Korg Poly-800 II has a 60 hz hum ... HELP!

[Synthpopalooza]

Hey guys ...

here's the deal: I have a Korg Poly-800 II analog synth, and it has an intermittent 60 hz hum that comes through the output ... the hum subsides when I move it, then sometimes will come on and off intermittently. Can anybody give me some hardware tips on how to fix this problem?

[~cliffwalk]

Originally posted by Synthpopalooza
Hey guys ...

here's the deal: I have a Korg Poly-800 II analog synth, and it has an intermittent 60 hz hum that comes through the output ... the hum subsides when I move it, then sometimes will come on and off intermittently. Can anybody give me some hardware tips on how to fix this problem?

not to get too geeky but is 60hz just the fundamental or is it hitting the harmonic series (120, 240, 360, etc)?

are you using old cables?

without replacing what's probably becoming really really bad shielding you may want to try some sort of targeted power conditioner.

personally I'd just run all of the tracks through sound forge and notch it around 60 hz until it goes away but you may lose some serious resonance.

dave

[~David Vesel]

Sound for all the world like a bad ground.

I would pop it open and make sure everything is anchored down correctly. The 60 Hz hum is a dead giveaway that it's ground.

[Synthpopalooza]

That's what I was thinking, maybe something's not grounded properly. Now, I will have you know, I am a total idiot when it comes to electrical wiring ... so what all would I be looking for when I pop open the poly-800, and then would I need to do any soldering to fix it?

The hum is so loud and noticeale, that fixing it with Sound Forge is not an option at all.

[~cliffwalk]

Originally posted by Synthpopalooza
The hum is so loud and noticeale, that fixing it with Sound Forge is not an option at all.

OK, if you're getting that kind of amplitude out of the hum then you probably just have old wiring near or around where the main outs are. A Poly 800... that's what, circa Early 80s? So we are talking about solder connections that are 20+ years old and probably dried, cracked shielding.

If you aren't experiencing at replacing that sort of stuff you may want to see if you can find somewhere local that will do it for you. (Used music equipment store?)

I would only attempt it on gear >>I<< own and only if it was my last resort (because I'm not so great with a soldering iron).

Be careful!

This is why I use soft synths... I wouldn't have the patience.

Dave

[~arronc]

OK this one is easy :

The poly 800 can take batteries. Put some in. If it stops hummming, It cant be an internal problem.

The 800 II uses an external PSU in the UK. If it the same age as the synth, its probably burnt out by now, so throw it away and buy a new regulated supply.

But by the sound of it the problem is more likely to be with your mixer.

I bet it is an anolgue mixer with the gain turned up too high ?

SOunds like impedence matching to me from your description.

Get a four way power block, disconnect the earth from the input plu, and plug the mixer into that.

be aware it might kill you if the mixer shorts out though : LOL

[Synthpopalooza]

I am fairly sure it is the poly-800 ... none of my other synths produce the hum, and I have 3 of them currently plugged in: a Yamaha DX-100, a Kawai K1-II, and the Poly-800 II.

Thanks for the advice on soldering ... I am not good at it, but I think my uncle can help ... he helped rescue my Yamaha DX-100 awhile back with a soldering iron. :)