Tube Amps / Music Electronics
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|previous: Steve Dallman Just some other thoughts...this amp... -- 1133556900||View Thread|
|12/2/2005 2:44 PM|
|Steve Dallman||Re: installing external speaker jack on roland microcube amp|
Besides the external speaker mod, and a footswitch mod which can be found on the site I linked earlier, here's another "useful" mod...
I would like to be able to use the phones/record out at the same time as the speaker is working.
There are 7 pins on the record out. Strangely they are numbered 1, 2, 3, 4, 5, 7, 8. Pins 7&8 are shorted when nothing is plugged in. Pin 8 goes to the #2 position of that board's ribbon cable. Pin 7 goes to the battery ground, which is the electrical ground...not to be confused with the chassis ground.
Pin 8 goes to the "phones detect" pin of the CPU. When pins 7&8 are shorted togther the CPU thinks there is nothing plugged in, and the power amp runs as normal. When the connection between these pins is broken, the CPU shuts down the power amp.
Adding a SPST switch to short 7&8 together even when something is plugged into the rec out/phones should keep the power amp on.
I'm not sure what type of switch to use or where to mount it. I want to maintain the basic look of the amp so any switch I use should look like the other switches.
When considering modding this amp, remember MY motto...
"If I can't fix it, I'll fix it so no one else can."
There are a couple other signs in my shop. One is
"Jesus is coming!...Look Busy!"
and one left over from the maintenance shop at the plant I used to work at...
"Do it Right the Third time."