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#44084 - 12/20/04 08:29 AM Requesting info for running keyboards and amps on Inverter in motorhome
BEBOP Offline
Senior Member

Registered: 01/02/00
Posts: 3770
Loc: San Jose, California
Here is a question for those in the know?
I have been told that only an inverter that provides modified sine wave will work with these new sophisticated Arranger keyboards.
The older workstations would work ok with square wave.
Please comment on this if you have accurate imputes and thanks,
I have deepcycle batteries in the motorhome and will be making a 6000 mile plus trip to florida from San Jose in the motorhome this spring for the Synthzone Jam there. I would like to use the onboard power at times in the evenings rather then run that big 7.5K Generator just to operate a keyboard.
I also have been known to start Street Dances in the Rv parks in the evenings and weekends, but they usually have power to spare, but sometimes I am not in an RV park. I am alongs side of a beautiful lake or river along with several other dry campers.
What say you??
Thanks,
Bebop
Thanks,
Bebop
_________________________
BEBOP

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#44085 - 12/20/04 09:21 AM Re: Requesting info for running keyboards and amps on Inverter in motorhome
Chuck Piper Offline
Member

Registered: 01/17/02
Posts: 403
Loc: United Kingdom
Hi Bill,

I've been out of the electronics business for many, many years but I'll try to offer you information that is factual.

I've never known of an inverter that produces anything other than a sine wave. I've never heard of the term "modified sine wave". It is not a common term for sure. Special circuitry would be required to modify a sine wave. The resultant wave could be square, trapezoidal, or a linear "ramp", or some variation of those waveforms.

Look at your manual for the inverter. It should give details of the output. The output should be 115 Vac, 60 Hz. It may also give warnings that the inverter should not be used to power certain appliances and the types of appliances should be listed.

My main concern would be "noise" in the output of the inverter. Of course I have no idea what type of noise filtering has been incorporated in the inverter circuitry. I suspect noise would be minimal because you would likely use the output of the inverter to power the on-board stereo system when you are operating self-contained.

In short, I would expect the output of the inverter to be a pure sine wave at a frequency of 60 Hz. The output voltage
would be 115 Vac. And, noise would be filtered to an acceptable level.

Finally, your inverter would be powered by your batteries. The KN7000 draws 75 watts of power. Your RV manuals should tell you how much power can be delivered by your batteries continuously and for how long.

I don't see a problem using your KN7000 or your KN2600.

Hope this helps. Maybe others can add to what I have said.

Best Wishes,

Chuck

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#44086 - 12/20/04 11:53 AM Re: Requesting info for running keyboards and amps on Inverter in motorhome
etwo4788 Offline
Member

Registered: 08/28/04
Posts: 518
Loc: S.E. New Mexico USA
BEBOP.....From beautiful sunny Yuma, AZ....in an I-Net cafe ... My MoHo is over the CO River Bridge on the CA desert!

My experience with all 5 of my Technics KB's running in the MoHo....All have done fine on one of those little 250 watt plug-into-a-12volt outlet. I am talking about the 1K, 3K,5K,6K...& the AWESOME 7K!

The 7K runs at top volume, a subwoofer, a mic, & I have turned on the 60 watt lamp also! There is no noise from the little Power Star inverter! It is an early model....I bought it for around $100 early in my boondocking days....probably about when I bought my first KB in '94? It runs like a champ! I can make lot's of noise!

Have a great trip! Stop by the Ranch to say hello along your way to FL! Maybe even stay a day or two for a bit of jamming??

HAPPY TRAILS.....ELIZABETH

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#44087 - 12/20/04 06:01 PM Re: Requesting info for running keyboards and amps on Inverter in motorhome
manorcourt1991 Offline
Member

Registered: 07/17/02
Posts: 235
Loc: Melbourne, Victoria, Australia
Hi Bill,

Modified Sine wave inverters (sometimes called modified square wave inverters) are common these days and are considerably cheaper than pure sine wave inverters. Essentially they produce a square wave but with a dwell at the zero crossing point so that the waveform is a crude stepped square wave. A friend uses a 150 watt one with his KN6500 and seems happy. As Chuck mentions you may experience some background noise in your keyboard or amps although my friend hasn't complained about this. A pure sine wave inverter should also be perfectly satisfactory with your keyboard and have no noise problems but will be more expensive. Incidently if you measure the output voltage of a modified sine wave inverter with an ordinary voltmeter the indicated voltage will be about 90 volts not 115. This is not a fault with the inverter but is due to the measuring circuitry in most common voltmeters. The only adverse comment I have seen about modified sine wave inverters is that if used with a laptop for a prolonged period of time the laptop battery pack may be damaged. Whatever inverter you choose it is necessary to ensure that it will supply the initial startup surge current drawn by your equipment.

Cheers
Len C.

[This message has been edited by manorcourt1991 (edited 12-20-2004).]

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#44088 - 12/20/04 06:30 PM Re: Requesting info for running keyboards and amps on Inverter in motorhome
Chuck Piper Offline
Member

Registered: 01/17/02
Posts: 403
Loc: United Kingdom
Hi Len,

I guess my comments date me. I had never heard of a modified sine (square) wave inverter. But then I've been out of the electronics field for 20 years and haven't worked with an inverter for at least 35 years. The RV I had in the 1970s had an inverter but the output was a more or less pure sine wave, heavily filtered to suppress noise. I've learned something. Thanks, Len.

Chuck

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#44089 - 12/20/04 07:09 PM Re: Requesting info for running keyboards and amps on Inverter in motorhome
BEBOP Offline
Senior Member

Registered: 01/02/00
Posts: 3770
Loc: San Jose, California
Thanks Chuck and Len for your responses.
One of the concerns I have is that the square Wave swings from 0 to 120 volts positive and then to 120 volts negative creating the square wave. It is ok for resistant loads like incandescent lights, coffemakers, toasters, hair dryers and such but not very good for electronics.
The modified Sine Wave (quasi) swings to 150 volts positive and negative. in stair steps. This creates background hum.
The sine wave utilizes microprocessors to mix the output of multiple transfoermers to attain a waveform that simulates a sine wave. This gives a waveform that is compatible with all AC equipment. However this sinewave swings from 170 volts to 0 to 170 volts.
This is the best for all electronic equipment however, I wonder about the much higher voltage. Is this going to be a problem with non resistant devices such as electronics. This hi frequency inverter uses H-bridge, high-voltage. It uses no heavy transformers so is lighter and less expensive. But........what about this voltage of 170. What will it do to the keyboards and amps either short or long term?
Please comment on this and thanks
Bebop
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BEBOP

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#44090 - 12/20/04 07:12 PM Re: Requesting info for running keyboards and amps on Inverter in motorhome
BEBOP Offline
Senior Member

Registered: 01/02/00
Posts: 3770
Loc: San Jose, California
Thanks Chuck and Len for your responses.
One of the concerns I have is that the square Wave swings from 0 to 120 volts positive and then to 120 volts negative creating the square wave. It is ok for resistant loads like incandescent lights, coffemakers, toasters, hair dryers and such but not very good for electronics.
The modified Sine Wave (quasi) swings to 150 volts positive and negative. in stair steps. This creates background hum.
The sine wave utilizes microprocessors to mix the output of multiple transfoermers to attain a waveform that simulates a sine wave. This gives a waveform that is compatible with all AC equipment. However this sinewave swings from 170 volts to 0 to 170 volts.
This is the best for all electronic equipment however, I wonder about the much higher voltage. Is this going to be a problem with non resistant devices such as electronics. This hi frequency inverter uses H-bridge, high-voltage. It uses no heavy transformers so is lighter and less expensive. But........what about this voltage of 170. What will it do to the keyboards and amps either short or long term?
How will this effect the deep cycle battery bank?
I am thinking of a permanently installed solar panel to keep the batterys up when they are not being charged by the converter or generator or engine alternator.
Please comment on this and thanks
Bebop
_________________________
BEBOP

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#44091 - 12/20/04 09:04 PM Re: Requesting info for running keyboards and amps on Inverter in motorhome
manorcourt1991 Offline
Member

Registered: 07/17/02
Posts: 235
Loc: Melbourne, Victoria, Australia
Hi Bill,

Peak voltages (positive or negative) of 170 should not harm your equipment. The normal peak voltages from your 115 mains power are around +/- 162 volts so 170 volts peak is only around 4% up on this. The normal mains power supply fluctuations probably exceed this.
In choosing solar panels you need to know the actual output of the panels in a practical installation. This is generally considerably less than the manufacturers stated output so it is important to seek expert advice to achieve a satisfactory result. I don't know about costs in the USA but here in Australia it can be a fairly expensive excercise.

Cheers
Len C.

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#44092 - 12/21/04 01:48 AM Re: Requesting info for running keyboards and amps on Inverter in motorhome
Chuck Piper Offline
Member

Registered: 01/17/02
Posts: 403
Loc: United Kingdom
Hi Bill,

Theoretically speaking, transient peaks are not a problem. They are of such short duration that they pose no danger to a keyboard, lightbulbs, coffee pots etc. Such peaks would only be a danger if they are sustained. I suppose that is obvious but I'll say it anyway.

It appears to me that the output of the inverter you are intending to use is digitally derived. The inverters I am familiar with were DC motors that produced a sine wave output. Apparently your inverter is a solid state device, hence the modified sine wave or square wave output.

I think Elizabeth and Len are likely right in saying your inverter will not damage your keyboard. But just to be on the safe side I would telephone the manufacturer and ask for specific assurances that the output of the inverter is safe for keyboards. They have to have a toll free number. Manufacturers do not always take into account ALL of the possible appliances out there when they design and manufacture their products. I am like you. I would want to be on the safe side, so I would telephone.

Merry Christmas to you and Jann,

Chuck

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#44093 - 12/21/04 04:42 AM Re: Requesting info for running keyboards and amps on Inverter in motorhome
shcox Offline
Member

Registered: 09/10/03
Posts: 296
Loc: Leesburg, FL USA
Hi BeBop,

The wave type should not be a problem. The actual electronics of the keyboard does not run on AC anyway. All electronic these days have there own voltage regulators in them which allows for power fluctuations. The AC is converted to DC and regulated to the proper voltages. The incomming wave form would have little to no effect as long as it is 60 hz.

In fact I'd bet that the KN7000 could be run on batteries if it were not for the power required to run the amp. Which is one reason they sound so much better than keyboards that can be run on batteries.

If you can run a small TV on you converter then the Keyboard should cause no problems.

Seasons Greeting

------------------
Heather- Leesburg, FL PR54

[This message has been edited by shcox (edited 12-21-2004).]

[This message has been edited by shcox (edited 12-21-2004).]
_________________________
Heather- Leesburg, FL PR54

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