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Kaboom Power Supply


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#1 Ken

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Posted 14 December 2011 - 10:53 AM

Thinking about buying a Victor Kaboom. Accordingly, it has a 100V power supply instead of a 110V. :yes:

Swap, maybe? Don't really want to be limited to 12V & batteries. :hmmm:

Anyone? :huh:

#2 blu_fuz

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Posted 14 December 2011 - 11:35 AM

Same as my Victor M70...... I run it on a regular power cord with 110v/120v outlet :yes:

Some say it's not safe, but I have had this Victor M70 powered on for more than 9 hours at a time on the cord and there are no issues.

#3 Ken

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Posted 14 December 2011 - 05:28 PM

Same as my Victor M70...... I run it on a regular power cord with 110v/120v outlet :yes:

Some say it's not safe, but I have had this Victor M70 powered on for more than 9 hours at a time on the cord and there are no issues.

Yesteryears electronics made be built to withstand a lot, but you should run it at the proper voltage.

Otherwise a priceless collectible becomes nothing more than a fire hazerd... :nonono:

There's gotta be a swap, methinks...

#4 Superduper

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Posted 14 December 2011 - 11:38 PM

transistors, and other older solid state components have very wide operating voltage ranges. New boomboxes are populated with virtually all IC's which are very specific in terms of voltage requirements. For the most part, the rails powering the components would be protected with voltage regulators. however, higher voltages means the regulators will be sinking a lot more current. Our USA power will increase voltage by 25% over Japanese mains. The sinking requirement could increase by far more than 25% though. Here's why:

A 12v regulator fed 18 volts will sink the current produced by the 6 dropping volts. The same regulator fed with 22.5 volts (18v + 25%) will be sinking 10.5 volts. If you do the math, you will find that the difference between sinking 10.5v vs 6.0v = a 75% increase in voltage, which will generate a commensurable amount of current for the regulators to sink.

#5 sv1hao

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Posted 16 December 2011 - 12:34 AM

1) use a transformer to bring your AC to 100V (don't need a big one) 100watt should do and may be a overkill.
2)use a power supply to feed you boom box directly with DC (computer power supply may be a option)
3) just use it on 110 (please read notes below)
Boom Boxes have a transformer in it that "lowers" the AC 110/220 to the the needed voltage
that could be 12/9/5/3 volt depending on the model ect.
and this is the trick....
if you have a 100 volt transformer that "converts" to 10V (depending on circuit) and feed it with 110v you will practically get 10% more in the circuit.
so instead of 10V in to the circuit you will be feeding it with 11V (big deal)
another example is that a lot of electronics ask for 12volts but they happy are fed with 13.8V ;)
Super duper has a point about the regulation and should be noted for long term use (years)
if you mains are 110v i would use as is.
if more do options 1 or 2 stated in the beginning of post.

to get a better answer what is your mains voltage
and what is the DC voltage for the boom box

regards

#6 Superduper

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Posted 16 December 2011 - 02:56 AM

@sv1hao:

A few clarifications. First, the OP is speaking specifically to the Kaboom. Not a generic boombox so generalities is not helpful. Other discussions have already taken place regarding this issue in general. For the record, the kaboom power supply on Mains supply 19.3v at the rails to the kaboom circuitry.

Secondly, our USA mains is seldom 110v. It's more like 120v and around here, it's more like between 122 to 127 volts. Today, I just measured voltage at 122 volts. I have never ever in all my years read 110 volts in this area. Last month, it was 127 volts. I think it's fair to say that our typical mains voltage here would be 22% to 27% higher than the 100v japanese voltage.

So while your theoretical 10/11 voltage ratio is, in your words, "no big deal." Let's change the voltages to real world voltages. For the kaboom, it would be more like 19.3/23.5 or 19.3/24.5. I would say a 4.2 to 5.2 volt increase is certainly substantial. And while typical electronic design will build in a little extra room for error, running it at 25 to 27% over specs continuously will certainly take it's toll over time on the regulators, of which the kaboom has many. Finally, while most of the digital circuits in the kaboom have exacting voltge regulators, the amps are fed the full rail voltage. This is typical for most boomboxes. I'm not going to suggest that the kaboom amps can't handle the extra 5 volts. However, I will say that when operated with higher than design voltage, and operated at or near max volume, the amps could be stressed and possibly blow prematurely. Amps will usually produce output commensurate with the supplied voltage. Higher input voltage usually means higher output potential. If designed that way with proper heatsinking, etc, no problem. If not, then watch out. The kabooms, even when operated at normal voltage generates lots of heat at the radiators. Are they sufficient to handle the excess? I dunno. Also, are the chips designed to operate safely at 24.5v? I dunno either. But suffice to say I'm not prepared to say it's no big deal. Remember, the kaboom has a 12v DC input. 24.5v is more than double that.

#7 sv1hao

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Posted 16 December 2011 - 04:04 AM

Thank you for giving a clearer picture about this specific box.
My figures suggested a 100 to 110 volt (10%) which as you kindly describe
is not real in this case. And I totally agree with your approach.
Pushing at 122 to 127 volts is a problem and should NOT be plugged directly to mains.
The life of the box will certainly shorten (burning the candle from both ends).
I understand your consideration about the extra voltage on the finals and the regulators and agree that there will be extra stress on the components .“Burning” the extra volts to heat is a waste of energy and not good for the box.
Our friend states that “Don't really want to be limited to 12V & batteries”
So I think that you will agree that the options are
1) A small step-down transformer 120v to 100v to feed directly from mains.
2) A switched power supply to feed to DC directly .(12vinput or to battery’s)

This is the easiest –cheapest way to solve the problem in my opinion if our friend wants to keep the Box.
This way the box is happy again and the owner as well.

regards

#8 Ken

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Posted 16 December 2011 - 07:08 AM

:thankyou: :thumbsup:

You guys answered all my questions...just as I thought, Some transformer or a different power supply sure sounds like the way to go. I get as much as 125V at my house sometimes and it never drops below 118V.

I really don't want to do an arc & spark test to see if it would actually fail, though. I may not buy the box if I can't work out something with the seller, as I want an older Kaboom w/ tape player & this one has a lot of damage.

:hmmm: :hmmm: :hmmm: