Voltage Regular in Rehearsal Room: 125v better than 115v?

[James Steele]

I was noticing some voltage sags in my rehearsal room. I'm talking about the power at the wall outlets, just to be clear. It's sometimes down to 114v or 115v. Paranoid that this was perhaps affecting the sound of my amplifier, I bought a Tripp Lite LCR 2400 voltage regulator from eBay since these are relatively inexpensive.

I did find an issue. I'm just guessing here, but when my voltage drops to 115v, it seems like the Tripp Lite "kicks in" makeup voltage, but in +10v increments, so my 115v coming into the Tripp Lite leaves the unit as 125v. Maybe it's an obvious question, but is 5v over 120 better than 5v under? And as an aside, isn't 120v really running at 117v usually?

[mikehalloran]

The USA standard is 120V +\- 5%. This means that a range of 114 - 126V is within acceptable tolerance for most devices except lighting.

Many international devices including Apple products run 100V to 250V.

[EMRR]

Yes, the tolerance is the key. You can measure outlets all over town and get different numbers, though all should be within that tolerance. Value will change with time of day and local load.

[James Steele]

The USA standard is 120V +\- 5%. This means that a range of 114 - 126V is within acceptable tolerance for most devices except lighting.

That's good to know. I played the rehearsal today with pretty much my entire guitar rig plugged into the TrippLite voltage regulator which indicated on the front panel that it was receiving low voltage the entire time. It may have been my imagination, but the amp sounded better. I measured the voltage at the wall outlet immediately after rehearsal (with all gear in the room still powered up) and it was 112.8V. The outlet on the back of the voltage regulator was showing 122.8V, so it seems that it steps it up by 10V.

I once rehearsed in a room that was part of a large rehearsal room complex. When the band was going next to us, I felt like my amp sounded different. I brought in a voltage regulator to next rehearsal and amp sounded okay. Maybe it's just a tube amp thing. I have a 1979 Marshall JMP head and I'm not sure just how tolerant they are of voltage sags. They may continue to work, but I do believe it can affect the sound of the amp.

Anyway, I now have two of these regulators. One I've been using in my studio control room for years and the other now is going to be assigned to the rehearsal room, primarily for my guitar rig. I'm thinking of getting a shallow 3-space rack for it and perhaps picking up a second unit and racking it as well so that when we start playing live I can drop one stage left and another stage right and plug into that instead of club wall power.

[mikehalloran]

Besides resistance lighting (incandescent light bulbs) being voltage dependent ('long life' bulbs are rated 125V instead of 115V), tube amplifiers may sound a little different when run through a Variac.

http://www.legendarytones.com/edward-va ... own-sound/

I have used an identical unit to one of these in theater lighting. The comment about USA voltage standard being 110V in the 1960s is correct, BTW

[James Steele]

Besides resistance lighting (incandescent light bulbs) being voltage dependent ('long life' bulbs are rated 125V instead of 115V), tube amplifiers may sound a little different when run through a Variac.

http://www.legendarytones.com/edward-va ... own-sound/

I have used an identical unit to one of these in theater lighting. The comment about USA voltage standard being 110V in the 1960s is correct, BTW

Right. Me, I don't think I like the sound of my amp when it's run that low. I think Eddie may have been using a Marshall head from the 60s, but mine was made in 1979, so not sure the statement that it was designed for 110V would still apply to my head?

[mikehalloran]

I rewired my Victorian house in 1980 and the guide that I bought at that time stated that 120V was the standard. If it said when that changed, I don't remember.

My San Jose house was built in 1878, moved to its present location in 1901 and probably electrified around 1915. I had to move some of the old gas piping in the attic out of the way. I love that house and wish that I could still live there but my handicap makes that nigh impossible.

I was going to pull the aluminum 2-wire (no grounding!) and re-do this 1960 ranch style where I live but the crawl space makes it a pain and then I became disabled. We have copper pigtails attached per code but aluminum wiring makes me nervous. Someday, I'll have to hire someone...

[Phil O]

...It may have been my imagination, but the amp sounded better...

I'm guessing it wasn't your imagination. I don't have any Marshall schematics on hand, but I'm pretty sure their old tube amps had very simple power supplies with no regulation or poor regulation (probably the case for all tube amp manufacturers). That means that not only will the filaments run at a different voltage, but B+ will be dependent on line voltage as well, changing bias points. In simple terms, it's gonna sound different.

Phil

[mhschmieder]

Yeah, I wouldn't worry about 115 vs. 125 per se, as long as the tolerance doesn't much exceed that and the fluctuation doesn't bounce between extremes frequently.

95V is a big problem. One of my bands had a gig a few years ago at one of SF's most prestigious venues, and they run their own power. Due to all the lighting etc. (which always seems to take priority over sound), there were huge sags, and the power was mostly between 90-95V throughout the gig. It fried several pieces of gear beyond repair.

Underpower usually is worse than overpower -- especially for digital gear and computers, which tends to have smaller tolerances than analog gear.

I'm really only focused on those aspects, due to having had some really bad experiences with under power, so haven't really entertained whether 115V "sounds" better than 125V.

[James Steele]

Yeah, I wouldn't worry about 115 vs. 125 per se, as long as the tolerance doesn't much exceed that and the fluctuation doesn't bounce between extremes frequently.

95V is a big problem. One of my bands had a gig a few years ago at one of SF's most prestigious venues, and they run their own power. Due to all the lighting etc. (which always seems to take priority over sound), there were huge sags, and the power was mostly between 90-95V throughout the gig. It fried several pieces of gear beyond repair.

Underpower usually is worse than overpower -- especially for digital gear and computers, which tends to have smaller tolerances than analog gear.

I'm really only focused on those aspects, due to having had some really bad experiences with under power, so haven't really entertained whether 115V "sounds" better than 125V.

In my rehearsal room the voltage has dropped as low as 112.8V. Of course, it has probably been doing that for years. Also I discovered that two of the outlets had the hot and neutral reversed, so I fixed that. Anyway, with the regulator on it, it stays at about 123-125V consistently, so I'll just continue using it. As far as old tube amps go, I'm thinking it's not unreasonable that you might hear a difference.

[HCMarkus]

The only issue to be on the lookout for with regulators like this is line-induced clicks as a the regulator (a multi-tap transformer) switches from one tap to another when supply voltage moves to different range.

[4stripes]

Underpower usually is worse than overpower -- especially for digital gear and computers, which tends to have smaller tolerances than analog gear.

I'm really only focused on those aspects, due to having had some really bad experiences with under power, so haven't really entertained whether 115V "sounds" better than 125V.

Not necessarily. Most devices these days use universal switch mode power supplies that are completely fine running from 90V to 240V. They are designed to do so.

[James Steele]

Underpower usually is worse than overpower -- especially for digital gear and computers, which tends to have smaller tolerances than analog gear.

I'm really only focused on those aspects, due to having had some really bad experiences with under power, so haven't really entertained whether 115V "sounds" better than 125V.

Not necessarily. Most devices these days use universal switch mode power supplies that are completely fine running from 90V to 240V. They are designed to do so.

Right. Key word "these days." However, I received a message from an amp tech in town who told me it shouldn't make much of a difference and if anything an amp will get "cleaner" sounding. Just so many things coming at me these days telling me I'm not hearing what I'm hearing and not to trust my own ears! LOL