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Alembic Club » Alembic Basses & Guitars » Archive through January 07, 2011 » Archive: 2009 » Archive through May 01, 2009 » Would changing the voltage of an Amplifier change its sound? « Previous Next »

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grass903
New
Username: grass903

Post Number: 6
Registered: 2-2009
Posted on Tuesday, April 07, 2009 - 9:28 pm:   Edit Post

Hi.

This question has nothing to do with Alembic products, but I thought you guys could help me, so..
please give me some advice.

So. I have an SWR SM series amplifier.
I bought it through Bass central in the US,
so it's power is setted to be used in the US,
which is 100V(or 110V somewhere).
As you know-or not-, the power voltage used in
Korea is 220. I guess if I just plug this amp
in, then I'd see some smoke.
There I thought of modifying the amp's power
section to 220V. I asked a guitar engineer
who I know, who doesn't make me perceive his
comments seriously due to his over proud, then
he said I should better not do it because it would
change the amp's sound characteristic completely.
I thought if there will be any change, then it'll
be very subtle, but he was so sure about it,
and in the end, his face was almost like
'You don't even know that, punk?' looking down
kind of face, and actually I'm not a pro in this
field, so I need to get some more info.

People! Help me again!
lbpesq
Senior Member
Username: lbpesq

Post Number: 3675
Registered: 7-2004
Posted on Tuesday, April 07, 2009 - 9:31 pm:   Edit Post

I have an original Boogie Mark I that a a variable voltage dial on the back, so it can travel the world. So it can be done.

Bill, tgo
slawie
Member
Username: slawie

Post Number: 69
Registered: 8-2002
Posted on Tuesday, April 07, 2009 - 10:41 pm:   Edit Post

If you plug the amp in that has been transformer tapped at 100V for US into a supply that is 220V for Korea you will let the smoke out of the components.
Without having a wiring diagram it is difficult to say what will fry but there should be a inrush protection fuse on the primary side of the internal transformer.
Differences that may occur are to do with the frequency of the input voltage.
60Hz for USA and 50Hz for Korea.
You can buy a step down transformer with a high VA (Volts x Amps) rating which is the product of the line voltage times by the amplifiers current draw this equals the wattage of the amp, not to be confused with the audio wattage. If you look on the back of the amp a litle tag should should state the VA rating. Over compensate! If it says 350VA go for 500VA rated transformer.
The manufacturer of the amp may have a replacement part transformer that you can fit after you buy from them. Or there may even be input tapping (primary side) coming to the transformer that can be switched across to another line voltage.

None of this probably helps.

slawie
jimmyj
Junior
Username: jimmyj

Post Number: 47
Registered: 8-2008
Posted on Tuesday, April 07, 2009 - 11:08 pm:   Edit Post

Jongsu,

Get a second opinion! Maybe the guy you asked just didn't want to do the work...

The power transformer or power supply board on the inside of your amp may have jumpers which would allow you to have it modified to run on 220v. Don't try to do this yourself, bring it to an amp repair guy and ask them to open it and take a look.

If there is no such internal option then your choices are limited to:
A - ordering a replacement 220v internal transformer from SWR and having it installed, or
B - using an external transformer (with a high enough current rating) to step down your 220v line voltage to 110v.

As long as the output voltages of the internal power supply are correct the sound of the amp will NOT be effected by the input voltage.

Good luck,
Jimmy J
terryc
Senior Member
Username: terryc

Post Number: 765
Registered: 11-2004
Posted on Wednesday, April 08, 2009 - 4:53 am:   Edit Post

I was under the impression that most modern amps are voltage switchable to make them internationally accepted.
My old USA Peavey TNT115 has a voltage selector, surely a company as good as SWR would include this option on their gear??
longhorncat
Advanced Member
Username: longhorncat

Post Number: 303
Registered: 8-2005
Posted on Wednesday, April 08, 2009 - 11:54 am:   Edit Post

From SWRsound.com

Q: I'm moving to a different country. How do I change the voltage of my amplifier so that it's compatible?

A: If you plan to use an SWR amplifier that was purchased in North America in a country outside of North America, it will be necessary to change the unit's voltage so that it's compatible with the foreign country's electrical system (as with any electronic product you intend to use overseas). SWR amplifiers purchased in North America are designed to run on 120 volts; foreign current is generally 220 volts.

If you want the voltage of your amplifier changed permanently (for a relocation or long-term move), we recommend that you have a replacement power transformer installed in the unit's chassis. This modification can be made by any qualified Authorized FMIC Service Center. If you would like to permanently convert the voltage of your amplifier by replacing the internal power transformer, click here to locate an Authorized FMIC Service center near you.

Please note: SWR Professional Series models built before March 1999, feature multi-tap transformers and can be wired for 110v, 120v, 220v or 240v. A schematic for this purpose may be ordered from SWR by calling 480-596-7195.

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