why does my soundcard hum?

it sounds like one of two things..

motor transmitting at vhf frequency, or as you say, stylus picking up vibration.

those project decks are pretty spanky... maybe take it back to the shop and explain your issue.. the platter should be isolated from any motor vibration, and if it's not, you got sold a bum deal.

so you don't get the buzz when there's no power to the deck, and if you cut the power, the frequency drops, preumably parabolically?

shielded cables might still help.

other than that, i got buttkiss. sorry.

i just read the motor relation. friend of mine tried to solve a similar problem and in the end he exchanged the decks.

edit: the shielded cables sadly won't exchange the possibly bad isolated cables within your deck. and to me it seems like thats the problem. mostly related to cheap production, but sadly these days you cannot relate anything to the price of a product.

stupid question, and almost definitely unrelated, but you have earthed your deck, right?

  loganfive said:

so you don't get the buzz when there's no power to the deck, and if you cut the power, the frequency drops, preumably parabolically?

Yeah, that's exactly it. As soon as it's turned off the spectral view of the hum pretty much like this:

  loganfive said:

stupid question, and almost definitely unrelated, but you have earthed your deck, right?

Yeah, it's been fully earthed using the brounding wire from the deck to the eath socket to the pre-amp. But don't worry, that would be my first suggestion too !

can you borrow a mates deck and try it through the same signal chain?

if the problem is eliminated, it's time to take the deck back to the shop.

Huzzah, it's fixed. It turned out that the surface that the table was on wasn't 100% flat which caused the motor to not be completely decoupled from the deck (the motor of the debut sort of dangles down a hole in the casing but in this case it was vibrating against the chassis). A quick propping up with an old copy of Edge magazine made it work again like a charm !

Cheers for everyone's suggestions though !

dang.

  mcbpete said:

Huzzah, it's fixed. It turned out that the surface that the table was on wasn't 100% flat which caused the motor to not be completely decoupled from the deck (the motor of the debut sort of dangles down a hole in the casing but in this case it was vibrating against the chassis). A quick propping up with an old copy of Edge magazine made it work again like a charm !

 

Cheers for everyone's suggestions though !

you should have used a new copy. those old ones are actually still worth reading! but, creativity 9/10! non-signed integer, that is.

  mcbpete said:

Huzzah, it's fixed. It turned out that the surface that the table was on wasn't 100% flat which caused the motor to not be completely decoupled from the deck (the motor of the debut sort of dangles down a hole in the casing but in this case it was vibrating against the chassis). A quick propping up with an old copy of Edge magazine made it work again like a charm !

 

Cheers for everyone's suggestions though !

UPDATE: This 'solution' seemed to fix it for a few uses and it's now back to it's usual hummy ways. I'm currently having to run everything through Cool Edit - Scientific Filter -> 99-101 HZ attenuation which does completely remove the hum (and still retains the 100hz segment of a track), but it's a bit of a shit all the same. I'm really thinking it's something to do with the motor as it vibrates quite a bit when you put your finger on it.

i had this problem too

ground lifter

totally works for me

would i stick the ground lift isolator between the turntable and preamp or the preamp and the soundcard ?

Plus would there be any reason why the hum only exists when the stylus is in contact with the vinyl, and also only seemily audible on 45 rpm.

  mcbpete said:

would i stick the ground lift isolator between the turntable and preamp or the preamp and the soundcard ?

probably between the preamp and the card.

  mcbpete said:

Plus would there be any reason why the hum only exists when the stylus is in contact with the vinyl, and also only seemily audible on 45 rpm.

pfft. fucked if i know mate.

got me truly stumped. not sure if a ground lift will help. it might.

I had this same problem... All you gotta do is get one of those 3 prong -> 2 prong plug adapters and your noise will completely go away. This problem was driving me nuts for months until I read that on an audio forum.

Hmm, what are these 3 prong -> 2 prong adaptors of which thou speak ? Surely a 2 prong plug wouldn't fit in a UK plug socket (plus losing the earth pin sounds kinda dangerous)

Here's another spectral view of the noise, notice that when I switch the speed of the deck to 45 the 100Hz line vanishes (although there appears to be another tone ~130 Hz in the left channel (see top part of graph), though this is for all intents and purposes inaudible) and then reappears when I switch back down to 33. Ignore the vertical lines running all the way though, it's just because I've left the player in the run out groove.

  mcbpete said:

Hmm, what are these 3 prong -> 2 prong adaptors of which thou speak ? Surely a 2 prong plug wouldn't fit in a UK plug socket (plus losing the earth pin sounds kinda dangerous)

 

Here's another spectral view of the noise, notice that when I switch the speed of the deck to 45 the 100Hz line vanishes (although there appears to be another tone ~130 Hz in the left channel (see top part of graph), though this is for all intents and purposes inaudible) and then reappears when I switch back down to 33. Ignore the vertical lines running all the way though, it's just because I've left the player in the run out groove.

 

well shit... i only know how stuff works here in the greatest cuntry on erf... USA ALL THE WAY! :alien:

  brianellis said:

  mcbpete said:

Hmm, what are these 3 prong -> 2 prong adaptors of which thou speak ? Surely a 2 prong plug wouldn't fit in a UK plug socket (plus losing the earth pin sounds kinda dangerous)

 

Here's another spectral view of the noise, notice that when I switch the speed of the deck to 45 the 100Hz line vanishes (although there appears to be another tone ~130 Hz in the left channel (see top part of graph), though this is for all intents and purposes inaudible) and then reappears when I switch back down to 33. Ignore the vertical lines running all the way though, it's just because I've left the player in the run out groove.

 

 

well shit... i only know how stuff works here in the greatest cuntry on erf... USA ALL THE WAY! :alien:

I'll second that. Who's ever heard of laptops and turntables with grounding pins, anyway? Just because some highfalutin commission says every electrical appliance needs to be grounded doesn't make it a fact. Just snap that shit off.