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Circuitbenders Forum => Circuitbending discussion => Topic started by: boneless on October 13, 2008, 02:35:53 PM

Title: unwanted line out noise
Post by: boneless on October 13, 2008, 02:35:53 PM

hello all.

at the moment I'm working on an SK1 - just fitted highly liquids MIDI retrofit (http://highlyliquid.com/) which works great - and starting to put some bends in.

I've removed the speaker and put in a line out.

1k resistor to ground, 10k with 10uf cap to line out.

My only problem is a constant high pitched noise in when plugged to speaker (it sounds like some kind of oscillation)

Anyone any ideas why this is happening?

(it's darn annoying!)

Title: Re: unwanted line out noise
Post by: PolyPhuckin on October 13, 2008, 09:21:34 PM

That sounds more like you've built a filter rather than a PAD device. (though i may be wrong)

This page is really useful http://www.epanorama.net/circuits/line_to_mic.html its really handy

Title: Re: unwanted line out noise
Post by: Circuitbenders on October 13, 2008, 09:46:56 PM

Surely the SK1 already has a line out on a minijack? Why would you need to wire up a line out from the speaker?

Title: Re: unwanted line out noise
Post by: Gordonjcp on October 13, 2008, 11:37:28 PM

If you're taking it from the speaker, then it's a speaker out ;-)

Take the line out from the volume control, possibly with the aid of a little buffer amp.

Title: Re: unwanted line out noise
Post by: boneless on October 14, 2008, 09:22:19 AM

You're right I did just wire my  speaker wires to my line out - I figured if i was removing the speaker I might as well do sommit with the wires! (and I thought it  would be easier to have a  1/4jack plug as I always seem to lose my adapters....)

will check my arangement of resistors and cap again - and if that don't work try taking my line out from vol control.

The weird thing I've just found is that the noise appears on the SK1's mini-jack line out as well. It wasn't there before I installed the MIDI retrofit.

Thanks

Title: Re: unwanted line out noise
Post by: SineHacker on March 03, 2009, 11:31:50 PM

you may be picking up some electronic interference, you might need to use a shielded cable at some point in your modifications rather than just a normal unshielded one. Strip about an inch or two (depending on the length you need) from the cable then twist the shield away from the core. You want to solder either end of the shield to somewhere it can ground, for example the negative side of the bat compartment (screws are usually ok as well, use a multimeter to be sure).

on the other hand this may not be the case at all  :D


good luck!