Got hum out of Lucy Paulsen's Fender 400 with Peavey Mixer

Gregory Ide · From: Minnesota, USA

Hi Jack,

I answer your thread by starting a new one because this may be of wider use. I have over 50 fluorescent lights and every guitar and amp I've used at home has 60 cycle hum. (The problem is not the guitar and amps, as they all are humless when I use them at a house that has LED lighting.) By putting the guitar output into the 1/4" microphone input of a Peavey XR8300 powered mixer, the hum is eliminated. I'm not sure what circuitry the Peavey is using, but it works. Playing the instrument through the Peavey monitor speakers is clean but has limitations. It is not nearly as loud as you would expect for a 300 watt RMS system. I suspect this is because I'm using a microphone input and the output of a microphone is typically higher than that of a guitar? The Peavey mixer has a limited number of effects. "Classic Spring" and "Vocal enhancement 2 which Brightens and adds Spring reverb" are OK. The delays with repeats and slap-backs are not. The Peavey Neo Monitors are better suited for vocals than instruments, I'm guessing?

There is an output called "Main" (or Monitor) on the front panel. (not the Main and Monitor outputs in the back that are the speaker outputs) that allow me to to pull the non-humming signal off the Peavey preeamp and patch it into a modeling practice amp. That is a wierd setup that really is using two preamps, but it works. I would say it has more distortion than playing the instrument directly through the mixer, but allows me to use all the effects of the modeling amp.

As far as the POP you hear when you power up a Peavey. I think they all have it. My MKIII Bass amp (late 70s) has a deep pop, my Vegas 400 (mid 1980s?) has a high pitched pop and the XR8300 (purchased new in 2006) has a deep woof upon powering up.

The XR8300 is an impressive piece of equipment for $400. It's bigger sister XR8600 (600 watts) runs the stage at local Mpls. bar Driftwood. I'm not sure if the mains there are powered, but if not, that is a $600 system that will fill a medium size venue with sound, as well a systems 20x the cost. I use the 8300 as sound stage for fishing contests. The winners are often holding a microphone for their first time, and walk right in front of the speakers. Other systems feedback, the Peavey is pretty resistant. (I am in no way associated with Peavey, and have never been to Meridian Mississippi. )

Greg Ide

Donny Hinson · From: Glen Burnie, Md. U.S.A.

You're getting far less gain, so along with the notes and chords being reduced in volume, so is the noise. Since the noise is only generated when the lights are on, turn off all unnecessary lights when you're playing, and replace the one or two you really need with LED's or incandescents.

Gregory Ide · From: Minnesota, USA

Hi Donny,

It is pretty easy to run the modeling amp loud enough that I can hear the hum everywhere, then run around and turn off all lights. That did not help. Perhaps there is a light dimmer that is causing the problem. Or neighbors lights. Or maybe the 330,000 KV? line a block away. I live in the middle of Mpls.on the double track main line. Maybe the controller for the rail switchgear 100 feet away?

The Peavey mixer diminishes the hum. I put the Input channel at about 0.5 and the Gain at 0.5, (about what I would run the PA with spoken voice in a 1000 seat auditorium at 4 ohms) I can barely hear the hum, yet the guitar is loud, much louder than normal practice volume. It also lowers the hum of all other guitars I've tried.

I can also connect the guitar directly into the power amp of the Peavey. In that case I'm not sure if the hum is lowered, as the overall volume is quite low. I believe the power amp is always running at the given power, and I have no way to raise its volume without adding an external preamp. But the experiment where I've patched from the Peavey preamp back to the modeling amp tells me the hum lowering effect is in the Peavey preamp.

Greg Ide

Jack Hanson · From: San Luis Valley, USA

Greg,

I can't remember whether your instrument has the Jazzmaster or the Jaguar-pickup. From my research, mainly on the Fender Steel Forum, it would seem the older Jazzmaster-type pickups are notorious for transmitting 60-cycle hum.

Have you tried using a headphone amp or a battery-powered amp that's independent of your power supply?

Do you have an aquarium? An air ionizer? Electric blankets (wish I had one lately)? Old-style doorbell transformer?

There are filters available that plug in between your amp and electrical outlet. One of those may help.

Perhaps you have seen this previous thread. If not, there's plenty of good acvice therein. It may or may not be a similar situation to yours, but may provide you clues as to where to look:

http://bb.steelguitarforum.com/viewtopic.php?t=242250&highlight=cycle+hum

One other thought: Call NSP (or Xcel or whatever it is this month). They may be able offer you some suggestions and will possibly send a tech to check for outside interference.

Good luck with your 400, and with solving your hum issue as well.

Jack

Stephen Cowell · From: Round Rock, Texas, USA

I believe your hum-lowering effect has to do with loading the pickup... loading the pickup harder appears to improve the signal/noise ratio. I can see this, since there's more current behind the string than the noise, coming out of the pickup.

So I'd try a Black Box, Freeloader, Lil' Izzy, or other matching device. Carrying around a Peavey PA head for this purpose has got to be a PITA!
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