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Opening up Roland Cube 40XL


Jazzer2020

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Has anyone here done it?

Or say Cube 80XL, or Cube 30 or Cube 20 etc.?

 

I've got pretty much every screw off from the back/top and the chassis still is fighting for dear life to stay

inside!

 

I am ready to change the power cord from 2-prong to 3-prong as recommended by Freeman.

 

Won't be able to do it unless I can get the chassis out.

 

 

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I haven't but that's odd. My Cube 80XL has a 3 prong plug. I'd normally assume they came that way from the factory. :idk:

 

Interesting. Was it made for America?

I got the schematics for the 40XL or another and found something equally interesting.

They had in the schematic two different plug options!

A 2-prong plug for 120v and a 3-prong for 220v !!!

The nerve!

 

BTW, my Cube 30 which was made years earlier and is lower powered has a 3-prong plug.

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If you had looked at the schematic and understood what you were looking at it would be obvious what you were dealing with here. You have to change the cord, the switch, add two caps and make sure the amp is wired for 220V not 100V.

 

This amp has three versions. A 100V version, a 117V version and the 220V version. If you look towards the bottom of this schematic you'll see the 100V version that uses the 100V tap does not use an AC ground

 

[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"Cube%2040.gif","data-attachmentid":32265910}[/ATTACH]

 

 

 

I'm not sure what your country is but there aren't many countries that use 100V besides Japan (and Okinawa). If your amp has no ground then there is only two possibilities here. You are running your amp on a 100V transformer tap, or someone has taken a Japan only amp and rewired the transformer tap for 120V and failed to do the proper modifications to make it safe.

 

You have allot of shysters on the internet selling gear to anyone who pays and they could care less if its actually designed to run in the proper country.

 

 

The problem you face however, is you don't know what other changes involved with a 100V 50HZ conversion to 120V 60HZ.

 

As a technician for major manufacturers I deal with this kind of stuff on a daily basis. Most of the gear companies sell come from Japan or China so you're always dealing with the Inch vs metric and differences in voltage. Normally they ship the right voltage versions but during times of product shortage they might send an overseas version and we have to modify to our country so they pass UL inspection.

 

I've done thousands of these kinds of conversions over the years and some can be much more involved then you think. On amplifiers, you typically don't have to worry about the differences in Hertz unless there is a motor of some sort involved. Done properly a manufacturer provides a kit for the conversion and the components swapped can vary depending on the piece of gear involved. Its unlikely you're wrangle a kit out of Rolland to convert this amp unless you are am authorized dealer.

 

If I can trust this diagram I think you'll be OK adding the ground but you MUST check and see if the AC is connected to the 120V tap. The way you check is to remove the fuse and do an ohm meter check across the primary tap. Then find the third primary wire not being used. It typically has heat shrink or is taped off then read the ohms between it and neutral.

 

Whichever measurement is higher is your 120V tap and is what should be used in a 120V country.

 

The other thing you must do is install a dual blade on off switch.

 

You also need two install (2) X .047 non polarized cap 220V (twice the line voltage) across each side of the switch. This will prevent loud pops when you turn the amp on and off and allow the voltage to drain off slow when you power down. This saves the switch and prevents the circuits from being zapped.

 

I'm not sure why they leave the .001 cap between the fuse and ground. Typically that Death Cap as its typically called is removed when a grounded cable is added but it can likely stay so ling as its in good shape.

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It turns out the US version of the Cube 40XL only has a two wire cord. From the Manual (emphasis added):

(for CUBE-80XL only)

Connect mains plug of this model to a mains socket outlet with a protective earthing connection.

Incidentally, Okinawa is part of Japan. Saying "Japan and Okinawa" is like saying "The US and Texas."

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Thanks WRG. Now you've got me thoroughly confused.

BTW I did look at the schematic. That's how I knew there grounded and non-grounded versions.

 

 

If you had looked at the schematic and understood what you were looking at it would be obvious what you were dealing with here. You have to change the cord, the switch, add two caps and make sure the amp is wired for 220V not 100V.

 

This amp has three versions. A 100V version, a 117V version and the 220V version. If you look towards the bottom of this schematic you'll see the 100V version that uses the 100V tap does not use an AC ground

 

 

I'm not sure what your country is but there aren't many countries that use 100V besides Japan (and Okinawa). If your amp has no ground then there is only two possibilities here. You are running your amp on a 100V transformer tap, or someone has taken a Japan only amp and rewired the transformer tap for 120V and failed to do the proper modifications to make it safe.

 

My country is Canada. 120V.

 

If I can trust this diagram I think you'll be OK adding the ground but you MUST check and see if the AC is connected to the 120V tap. The way you check is to remove the fuse and do an ohm meter check across the primary tap. Then find the third primary wire not being used. It typically has heat shrink or is taped off then read the ohms between it and neutral.

 

Whichever measurement is higher is your 120V tap and is what should be used in a 120V country.

 

I checked the easy way.

Back of amp says:

 

AC 117V 50/60 Hz 43W

Model: Cube-40XL

Serial Num. xxxxxxx

Made in China

 

So I have the correct version for North America.

 

Now why I am confused?

If you say I need to install a dual blade on off switch and

two .047 non polarized cap 220V across each side of the switch

why didn't Roland do it themselves?

 

 

 

 

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Well I made a trip to my hardware store because the local electronics store was closed.

As I expected they did not have either of the items I was looking for:

-Female lugs the right size to plug into the power connector board.

-A nut that will attach to a chassis screw (so I can attach the ground wire).

 

So question about the lugs.

Will it work just as well if I splice together near the end of the power cord?

That way I can still use the lugs that I have now.

I would cut off the end of my old power cord and splice it to the end of my new power cord.

 

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When it comes to AC wiring you shouldn't mess around. Far too dangerous to splice anything and becomes a fire hazard. You should do the job properly or not do it at all. What is the purpose of switching from an ungrounded to a grounded cord is you make the amp a fire hazard on the process

 

I'm not sure what these lugs are you're talking about without seeing a pic. I suspect they are flat self locking clips that connect the wires. It might be possible to trim them off the old cord and solder them to the new cord but given the heavy wire gauge you typically need a heavy duty soldering iron to get enough heat. Wires could be soldered directly to the board too. The tabs are typically soldered to the board and can be extracted and the wires soldered direct.

 

Truly, I'm really not sure why you're even messing with this it in the first place. If its wired for 117 the cable should have one plug pin that's larger preventing you from plugging the cord in backwards. You'd have to willingly override that safeguard to have any risk of shock.

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"Truly, I'm really not sure why you're even messing with this it in the first place. If its wired for 117 the cable should have one plug pin that's larger preventing you from plugging the cord in backwards. You'd have to willingly override that safeguard to have any risk of shock."

 

Yes the plug had one pin larger than the other. I did the re-wiring on the advice of Freeman.

He strongly urged me to do it.

 


 

 

 

 

 

 

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Could use your advice on this one now..

 

I did mod the Cube 40XL, taking out the 2-prong plug and adding a grounded 3-prong plug.

Roland said it wouldn't make a difference, unless playing in a high-powered situation.

 

I changed my mind about it a couple of days later and put back the 2-prong plug.

 

Fast forward to today...

I get out my ES-175 P90 and plug her in to the 40XL (intending to find the sweet spot from 'Amazing Discovery' post).

 

HUMMMM........

 

Really annoying!

Other than the hum, the sound was really nice. :(

 

I suspect the P90 + no ground (because my humbucker guitars have no hum at all).

 

I do an A/B test with my Cube 30 which has a 3-prong plug.

 

Cube 30, NO hum at all.

Cube 40XL, hum.

 

So my questions.

1. Would you recommend I add the 3-prong plug to the 40XL again?

2. Will it fix the hum completely?

 

If I put my foot on the top of the amp, touching the metal part of the handle, the

hum goes away completely.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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