roland cube 40xl line out and speaker out at the same time

[johnjohnjohn]

Hello , has anyone had succes on modding this amp to get a line out without unmutting the speaker. I have researched and found this schematics
http://www.freeinfosociety.com/elect...ew.php?id=1326
and also one other page where it says you have to solder pin 3.7 and 2.6 and it should work, but will this damage the amp?

[52 Bill]

Hello , has anyone had succes on modding this amp to get a line out without unmutting the speaker. I have researched and found this schematics
The Free Information Society - Roland Cube 40 Electronic Circuit Schematic
and also one other page where it says you have to solder pin 3.7 and 2.6 and it should work, but will this damage the amp?

I've never done it, but based on the schematic jumpering 3-7 and 2-6 will keep the speaker on when the headphones are plugged in.

This should not cause any problem with the amp.

[J M Fahey]

Are you talking about line out or headphone out? Not the same.

EDIT: beware that the modern Cube 40XL is *not* the same , specially not the same schematic, as the 80's Cube 40 you found.

[johnjohnjohn]

Are you talking about line out or headphone out? Not the same.

EDIT: beware that the modern Cube 40XL is *not* the same , specially not the same schematic, as the 80's Cube 40 you found.

Hey do you know if it will work on cube 40xl?

[J M Fahey]

Sorry, never saw the XL schematic, too new.
Post a sharp well illuminated picture of the phone jack, both sides of the PCB, maybe it's a common type and can suggest something.
In general plugging a headphone opens the speaker ground return, but don't dare suggest anything "blind".

[johnjohnjohn]

Sorry, never saw the XL schematic, too new.
Post a sharp well illuminated picture of the phone jack, both sides of the PCB, maybe it's a common type and can suggest something.
In general plugging a headphone opens the speaker ground return, but don't dare suggest anything "blind".

Hey before I do this , do you think it should work? I dont want to get electrocuted or something while playing

I found out this schematic which is for a 15xl wich I think should be close to the this http://music-electronics-forum.com/a...-cube-15xl.pdf

[J M Fahey]

Well, in the 15XL the earphones are *always* connected to the power amp speaker out through resistors R80/81/83 , and the main speaker line is *open* at contacts 4 and 5 on the headphone jack, when you plug a headphone there.
If you bridge/junper those 4 and 5 contacts with a piece of wire, the speaker will *^not* mute.
Of course those numbers are valid for the 15XL, check yours.
And no, you won't get electrocuted unless you connect one speaker wire to each ear and play a full chord and I'm not kidding.

[johnjohnjohn]

Well, in the 15XL the earphones are *always* connected to the power amp speaker out through resistors R80/81/83 , and the main speaker line is *open* at contacts 4 and 5 on the headphone jack, when you plug a headphone there.
If you bridge/junper those 4 and 5 contacts with a piece of wire, the speaker will *^not* mute.
Of course those numbers are valid for the 15XL, check yours.
And no, you won't get electrocuted unless you connect one speaker wire to each ear and play a full chord and I'm not kidding.

Here are the pics for the lineout/phoneout jack

[J M Fahey]

Mmmmmmhhhh, don't know that jack.
I suggest that, with the amp off and unplugged, you trace it backwards, meaning you start from the speaker "hot" terminal, follow its cable back into the amp, then the track on the PCB, until you touch one pad from the headphone jack.
Plug and unplug repeatedly a spare plug there, and you should be able to identify, with absolute certainty, another pad from the same jack which gets disconnected from the speaker pad with the plug "in" and reconnected with the plug "out".
For more certainty disconnect one terminal from the speaker itself.
Once you are sure, join both jack terminals with a piece of wire.
Reconnect everything, play some music (MP3, radio, etc.) into the amp so you have your hands free and your full attention on the amp and plug the spare plug into the earphone jack.
The speaker should not turn off.

[johnjohnjohn]

Mmmmmmhhhh, don't know that jack.
I suggest that, with the amp off and unplugged, you trace it backwards, meaning you start from the speaker "hot" terminal, follow its cable back into the amp, then the track on the PCB, until you touch one pad from the headphone jack.
Plug and unplug repeatedly a spare plug there, and you should be able to identify, with absolute certainty, another pad from the same jack which gets disconnected from the speaker pad with the plug "in" and reconnected with the plug "out".
For more certainty disconnect one terminal from the speaker itself.
Once you are sure, join both jack terminals with a piece of wire.
Reconnect everything, play some music (MP3, radio, etc.) into the amp so you have your hands free and your full attention on the amp and plug the spare plug into the earphone jack.
The speaker should not turn off.

Hey thanks for your help , ok I traced that the speaker red cable goes where I put the red circle, but how do I know wich is the other pin I have to solder? I didnt quite get it

[johnjohnjohn]

this is the website for the jack , dont know if that will help
http://www.jalco.co.jp/eng/products/...hone_jack.html

iit is jalco PJ9 3c I think

[DrGonz78]

Basically the fastest way to test for this is with your multimeter set to test for continuity. Touch one tip of your meter to speaker terminal that you pinpointed in that other pic and then test all the remaining legs for continuity. What you are looking for is the leg that gets shunted as you plug something in. So in other words it will beep with continuity and as you plug it in that will cut the signal. Look for which leg is involved for turning off the speaker.

[J M Fahey]

And remember to disconnect at least one terminal at the speaker, or you will measure continuity *through* it, which will cheat you.

[johnjohnjohn]

And remember to disconnect at least one terminal at the speaker, or you will measure continuity *through* it, which will cheat you.

Hello friends aparently it is working I did the multimeter thing, and tested with an ipod, before I connect my gutiar or the PA , I just want to ask you if im in risk of electric shock or somethng like that lol. .. or what could be the worse that could happen?

update
I already tested it on the PA with very low volume it works I didnt want to turn the volume all the way up until I received feedback from you.. one thing I noticed is that the amp sounds diferent if I conect the headphone/lineout cable.

[J M Fahey]

Cool, it works.
1) no, no extra risk of electric shock because of this mod.
Anyway you must always connect your amp to a properly grounded outlet.
2) the only possible error would be to mis identify the jack legs and short the power amp output or something, but it looks like it did not happen.
3) *maybe* some contact shorts the current feedback resistor when in "headphone mode" to make it less buzzy, this would change somewhat the sound through the speaker.
Just an educated guess, of course.