a three wire power cord is a real good idea, too
Mike, WB8VGE SunLight Energy Systems The Heathkit Shop http://www.theheathkitshop.com/ J e e p o|||||||o "If the facts don't fit the theory, change the facts." Albert Einstein On Nov 13, 2010, at 8:26 PM, Richard Knoppow wrote: > > ----- Original Message ----- From: "Joe Loverti" <[email protected]> > To: <[email protected]> > Sent: Saturday, November 13, 2010 4:32 PM > Subject: [Drakelist] My AC-4 is humming just a little. > > >> Hi guys: >> I've rebuilt my AC-4 using the Heathkit Shop Kit recently and all went well. >> All the voltages read within range and I'm happy with the rebuild and the >> kit. >> >> I have the AC-4 mounted inside the MS-4 cabinet and it sits atop my MN2000 >> with brand new rubber feet, yet I can hear a very low AC hum coming from the >> cabinet. It's not coming from the speaker because I can hear the same low >> level AC hum with the speaker cable disconnected. It's not enough to really >> bother me and I only hear it when the room is quiet and the audio from the >> rig is turned down. I'm just wondering if this is normal or do I have an >> issue that I need to take care of. >> >> Any ideas certainly most welcome. Thanks. >> >> Joe >> WW8X >> Miamisburg >> Ohio >> > That kind of hum is often from the transformer. Try tightening the bolts > that hold the laminations together, that may eliminate it. Otherwise you may > have to mount the supply on isolators of some sort like soft rubber grommets > between the transformer and speaker case. There should be gromets or at least > thick washers on the bottom too so that the screws do not make direct > contact. Vibration isolation can be difficult. > > > > > -- > Richard Knoppow > Los Angeles > WB6KBL > [email protected] > > > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist >
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