Why does an amp change it's sound?

George Kimery · Post by **George Kimery** » 23 May 2007 7:06 am

I was up until 1:30 am last night trying to figure out why the magnificent sound on my Steel King had changed. I tried setting the amp different, moving it around in the room, tweaking the knobs, changing cords, eliminating the Hilton Pedal, etc. and finally, replaced all the strings, even though the set I had on was only 2 weeks old. Nothing worked. It still sounded like an ordinary amp, not the Steel King sound. This morning, I got up and tried it again and the sound was back the way it should be. I have had this happen on other amps on rare occasions too, so I don't think it is a Steel King problem. The only theory I have is that it is a voltage drop in the AC power coming into the house. It is an old house with only 2 prong wiring, also. I am going to check the voltage while it is performing normal then if I ever have the problem again, I will check the voltage then. This is about the only clue that I have as to why an amp can change its sound when it hasn't been moved or the controls have not been tampered with. Has anybody else had this problem, on rare occassions? Humidity affecting the speaker, etc? What is the answer?

Erv Niehaus · Post by **Erv Niehaus** » 23 May 2007 7:10 am

I think you may be onto it with the voltage issue.

I recently added a fairly expensive power conditioner to my rack. It has a voltage meter on it and it's quite interesting to note the difference in voltage between different places.

Kevin Hatton · Post by **Kevin Hatton** » 23 May 2007 7:48 am

Sounds like voltage. It happens to me here.

Jack Stoner · Post by **Jack Stoner** » 23 May 2007 8:20 am

Your own "hearing" can change. I've played the same place with the same amp settings/effects/guitar and think it "sounds different" when the rest of the band tells me "it sounds the same".

But, AC voltage can change the sound.

John Daugherty · Post by **John Daugherty** » 23 May 2007 9:14 am

George, Jack brought up a good subject. I have been in the same boat when I listened to the same sound for a long time(without much sleep). It could very well be the "brain connected to the ears" syndrome or a plug of earwax. Attitude can change due to various factors such as too much time in the studio. This can actually cause you to hear things differently.
I have also experienced a "flat" sound due to a bad cable. A cable can have one little whisker of a wire, shorting across inside the plug. The cable will still work, but cause a loss of "brilliance".

Brad Sarno · Post by **Brad Sarno** » 23 May 2007 10:48 am

What Jack says is very true. It's no subtle matter either. It's amazing how the ears' perception changes thru the day. Being tired, awake, fed, hungry, caffeine or no caffeine, etc. The perceived change can be enormous.

Brad

Kevin Hatton · Post by **Kevin Hatton** » 23 May 2007 11:10 am

I'll agree with that also. Hearing does change.

Mike Wheeler · Post by **Mike Wheeler** » 23 May 2007 12:32 pm

Humidity and temperature also have a very noticeable effect on sound. We don't always notice it, but as humidity goes up, high frequency damping occurs. Rising temperature has the same effect, but to a slightly lesser degree.

Ever notice that in a hot, sweaty bar the sound gets real muddy?

Brad Sarno · Post by **Brad Sarno** » 23 May 2007 1:40 pm

Yup, humidity is another factor. I find that speakers sound radically different in the humid summer months compared to the dry winter months.

Brad

Bill Terry · Post by **Bill Terry** » 23 May 2007 2:14 pm

One band I play with is pretty loud, and I usually go through 3 phases as far as ears on just about every gig with those guys.. First half of first set, everything sounds too bright, by the end of the set things are more or less 'normal' sounding and still good for the next hour or so, by the end of the last set I'm cranking on the treble knobs trying get some clarity and manage to cut through the 'mud'.

On the other hand, when I do a gig with some of the more 'moderate' volume bands around town it doesn't seem to be near as much of a problem. It's more like phase 1 and phase 2, without the treble cranking in phase 3.

I attribute the '3-phase' syndrome above to my ears trying to protect themselves by 'shutting down'. I read somewhere about this phenomenon and it was called 'temporary threshold shift' or something like that, and if it happens a lot, it becomes permanent threshold shift, or essentially hearing loss.

Oops topic drift... sorry.

James Marlowe · Post by **James Marlowe** » 23 May 2007 2:44 pm

I've run into a similar situation at church.
I was set up on the same end of the platform with the "overbearing" six stringer. My amps were behind me and the sound was pretty decent. (what I could hear of it!)
I switched ends on the platform. Now I'm more crowded with my amps beside me and against a wall. I can't get a good sound for the life of me. Sounds like pure mud! It may sound okay to others, but to me it stinks!
jrm

John Jeffries · Post by **John Jeffries** » 23 May 2007 5:44 pm

A build-up of wax in the ears can have a significant effect on what you hear, in terms of both volume and tone, and to some extent, clarity as well! I regularly (every couple of months) use a rubber ear pump with warm water to pump out excess wax build-up from my ears. This is usually the first thing I do, if I notice a difference in volume, tone or clarity when playing, either at home or on stage!

Donny Hinson · Post by **Donny Hinson** » 24 May 2007 12:58 am

You can probably forget the line-voltage thing. Line voltage usually effects headroom only, not the tone. In addition, line voltage would be at it's best at 1:30 in the morning, when the commercial load on the power grid is about zilch.

Mostly, this "tone variation" thing is a case of perceived tone. The tone doesn't really change, but your ears and the surroundings do. At any rate, on those occasions when you simply can'y get a good sound, it's sorta like when you can't seem to get in tune. The more you go "adjusting" things - the worse things seem to get. When you reach that point, you have two options...just get up and walk away, or forget it and go on playing.

I'd suggest the latter over the former.

Randy Reeves · Post by **Randy Reeves** » 24 May 2007 4:20 am

just as tone is in the fingers (somedays are better than others)
amp is in the ears.
I believe this.
I also believe there are other factors such as, humidity, atmospheric pressure, room ambience,and
equipment changing (strings, add ons with batteries losing power).
one is not crazy.

Charlie Tryon · Post by **Charlie Tryon** » 24 May 2007 4:29 am

Well I used to go through this a lot when I first started playing the steel. I would play the first set turning knobs trying to find that sound and by the end of the second set I would have it. Well yes the sound was back but also all my settings were the same as normal. Now when I setup I make sure things are where they are supposed to be and just play, and sometimes the first couple of tunes do not sound just right but after a few more tune things start to settle in and I'm good for the night.

Charlie

George Kimery · Post by **George Kimery** » 24 May 2007 5:19 am

One thing that I didn't mention, not only was the amp not sounding the way it always has before, my RV-3 was acting up also. It had a distortion "tail" immediately after hitting a note. It was hooked up to the AC via a wall wart. I figured the RV-3 was toast and I would have to replace it. The next morning, when the amp was working right, so was the RV-3. The RV-3 problem could not have been caused by a change in my ears. I still think something was going on in the AC department. The change in sound was just too dramatic to be caused by a change in the way I hear, in my opinion. I have checked the voltage several times since and it is around 121 volts. It varys slightly from time to time. I now am carrying a voltage meter in my pack-a-seat. If I ever have the problem again, I will check the AC voltage. Thanks for everybody's input on this issue and if I ever find a correlation between poor amp performance and the voltage issue, I will post it.

David Collins · Post by **David Collins** » 25 May 2007 3:37 am

Donny Hinson wrote:You can probably forget the line-voltage thing. Line voltage usually effects headroom only, not the tone. In addition, line voltage would be at it's best at 1:30 in the morning, when the commercial load on the power grid is about zilch.

Donny, the only portion of your statement that I would disagree with is that in a lot of locations, the power companies actually scale voltage back, some as much as 10%, late at night. They do this precisely because nearly all of the commercial load is off the grid as you indicated. It is an energy savings for them.

I can not say with certainty that the power in every area is done this way, but I can say for sure that it is in My area.

Mike Wheeler · Post by **Mike Wheeler** » 25 May 2007 3:56 am

If line voltage is suspect, which it very well could be, just hook up a volt meter and leave it hooked up during the gig where you can monitor it. Even though it's correct before the gig, once everyone is cranking away, it could be sagging, and thus, causing problems. (an analog meter is best for this)

I used to do this all the time at gigs. You'd be amazed to see how much fluctuation there can be in the line voltage during a gig. Doing this doesn't solve any problems, but at least you'll identify a possible source of problems.

John Billings · Post by **John Billings** » 25 May 2007 8:11 am

I played a gig years ago, out in the styx. My 56 Pro sounded terrible! Next night I brought my VOM and measured the 'lectric. 87 VAC!

Lavelle Pierce · Post by **Lavelle Pierce** » 30 May 2007 10:12 am

I PLAYED A STREET DANCE ABOUT A COUPLE WEEKS MAN THAT STEEL SOUND GOOD. THEN AFTER DARK I NOTICED MY STEEL SOUND SOMETHING WRONG. I PUT MY PETERSON TUNER ON AND EVERY THING WAS IN TUNE. SO THE NEXT DAY I PHONED MY TEACHER AND TOLD HIM WHAT I HEARD ABOUT THE SOUND HE LAUGHED AND SAID IF YOU GE A LITTLE DUW OR DAMP WILL CHANGE SOUND. SO THAT IS MY STORY. THANKS

Post by **Dave Mudgett** » 30 May 2007 11:04 am

Even in a laboratory environment - same guitar, effects, and amp in exactly the same location - from one day to the next, I had difficulty getting a really consistent sound until I got this: http://www.furmansound.com/product.php?id=AR-1215

I have not found that line voltage variations just affect distortion level - especially on a tube amp, it affects the bias and plate voltages which can make a significant change in sound character, to me at least.

I'm guessing that RMS fluctuations in steady-state AC voltage around here, even in home service, are several volts, and it's worse at gigs, for me at least. I have measured down into the 90's VAC range a number of times, especially on outdoor gigs. I find the Furman mandatory at gigs like this.

I agree that lots of other things can affect perceived sound, including the room or outdoor physical acoustics (which can be affected by things like humidity), changes in the amp, changes in the guitar, changes in the way one plays, or psychoacoustical effects. I think alcohol or anything else that affects the mind can make a big difference in perceptions. I think it's a good idea to try to figure out what's really going on before just throwing money at it.

The Furman unit has gotten pretty pricey since I got mine - the typical Musicians Friend or zzounds.com price is $200 more than when I got mine several years back. It seems like somebody must be willing to sell these at a better discount than 10% off the $612 MSRP.

Erv Niehaus · Post by **Erv Niehaus** » 30 May 2007 11:15 am

Dave,
That's the same unit I have in my rack. I looked around for the best price and found a dealer on e-bay who was offering them at a substantially lower price than the online music outlets.

T. C. Furlong · Post by **T. C. Furlong** » 30 May 2007 11:19 am

Humidity or very dry air can make a huge change in the sound but only if there is a significant distance involved. High frequencies travel much more easily in humid air than in dry air. I would therefore say that it is line voltage sag along with ear fatigue.

I would also like to note that I have experienced gradual permanent changes in the sound of electronics. If component values drift with age or heat, the sound will definitely change and in my experience, usually for the worse. That's my main beef with inexpensive equipment. It can change greatly over time. I once worked sixty four identical shows in eight weeks (eight per week). I bought a brand new amplifier for the run (it was a Broadway show). The amp sounded terrific for the first few weeks. It sounded fair for the next few weeks and by the end of the run...not-so-good-at-all. I always attributed that to cheap parts and component drift. I know wine is probably not a good comparison but great wine gets way better with age and cheap wine gets way worse.
TC

Tony Dingus · Post by **Tony Dingus** » 30 May 2007 11:55 am

George if this happens again,unhook the RV 3. I had problems with mine the other day and it was the walwart which was a generic brand, I replaced with a boss power supply and that took care of the problem.

Tony

Mike Wheeler · Post by **Mike Wheeler** » 30 May 2007 6:55 pm

The humidity, moisture suspended in the air, doesn't have the greatest impact on sound, in general. Where humidity does have a profound effect is on paper cone speakers that will absorb this moisture, causing high frequency attenuation...very dull, lifeless sound...for players who don't use horns in their setups...like us.

And cranking the treble control doesn't correct for it.

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