Easy (and possibly free) signal generator.

General rules and hints to succesfuly bring back that old pedal to life
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deltafred
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Post by deltafred »

I do quite a few pedal and amp repairs for a music shop so built a 1 kHz 2 transistor multivib signal generator with a 386 amplifier and a 3 inch speaker all in a re-purposed plastic box.

It works fine but the 1 kHz tone gets on your nerves after about 10 seconds so I started using my Strat as a sound source instead. This is not ideal as you have to keep strumming it and strummed open strings get old fast.

I then came across a set of sound samples that The G posted a couple of years ago and realised that I had an old mobile/cell phone gathering dust. (Very old as it is running Android 1.5 which was released in April 2009).

viewtopic.php?t=30860

I downloaded the guitar samples, put them on a 1 Gig SD card, inserted it in the phone and made a playlist of them.

I then got the 3.5mm jack and lead from an old pair of earbuds, soldered the L and R ground wires to the ground of a 1/4 inch jack plug and combined the L and R channels using 2 x 47k resistors to the tip connection (inside the jack cover).

It works perfectly. I no longer have to listen to my tuneless strumming or have my eardrums pierced by the 1 kHZ tone. I could record my own guitar (and bass) samples but being a lazy SOB probably never will.

Edit. I know I could use my current phone but am reluctant to plug it into unknown pedals and particularly tube amps.
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