Erratic Distortion "HELP""HELP"

Allen Howington · From: North Carolina, USA

Equipment used: Emmons LGII or Justice (both D-10, Evans SE-200 15"spk, Memory Man effects unit (use send/return jacks), Peterson Flip tuner, Telonics volume pedal, standard pickups (single coil on Emmons/705's on Justice Humbucking). "Sometimes" I get a lot of distortion during playtime with the band on stage. I have unplugged, removed some effects, changed cables, etc that I can think of. So in saying all of that, here is my question; When playing on stage you never know how much is on these 120VAC circuits, I know its lower power compared to 240VAC (120VAC: 20amp/#12 wire & 15 amp/#14 wire), but I have about six plug in's myself. I realize a lot of the "stuff" is only ma (milli-amps), but when you add everything up it begins to really get higher than you think. The PA and monitor system are also on 120VAC circuits as well. The bass player, the guitar player and all of his "little toys". Is it possible that I could be on the far end of the circuit and that the voltage drop is enough to distort the Evans amp (or any amp for that matter)? Thanks for any input as this is an on going problem. If this could be the problem, what is a recommended fix for this? I don't think I would want to haul around a power transformer, but who knows, maybe that would be a fix------HELP!

Georg Sørtun · From: Mandal, Agder, Norway

It is possible that the mains voltage drops too low or become too noisy in periods for the power-supplies in one or more of your units and/or your amp, and thereby introduces instability-noise across the units' internal voltage regulator circuits. Don't know much about the units/amp you use, so cannot say which ones that are most suspect to distort with low voltage.

From years of experience, having worked as an electro engineer (high power), and from building and running recording and radio studio equipment, low and/or unstable mains voltage is something I have had to deal with all too often - and that is mainly with equipment running on the 230-240 Volt mains we use in Norway.
What little experience I have with running electronic equipment on 115-120 Volt in the US, tells me that whatever problems I have had in Norway, are nothing compared to what can happen when connecting something to your lower-voltage mains. Half-the-Voltage = twice-the-Amperes for the same power (Watt) drawn, and not all cabling I've seen seems to reflect that and the mains fuses used.

Anyway, when I really want/need stable mains voltage, I use a Constant-voltage transformer, and such units tend to be heavy if real power is needed - my old go-to "saturation transformer" for 900 Watt at 230 Volt/50Hz weighs about 8kg (around 18lbs). Have no idea what an equivalent "saturation transformer" for 120 Volt/60Hz will weigh.

If it is only your effect units that start to distort with low mains voltage, then a much smaller and lighter such "saturation transformer" will easily do the job for those, and there are other small, low-weight, "electronic mains regulators" that can fix the problem with too low, unstable and/or noisy mains supply for less power-hungry units.

Jack Stoner · From: Kansas City, MO

One comment, you are not on the "end". If your AC voltage is low, everyone on the same AC circuit's voltage is low.

Dick Sexton · From: Greenville, Ohio

Hello Allen, hope you fellows in the NC are enjoying the nice weather. Snowed here last night...

More then one steel/same amp... could be power or anything else in the chain.

More then one amp/same steel... Could be power or anything else in the chain.

Your using the best you can buy, so it becomes a process of elimination.

I am using a Strobo-flip tuner also, it puts distortion or tone suck in the sound. I never leave it plugged in and even then I have to adjust my amp for the 36" tuner cord to my volume pedal. I do have 1 Meg isolation resistor in my volume pedal, no matter, I can hear it.

Low Input Power? At lower volume, usually not a problem. At higher volume, can very well be a problem. Get a long extension cord, long enough that you can plug into a circuit not used by guitar, bass or pa(or anything else if possible).

Just a few thoughts...

Craig Baker · From: Eatonton, Georgia, USA - R.I.P.

Allen,
The problem you describe may be happening if the filter caps in your amp are getting weak or were not chosen properly to be of large enough value for the job. This can allow the voltage to "sag" as more current is drawn. It would show up more when playing loud on C6th and be less noticeable with lower passages on the upper E9th neck.

I've seen an amp's pilot lamp get dim as the C6th chords became louder.

Craig
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Georg Sørtun · From: Mandal, Agder, Norway

Since not all audio-effect units are equally well stabilised and sensitive to low or unstable voltage, where one is along the mains doesn't necessarily matter much when it comes to who's units distort. Some units can hardly handle -10% voltage drop, while others can handle -25%. Can only be determined through tests and elimination, which means you need access to some means for varying and measuring the mains voltage while running the equipment.

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