Keyboards and Generators

[StanC]

Never heard this before but as we were discussing the venue for an upcoming gig, the possibility of a need to use a generator was discussed. One of my band mates said that without a power conditioner, a generator eats keyboards. He knew of one player who lost two boards while running on power from a generator without the conditioner. No mention was made of all the other electronics.

 

Any electrical/electronics experts out there? Is this a fact and if so to what extent? i.e. are all electronics at risk or maybe just those with computers like keyboards?

[nickd]

I don't have the technical knowledge about generators that others can chime in with, but in my experience it can be a problem. Not all generators are the same in the quality of the AC mains they push out...

 

I use a voltage regulator now for outdoor gigs or ones where I'm suspicious of the power - like this one:

http://www.amazon.com/dp/B00009RA60

(and the comments on that Amazon page may be helpful).

 

[StanC]

I use a voltage regulator now for outdoor gigs or ones where I'm suspicious of the power - like this one:

http://www.amazon.com/dp/B00009RA60

(and the comments on that Amazon page may be helpful).

What's the back panel look like? i.e. how many devices can be connected? Is it possible or does it even make sense to attach a(redundant)surge suppressor/power strip to accept the five lines required to run my rig?

[nickd]

I use a voltage regulator now for outdoor gigs or ones where I'm suspicious of the power - like this one:

http://www.amazon.com/dp/B00009RA60

(and the comments on that Amazon page may be helpful).

What's the back panel look like? i.e. how many devices can be connected? Is it possible or does it even make sense to attach a(redundant)surge suppressor/power strip to accept the five lines required to run my rig?

 

I can't remember exactly and don't have it here to check, but you get multiple IEC outlets, and yes you can then attach another power strip to give you the five lines you need (if they're not all 3-pin IECs).

[Joe Muscara]

This has been discussed here before. Some posters mentioned running a Hammond and the voltage drops were a problem!

 

Remember, most modern keyboards are basically computers, and the quality of power is critical.

[The Real MC]

I remember a gig where a bad extension cord caused a brownout dropping the AC to around 90VAC. The mixer mostly worked, the Andromeda didn't. But my (vintage) Hammond Porta-B, Leslie 760, Moog Synamp, and Voyager kept right on rolling. The Voyager was important because I was using that for LH bass!

[Emeritus]

I have never run a keyboard using a generator, but I have used generators during many amateur radio emergency Field Day exercises. In recent years we have had good success using Honda EU series generators that feature clean inverter technology--the output waveform is very much a sine wave. The generators are extremely quiet, efficient and do not generate RFI hash.

[MoodyBluesKeys]

There is no quick easy answer. Portable electric generators vary very much in capability. The most common cause of problems is sudden considerable changes in voltage output caused by variations on the total load placed on the generator. Most smaller portable generators use a system of motor control where the motor is given more fuel when a drop in rpm is sensed (the drop due to heavier loading on the electrical generator) - this is a mechanical system that does not respond instantly.

 

There are two areas (IF nothing but the band is being powered by the generator) which will create most of the sudden variations in load - lighting and the power amplifiers. Lighting being switched on and off or varied causes wide variations in load. A single power amplifier may suddenly vary from drawing 50 watts to 1000 watts due to a drum hit, bass hit, etc.

 

It is worse if other things at the venue are also being run from the generator (refrigerators, any varying heavy load).

 

Best way of keeping these things to a minimum is to use a generator that is capable of producing several times the maximum load (if maximum load is 5,000 watts - generator capable of 20,000 watts). This does get expensive even for rental, and uses more fuel - but it is the best protection.

 

Surge protectors are a little help, but they don't cover the problem where a device that is a computer, such as most modern keyboards, gets lower voltage down to a point that the system reboots or gets wonky. UPS devices can be of some help here, but they are also not inexpensive, and there is some loss of power.

 

Another consideration is the noise produces by the generator(s). Needs to be far enough away not to be a problem in the venue, and that gives yet another potential problem - large enough connecting cords to avoid voltage drop at full current.

 

A possible approach would be to use one or more large standard generators to run power amplifiers, lighting, and such things, and then one or more Honda inverter style generators (which are limited in total power, but do provide good regulation and a proper sine wave output as long as not overloaded - however, they are expensive) to run sensitive equipment such as keyboards and many mixers, sound effects devices. etc.

 

Professionals who set up equipment for high-profile tours and that sort of thing usually use very large generator equipment, located far enough away so the sound produced by the generator is not a problem.

 

[StanC]

Thanks for the replies and information! Certainly good info to know for the future. But a surprise solution has come up! The venue for this gig is a Town sponsored outdoor concert in the newly constructed pavilion adjacent to the town hall. Our trumpet player, who is also our lighting technician; who is also an ex-contractor; who is now a Town building official, has convinced the first selectman that not running electrical service to the pavilion was a mistake. So as I type, the pavilion is being wired for 100 amp service. Potential problem solved!

[OB Dave]

Good to hear they wired the pavilion.

 

BTW, the problem with Hammond organs is not voltage, it's frequency. The Hammond's synchronous motor uses the 60 Hz line reference as an internal frequency reference so this has to be spot-on. Voltage fluctuations aren't as much of an issue. Trek II makes a quartz crystal 60 Hz reference box that makes a tonewheel Hammond impervious to line frequency problems.

[CEB]

Most of our sound guys bring a tap kit and if they have to they will provide us with our own electrical service. Unless we are truly in the middle of BFE.

 

You do what you have to do I guess. But I would really not want to run digital gear off a honda generator. A regualted battery backup UPS thingy for your keys might be a good investment.

[Threadslayer]

 

BTW, the problem with Hammond organs is not voltage, it's frequency. The Hammond's synchronous motor uses the 60 Hz line reference as an internal frequency reference so this has to be spot-on.

You took the words right out of my mouth. Hammond's hate generators. It sounds so bad it will give you audio vertigo.

[Joe Muscara]

But I would really not want to run digital gear off a honda generator.

Why not?

 

 

BTW, the problem with Hammond organs is not voltage, it's frequency. The Hammond's synchronous motor uses the 60 Hz line reference as an internal frequency reference so this has to be spot-on.

You took the words right out of my mouth. Hammond's hate generators. It sounds so bad it will give you audio vertigo.

My bad. I misremembered.

[theGman]

@ Stan C: I have that same unit, APC LE 1200; it has 4 outlets on the back. Regular 3 prong outlets. Hope that helps.

 

Paul

[J. Dan]

I've had good experience with the large "trailer" style generators that have been provided to the outdoor concerts I've done. Never paid attention to the brand.

 

I've only had problems when they DON'T use a generator and instead try to run power from far away through inadequate extension cords.

[bdodds]

I remember trucking my A-100 out to a gig that was running a generator and was putting out somewhere like 57-58 cycles. I had to transpose my set a half step up and it would occasionally drift flat from there even. Bad times.

[B3bluesman59]

Over the years I have had a problem with outdoor venue generators. When the voltage varies my keyboards would shift pitch....usually going flat. It happened one time about a year ago with my PX3 and another time years ago with a Korg M1. I told the stAGE crew running the generator and they would not belive there was a problem until the guitar amps starting acting strange also.

[JimboKeys]

The other thing to watch out for is that you don't want to have your equipment on during startup and shutdown of the generator. I've experienced too often the situation where the idiot running the generator thinks his job is to save gas by turning off the generator as soon as you've played your last note. Make it real clear to the folks running the show that the generator is not to be shut down until you give them the all clear.

 

- Jimbo

[WesG]

Mild voltage drop is not a problem with a Hammond - FREQUENCY is the problem. If your generator can't do a steady 60.000Hz, you will be out of tune.

 

GOOD generators come on trailers and have gauges on the back indicating line voltage and frequency.

 

BAD generators come from your buddy's garage. They drop the frequency and voltage when overloaded.

 

I would not run a rig I really cared about through a BAD generator.

 

My DGX 620 has an external "brick" power suppy that is old-school with a transformer in it. A linear power supply like that will be okay if the DC is regulated after the transformer secondaries. The new lightweight SMPS supplies are more likely to have trouble -- I usually use an SMPS with that board but would definitely grab the OEM one if I was stuck on a bad generator. Assuming there was no other option. Usually there are options.

 

Steve Leigh (Pro-Keys) used to use a crystal oscillator to generate a 60Hz sine wave, then amplify this through a Crown DC-300 amplifier which has a linear power supply. The output of the amplifier would then be turned up until the 60Hz signal was swinging 110VAC. That is a bullet-proof way of running a Hammond. And the DC-300 must be a monster amp!

 

Wes

[J. Dan]

Steve Leigh (Pro-Keys) used to use a crystal oscillator to generate a 60Hz sine wave, then amplify this through a Crown DC-300 amplifier which has a linear power supply. The output of the amplifier would then be turned up until the 60Hz signal was swinging 110VAC. That is a bullet-proof way of running a Hammond. And the DC-300 must be a monster amp!

 

Wow. The DC-300 must be a pretty bullet proof amp to be able to handle such a highly inductive load! I could see a mild resistive load, but motors?

[StanC]

I don't have the technical knowledge about generators that others can chime in with, but in my experience it can be a problem. Not all generators are the same in the quality of the AC mains they push out...

 

I use a voltage regulator now for outdoor gigs or ones where I'm suspicious of the power - like this one:

http://www.amazon.com/dp/B00009RA60

(and the comments on that Amazon page may be helpful).

 

What's the difference or advantages between the regulator and a power conditioner ?

[Delaware Dave]

I never leave home without this, whether the gig is indoors or outdoors. This has been in my gig bag for at least 15 years. I use it every gig, no matter where we play:

 

http://www.tripplite.com/en/products/model.cfm?txtModelID=208

 

 

[AnalogGuy1]

A regulator changes the RMS voltage only, a power conditioner also changes the phase.

 

Many regulators only downregulate. 130Vrms with spikes to 200Vp in, and a regulator will provide a steady 120Vrms out. Some better regulators upregulate voltage also, dropping current in the process so conservation of energy is preserved.

 

Power conditioners can do two things:

 

1) They can take the sometimes really bad "sinusoid" voltages that generators produce and make them look like perfect sinuoids. Generators voltage often looks more squarewave than sinuosoid because it is much more efficient to produce high-power squarewaves than sinusoids and to run motors it doesn't make a difference.

 

2) They can align the resulting sinusoids of the voltage provided by the generator with the load's sinusoid of the current it uses. It happens when the load looks inductive, like the coil in a speaker, and is wasteful in the sense that it will cause more current to flow back and forth in the power cable wasting power by resistive losses in the power cable, without providing more power to the speaker. When you see "power factor correction to 0.99" that's what they're talking about; a power factor of 1 means perfectly-aligned voltage and current waveforms.

 

In the US I have not had problems running electronics off large generators using nothing but an inexpensive downregulator for spikes. In some places in Europe and Africa, I have found power conditioners absolutely essential.

[opdigits]

In very generalized layman's terms power conditioners "clean" or filter the power (from noise), and voltage regulators provide a steady or constant voltage.

 

Some power conditioners will also provide protection from spikes and surges.

 

Some voltage regulators will include power conditioning.

[Sparky2]

I never leave for a gig without this: Tripp-Lite LCR2400 I often run the entire QSC PA as well as my keys/guitar rig and the rest of the band without an issue.

 

"Reliable transformer-based voltage correction circuits maintain 120V nominal output during voltage fluctuations between 89 and 147V. Three levels of voltage stabilization offer targeted response for over-voltages, under-voltages and severe brownouts. Prevents equipment damage and power related performance problems" "Network-grade AC surge and EMI/RFI noise suppression. Supports loads up to 2400 watts, 20A. Includes 14 AC outlets arranged in two separately filtered banks, 12 ft AC line cord and 7 diagnostic LEDs which display incoming voltage level, surge suppression and line status."

 

Mark

[J. Dan]

A few notes on different technologies used.

 

The transformaer based solution as listed above basically has a multi-tap transformer that can step the voltage up or down byna certain % if it gets outside of its limits. They also include filtering, but note that the frequency is unaffected. So while the voltage may be correct, if a generator is operating at 58 Hz, the power will still be 58Hz. That is likely to only affect something like a Hammond.

 

Power inverters typically take a DC voltage, generate a perfect 60 Hz sine wave, and step the voltage up to appropriate levels. This would be typical of the circuitry used in a UPS on backup mode.

 

Many so called power conditioners only provide surge suppression and noise filtering.

 

I've seen manufacturers interchange, or be less than specific with, their terminology. Best thing is to look at the specifications and see what it says about voltage regulation, brownout protection, filtering, surge suppression, power factor correction, etc. The fewer specifications provided, likely the less they are actually doing.

[StanC]

I never leave home without this, whether the gig is indoors or outdoors. This has been in my gig bag for at least 15 years. I use it every gig, no matter where we play:

 

http://www.tripplite.com/en/products/model.cfm?txtModelID=208

 

Just pulled the trigger on one of these. First thing I noticed in the manual is ". . . do not use with extension cord." With a seven foot cord how is it used? i.e. Are you powering the entire band from this unit? Or just your rig? Either way it seems like you would need either an extension from the source to the unit, or an extension/power bar from the unit to the gear.

[Mr. Nightime]

Many years ago I played a gig in Nome, Alaska. At the time my main board was a Korg M1.

 

We set up, and found that the power was so dirty that the M1 was freaking out. I would get highly distorted ghost after-images of the sound, making it almost unplayable.

 

We were going to be there for 8 weeks, so I went to the local cable company so there would be at least SOME TV stations. I mentioned that I was playing at the Polaris Bar, and the problem I'd run into at the club with my board.

 

The manager, at NO COST, loaned me a really strong power conditioner, one that would filter out the line noise, giving the M1 clean power.

 

Made all the difference in the world.

 

I haven't tried to see how my current boards would react to a generator. Being in a hurricane zone, I have a 6500 Watt generator. I may have to try this soon.

 

First thing I noticed in the manual is ". . . do not use with extension cord."

 

This usually means do not connect to an extension cord on the supply side. Plug directly into the power source. Sometimes extension cords, and especially power strips can affect performance of the units, preventing them from working correctly when needed.

 

That said, I have used an extension cord to plug a unit into the power source, but I made sure it was rated at as high or higher power rating as the unit.