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Author Topic: New Member Roland Cube 20 Orange question  (Read 9447 times)

monfi

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Re: New Member Roland Cube 20 Orange question
« Reply #15 on: September 25, 2015, 05:00:32 AM »
Tnx J M Fahey. :tu:
Ok, this is my final idea...in this weekend I hope to go buy components, i made it on breadboard and after i think to solder it in perfoboard. :dbtu:
I've marked R13 because in schematic not have value, I've put it 1 in my schematic on multisim...is correct?
The same for diode 752, i've put 1n752a...is right?  8|

J M Fahey

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Re: New Member Roland Cube 20 Orange question
« Reply #16 on: September 25, 2015, 11:43:48 AM »
Tnx J M Fahey. :tu:
Ok, this is my final idea...in this weekend I hope to go buy components, i made it on breadboard and after i think to solder it in perfoboard. :dbtu:
I've marked R13 because in schematic not have value, I've put it 1 in my schematic on multisim...is correct?
The same for diode 752, i've put 1n752a...is right?  8|
Ok:
1) R13 sets the maximum preamp gain , which is 1+(22k/R13) .
Typical values are 1k so gain is ~11 and 470 ohms, where typical max gain is ~21 .
Both are fine for a typical guitar.

2) don't know what a 1N752 is, but the idea is to protect the amp if you connect the battery the wrong way, so the minimum diode to be used there is a 3A 1N5402 but better one known as "6A2" , looks like a fat 1N5402 but is rated 6A instead of 3 .
Others might suggest more modern options.

Lead acid batteries can supply, say, 30 to 50A for a few seconds and NUKE the amp, maybe even make it catch fire.
Lithium ones can pass 100 amperes and the batteries themselves catch fire or explode like grenades.

FWIW one of the presumed causes of Malaysia Ailines flight to Beijing dissapearance is that a 200kg case of LiPo batteries it was carrying in its cargo bay caught fire and exploded.

They are *that*  dangerous.

Many airlines won't let you board a plane carrying an extra spare battery for your notebook or smartphone.

So added protection in the amp is not a bad idea.
Also add a 4A or 5A fuse *close*  to the battery.

monfi

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Re: New Member Roland Cube 20 Orange question
« Reply #17 on: September 25, 2015, 03:44:21 PM »
I not think to use amp out of house so i put a fuse ti be more safety but I put a power transformer 200 to 12 500mA or 1 A ???

inviato e basta :)