Convert new GK MB200 110V to 240V

Groove Doctor

Groove Doctor

Feb 23, 2009
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Sydney, Australia
#1
Just need some clarification....

I've been following the thread for converting an MB500, bought a new MB200 (Sam Ash heavily discounted)... BUT.... the MB200 is different inside.

Can somebody clarify what I'll need to do to switch a 110V model to use in Australia 220-240V?

Or, is it rated for both voltages? Just labelled for 110V?? (hence, safe to use at 240V as is??)


Gut shot
38FACDFF-4854-42FF-9F4F-471179690C28_zpsjskrdtph.jpg



Clip (vertical) to the left of 230v/115v lettering.
466403DB-0737-47FC-B752-F7E1D95BB3BB_zpsveqq5sdl.jpg
 
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#4
Can you get a better angle on the clip 110/240? Yours appears different from mine, since sold.

Iirc there was a black plastic covered jumping wire clip which I moved over to the opposite position retaining the central pin. It was holding on tight. I fashioned a hook from a paper clip by work hardening and snipping it just so.
 
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#7
Groove Doctor said:
I'm away until Sunday.

Bottom left corner (next to power input). I'll send it thru ASAP.
Click to expand...
I don't know what you are looking at but first pic of post #2, says 115 250 on the board. The black plastic doofer pulls off and you shift it onto the next pin. Job done.

I made the hook because I feared crushing the doofer with pliers. Fingers couldn't get a good enough grip on it. It took quite a pull with the hook.
 
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#17
@Groove Doctor

Sorry to be reviving this thread - but i'm in a similar position (currently living in Japan/100v, and may at somepoint move back to Europe/230v).

Did the jumper-switch work? did the amp function normally thereafter, or were there fireworks?

The labelling on the version I have is very adamantly saying "100V only operation", but the circuitboard looks the same, including the 115/230 jumper

Thanks in advance to anyone who could confirm :)
 
#18
There may be additional control circuitry on the preamp board to support 100V operation. This is not uncommon. You might ask GK.
 
#19
May be a good idea to shoot GK a message, but I doubt there's anything special inside... when I opened the case of the amp, it looked the same as what was posted above. (something was rattling inside, so I had a look - turns out it was a just an old sticker that had been attached to the inner casing, but the glue had let go).

Apologies regarding the confusing info re: 100v operation. That was attached to one of the stickers outside, but on a different MB-200 (I have two, both original 'bought in Japan' spec).

What particularly confuses me is this.

On the back of the amp we've got this marking:
upload_2022-3-17_11-20-39.png


And on the top of the casing:
upload_2022-3-17_11-21-14.png



I'm not sure what to make of this?

Back input says: 100-120v 50/60Hz.
(so this makes me think that there is no 'Japan specific' circuitry vs the US model)

Top says: 120V 60Hz ONLY

... and I've been running these in Tokyo on 100V 50Hz and of course it's been fine.

On the other hand, I've heard horror-stories of someone plugging in US-spec electronics into the Japanese mains (e.g. pedalboard + power supply), and gotten 'magic smoke' and everything burned out.

Is this just matter of various certification standards?
 
#20
kumimajava said:
May be a good idea to shoot GK a message, but I doubt there's anything special inside... when I opened the case of the amp, it looked the same as what was posted above. (something was rattling inside, so I had a look - turns out it was a just an old sticker that had been attached to the inner casing, but the glue had let go).

Apologies regarding the confusing info re: 100v operation. That was attached to one of the stickers outside, but on a different MB-200 (I have two, both original 'bought in Japan' spec).

What particularly confuses me is this.

On the back of the amp we've got this marking:
View attachment 4624097

And on the top of the casing:
View attachment 4624099


I'm not sure what to make of this?

Back input says: 100-120v 50/60Hz.
(so this makes me think that there is no 'Japan specific' circuitry vs the US model)

Top says: 120V 60Hz ONLY

... and I've been running these in Tokyo on 100V 50Hz and of course it's been fine.

On the other hand, I've heard horror-stories of someone plugging in US-spec electronics into the Japanese mains (e.g. pedalboard + power supply), and gotten 'magic smoke' and everything burned out.

Is this just matter of various certification standards?
Click to expand...
It depends. That's why I suggested that you contact GK.
 
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