Check the charity resale shop, or musician's exchange. The old mono guitar head equalizers with rotary potentiometers are really cheap. Usually any equalizer needs some new potentiometers, or at least a good potentiometer cleaning. The stereo slide pot Peavey one that came "free" with the speakers & amp I bought, needs new power supply caps. All this equipment was 1998 vintage; Peavey is a "quality" brand that buys electrolytic caps good for at least 10-15 years. When I go into old gear with problems, I replace all the electrolytic caps at once with ones rated 3000-10000 hours service life.
I actually bought a stereo 12 band equalizer at a resale shop for $5. It had a stupid interface, a pin header, which will require some research with the mouser catelog and a dial caliper to figure out. Or rewiring with a RCA jack panel, available from Switchcraft. An 8 jack panel is $6 plus freight.
I actually bought a stereo 12 band equalizer at a resale shop for $5. It had a stupid interface, a pin header, which will require some research with the mouser catelog and a dial caliper to figure out. Or rewiring with a RCA jack panel, available from Switchcraft. An 8 jack panel is $6 plus freight.
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What is sq?
some are noisier than others, some distort more than others, most have too much hum due to age and old power supply caps. At these prices it is a **** shoot what you get. I took a ****y $15 disco mixer and turned it into a pretty good sounding record player preamp with about $25 in parts. The disco mixer was so bad as packaged, the slide pots were perfect, ie unused. Decent circuit board design, stupid packaging with the power transformer and switch 1" from the high gain magnetic phone circuits. I took the transformer out of the steel box entirely, and upgraded the op amps, and tweaked the power supply to eliminate oscillation of faster quieter op amps.
The noisier of the equalizers may have similar tricks you can do to improve them. Spend L5 and give us a schematic of what you've got, we'll make specific comments. Besides the given, old electrolytic caps are beer cans sealed with dirt (old rubber).
One caveat. Some manufacturers, like Behringer and Numark, won't let you see the schematic diagram, make the servicemen sign legal agreements before they can see them. Other manufacturers like Peavey give schematics away online. If you see a brand of used equalizer in a shop check for schematics online before you buy it.
Also the newer the device, the more likely it is to have crimped connectors requiring special tooling to repair, or surface mount parts requiring $1000 in tooling to remove and replace. Anything that is ROHS compliant, for example, requires at least a $100 soldering iron for silver solder, not a $40 iron like I use on tin lead solder on equipment that is not ROHS compliant.
some are noisier than others, some distort more than others, most have too much hum due to age and old power supply caps. At these prices it is a **** shoot what you get. I took a ****y $15 disco mixer and turned it into a pretty good sounding record player preamp with about $25 in parts. The disco mixer was so bad as packaged, the slide pots were perfect, ie unused. Decent circuit board design, stupid packaging with the power transformer and switch 1" from the high gain magnetic phone circuits. I took the transformer out of the steel box entirely, and upgraded the op amps, and tweaked the power supply to eliminate oscillation of faster quieter op amps.
The noisier of the equalizers may have similar tricks you can do to improve them. Spend L5 and give us a schematic of what you've got, we'll make specific comments. Besides the given, old electrolytic caps are beer cans sealed with dirt (old rubber).
One caveat. Some manufacturers, like Behringer and Numark, won't let you see the schematic diagram, make the servicemen sign legal agreements before they can see them. Other manufacturers like Peavey give schematics away online. If you see a brand of used equalizer in a shop check for schematics online before you buy it.
Also the newer the device, the more likely it is to have crimped connectors requiring special tooling to repair, or surface mount parts requiring $1000 in tooling to remove and replace. Anything that is ROHS compliant, for example, requires at least a $100 soldering iron for silver solder, not a $40 iron like I use on tin lead solder on equipment that is not ROHS compliant.
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