **Richard Sinkler** » 27 Sep 2015 11:55 am

Edward Rhea wrote:I'm just glad to know you're playing again, Richard!
I had an old Peavey bass amp that would pick up radio frequencies...two way radio or talk stations. You could hear it was people talking, but it wasn't a completely audible conversation? It would do it even without an instrument or effects plugged into it. The amp worked perfectly other than that.

The band I was in during the mid 70's hab that happen through a Shure PA, but I have never had that problem with an amp.

I forgot to mention, it was acoustically dead room (on purpose), so I needed a little more treble and less bass (also because My amp is right next to the bass amp) than normal. Turning down the treble controls lessened the volume of the sounds enough to play. I have a lot of songs to learn for a gig I am doing on the 23rd, so I will also run through all my cords to make sure the plugs are tight. I have a gig or two this coming weekend. That will show me if this is going to be an ongoing problem.

Craig Baker · Post by **Craig Baker** » 27 Sep 2015 12:45 pm

Richard,
In the situation you describe, with such close proximity your pickup might have been inductively coupled to the voice coil of the speaker. If the voice coil had 20 turns and your pickup had 1000 turns, you have what amounts to a 50-to-1 step-up audio transformer which would provide gain.

Some may remember, one year at St. Louis Jerry Byrd was in Hawaii but was going to address the convention via a telephone hook-up. When the wired connection failed, we held the telephone receiver's earpiece over a convenient steel guitar on stage. (Don't remember which artist's guitar it was.) The sound crew turned the steel up and everyone in the auditorium heard Jerry's greeting clearly. (We covered the mouthpiece with a hand to avoid feedback) Try it with your home phone. . . it works.

I'm guessing yours was a case in inductive coupling, just as we used for Jerry Byrd's phone call.

Best regards,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024

Peter Harris · Post by **Peter Harris** » 28 Sep 2015 1:25 am

Hmm...

"a case in inductive coupling"

....sounds like the initiation to an interesting club !!

Craig Baker · Post by **Craig Baker** » 28 Sep 2015 3:16 am

Hi Peter,
You were initiated to an interesting club when you bought a steel guitar!

Best regards,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024

Tim Marcus · Post by **Tim Marcus** » 28 Sep 2015 7:29 am

was there an inductive loop hearing assistance system installed? I have had that exact same problem with them before when playing in churches. Its an ADA requirement to provide listening assistance now in CA.

Richard Sinkler · Post by **Richard Sinkler** » 28 Sep 2015 10:27 am

Tim Marcus wrote:was there an inductive loop hearing assistance system installed? I have had that exact same problem with them before when playing in churches. Its an ADA requirement to provide listening assistance now in CA.

That's interesting stuff. I'd never heard of it. I looked up and read the ADA requirements. Although I doubt this club has them. It's a pretty small place, and probably couldn't easily afford them. Although, any business in Jack London Square is probably well off as far as finances. I'm not sure if they have to post signs so the hearing impaired will know that that technology is present in there establishment.

Would this technology cause the same problems in other amplifiers, PA system on stage?

And, and music is usually so loud, anyone with a hearing problem would be able to hear anyway.

And I forgot to mention. The problem would go away if I turned the amp off.

Ian Sutton · Post by **Ian Sutton** » 28 Sep 2015 11:43 am

I think I did battle with that stage a couple weeks ago. Though I didn't encounter that specific issue...I recall the sound guy not really being aware of what a ground lift is or does.

Craig Baker · Post by **Craig Baker** » 28 Sep 2015 12:23 pm

Richard,
The only time the problem is likely to occur is if you have a high impedance inductive device feeding your system. A low impedance device would not be affected, nor would a Piezo device like the old Barcus-Berry pickups.

Best regards,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024

chris ivey · Post by **chris ivey** » 28 Sep 2015 12:36 pm

maybe a li'l izzy would have solved
the problem!

Craig Baker · Post by **Craig Baker** » 28 Sep 2015 1:29 pm

I don't think so Chris, Li'l Izzy doesn't perform miracles. If "outside" music, hum or noise, radio signals, light dimmers etc. are getting into the pickup, Li'l Izzy will just see it as signal from the pickup and treat it as such.

However. . . I will have to admit, the "outside" music, hum or noise, radio signals, light dimmers etc. will all sound better and have more string separation.

Best regards,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024

Richard Sinkler · Post by **Richard Sinkler** » 28 Sep 2015 1:56 pm

Craig Baker wrote:Richard,
The only time the problem is likely to occur is if you have a high impedance inductive device feeding your system. A low impedance device would not be affected, nor would a Piezo device like the old Barcus-Berry pickups.

Best regards,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024

What would something like that be?

Craig Baker · Post by **Craig Baker** » 28 Sep 2015 3:20 pm

Richard,
Your guitar's pickup is the obvious culprit in this case. It is high impedance and since it consists of a coil, it is also inductive. I assume you're using a single coil pickup. A hum-bucking pickup might ease the pain. (might)

Best regards,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024

Richard Sinkler · Post by **Richard Sinkler** » 28 Sep 2015 3:29 pm

Nope. I use Bill Lawrence 710's. Tomorrow when I take my stuff out of my garage, I'm going to check the pickup to see if it might be microphonic. Don't know if that will tell anything, other than possibly a bad pickup. Does the Hilton pedal have a buffer in it? I'm probably dreaming this, but I thought I read somewhere that it changes the signal to low impedance.

Craig Baker · Post by **Craig Baker** » 28 Sep 2015 4:01 pm

Yes, I'm pretty sure the Hilton pedal contains a buffer, but as I mentioned earlier that will not remove any part of the pickup's output. If you play there again, see if the background music comes through with the pedal off. If it still comes through, then the pickup is not the problem, instead, the music is getting into your signal chain another way, down stream of the pedal.

Best regards,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024

Richard Sinkler · Post by **Richard Sinkler** » 28 Sep 2015 6:46 pm

I have my Hilton so there is a little signal in the off position.

Ian Worley · Post by **Ian Worley** » 29 Sep 2015 11:36 am

Craig Baker wrote:Some may remember, one year at St. Louis Jerry Byrd was in Hawaii but was going to address the convention via a telephone hook-up. When the wired connection failed, we held the telephone receiver's earpiece over a convenient steel guitar on stage. (Don't remember which artist's guitar it was.) The sound crew turned the steel up and everyone in the auditorium heard Jerry's greeting clearly.

I do this all the time at band practice. I have recordings of the songs in my phone, I just set the phone on the strings over the pickup and everybody can hear it loud and clear (with VP control!)

Glad to hear that your back from retirement and playing out again Richard!

Michael Brebes · Post by **Michael Brebes** » 29 Sep 2015 1:28 pm

I've had that happen before. Because of the large magnets on some of those speakers, coupled with the large wattage being fed to the speaker, it creates this huge magnetic field that is feeding the PA input directly into your pickup. Look at the size and power of magnets on a speaker compared to those on a pickup. It's no contest, the speaker will win every time. It doesn't matter how good or bad your pickup is, the speaker will win.

Richard Sinkler · Post by **Richard Sinkler** » 29 Sep 2015 1:49 pm

That was probably it, Michael.

Keith Hilton · Post by **Keith Hilton** » 29 Sep 2015 1:51 pm

Interesting. What Michael Brebes is saying sounds logical. On the input of the circuit of the Hilton Pedal I protect against radio frequency signals. I do this with a 39pf capacitor to ground. The 39pf capacitor feeds all radio frequency signals to ground and will not let them pass through the circuit of the pedal. In the last 18 years of building these pedals I have not had a single problem with radio frequency signals passing through the circuit of the pedal. What Michael Brebes is describing, is a magnetic field that is creating induction through your guitar pickup. The signal your pickup is putting out through induction is not radio frequency, or it would not pass through the pedal. Your pickup is putting out a signal in the audio frequency range.

Alan W. Black · Post by **Alan W. Black** » 4 Oct 2015 7:07 pm

Magnetic field is an interesting answer. You were pretty close. It could also easily be acoustic if the PA is loud enough. You can shout into a guitar pickup at very close range, and some one sitting beside your loud amp on the other side of the room can hear it. I think the vibrations are enough to wiggle your pickup a little, but dental work aside, you would not be introducing a magnetic field.

Steve Allison · Post by **Steve Allison** » 2 Nov 2015 7:14 pm

Yep what Craig Baker said! Hold a Telecaster up to your face and shout into the pickup with the amp turned up. Not near as strong as a microphone but you will for sure hear that shout through the amp speaker!