Dean Markley Guitar Pickup - Buzz Problem

[BrentEvans]

I've had a couple of these Dean Markley acoustic soundhole pickups show up at the event I'm running over the last week, and I know they'll show up again in the next week.

They sound great... but they've got a bad case of the buzzies. It's not straight 60hz hum, but it shows up around 122 and 244 (harmonics?) and as a presence lift over about 3 octaves centered at 2.5k or so.

Has anyone successfully killed the hums and buzzes on these things? All I can find via Google is how hum free they're supposed to be.

[Bruce Weldy]

I've had a couple of these Dean Markley acoustic soundhole pickups show up at the event I'm running over the last week, and I know they'll show up again in the next week.

They sound great... but they've got a bad case of the buzzies. It's not straight 60hz hum, but it shows up around 122 and 244 (harmonics?) and as a presence lift over about 3 octaves centered at 2.5k or so.

Has anyone successfully killed the hums and buzzes on these things? All I can find via Google is how hum free they're supposed to be.

I have one that I use in my D35 for church gigs and I have the same problem. It's really strange - I can make it go away by rotating to the left. But, if I go too far it comes back.....I hope someone has an answer.

[tdogg]

noisegate?

[BrentEvans]

noisegate?

Doing that already, but it significantly alters the sustain of the guitar if the threshold is high enough to deal with it effectively. I've compromised by only using a 6db floor on the gate and a long attack... but it's still not effective.

[Greg Plouvier]

Are you running thru a DI?

[BrentEvans]

Are you running thru a DI?

Yup. As a matter of fact, we've tried three different kinds (Whirlwind EDB1, which are my "utility" DIs, Horizon IMP2, and Behringer DI-200, as well as running through a seperate submixer for effects, and line-matching transformers. We've tried everything I've got. Still got the buzzies.

[Sydney]

Has it been determined that the problem occurs with this pickup regardless of where it is or what it is plugged into ( indicative of a problem w the pickup itself )
Perhaps using copper foil to build a better shield cage.
Or use an isolation transformer.

I can make it go away by rotating to the left.

Rotating what to the left - precisely with respect to what?

Syd

[Greg Plouvier]

Get a different pickup - Fishman or Schertler contact. Maybe call DM and complain

[BrentEvans]

Has it been determined that the problem occurs with this pickup regardless of where it is or what it is plugged into ( indicative of a problem w the pickup itself )

Hard to say.. these are guest musicians. I don't believe the problems are in the hardware of pickups per se.. as in they're not damaged. Both musicians say something along the lines of "they work fine at home."

Perhaps using copper foil to build a better shield cage.

Not my instruments. I might tackle something like that on my own though, if it had the problem.

Or use an isolation transformer.

IMP2 has an transformer, as does the EDB1. As the Behringer is active, I'm sure it has one too (although I've never actually looked... i have with the IMP and EDB1). Are you referring to something different than this?

Get a different pickup - Fishman or Schertler contact. Maybe call DM and complain

If it were mine, I would. I much prefer a mic'd guitar to a pup in most cases anyway in most cases. In this case, since they're not mine, I have no dog in the fight, per se.

This may just get filed in the department of "oh well..." and I'll just be done with it. I was just hoping for something like "put such value cap and such a value resistor between pins 2 and 3 and it will go away magically!" Nothing's ever that easy.

[Sydney]

The more this is discussed the more it points to a intrinsic susceptibility to power line noise.
Your observation of the 60Hz based harmonics.
Perhaps you could recommend the owners of that pickup research foil shielding the pickup.
It's an electrically dirty world with a lot of modern noise sources and conditions that very wildly from their homes.
There is a lot of internet content on foil-shielding pickups and guitar parts suppliers carry copper foil because it's a common issue.
http://www.ethanwiner.com/dimmers.html

A good isolation transformer is not cheap so I have doubt of the efficacy of the cheaper D/I boxes to provide isolation.
A good Jensen transformer runs about $50+ but they are an industry staple in the toolbox.

Syd

[BrentEvans]

The more this is discussed the more it points to a intrinsic susceptibility to power line noise.
Your observation of the 60Hz based harmonics.
Perhaps you could recommend the owners of that pickup research foil shielding the pickup.
It's an electrically dirty world with a lot of modern noise sources and conditions that very wildly from their homes.

I'll pass it along... not sure how well it will be recieved.
Actually one of them is my assistant, and he'll probably do it if it gives him too much trouble elsewhere. The other one.. as I said, no dog in the fight.

A good isolation transformer is not cheap so I have doubt of the efficacy of the cheaper D/I boxes to provide isolation.
A good Jensen transformer runs about $50+ but they are an industry staple in the toolbox.

Are these sold in a premade passthrough box, or do I have to source and buy the transformer, then roll my own?

[Sydney]

Isolation transformers come as black boxes and part modules to wiring in panels etc.
Besides Jensen, Lundahl makes the better transformers.
Even Behringer makes a HD400 ( efficacy unknown ).
See broadcast suppliers like Markertek

When I encounter line noise I look for the orientation and proximity of noise and the cable routing vis a vis power lines.
This book gives a diagnostic checklist:
Practical Recording Techniques: The Step-by-step Approach to Professional ...
By Bruce Bartlett, Jenny Bartlett page 65

Syd

[Bruce Weldy]

I can make it go away by rotating to the left.

Rotating what to the left - precisely with respect to what?

Syd

Rotating me and the guitar.

As I move away from the monitor the buzz goes away. At about 45 degrees it's gone at 90 degrees off axis, it's back. It's really bizarre.

[Sydney]

Not so bizarre - it's inductance
If you bring your guitar closer to the monitor - does it get louder?
Do other items with permanent magnets and transformers and wall warts cause the problems as well?

Syd

[bgavin]

Is the monitor a powered type, by any chance?

A steady-state hum/buzz is not going to originate with passive speakers.
You are hearing power supply interaction, not speaker signal.