question re: grounding issues with crappy turntable

[Questionable Productions]

i'm having a problem with my piece of shit turntable.
(i say p.o.s. because it really is, i spent only $80 as i never planned on using it)
basically its like this
i've got a digi002 rack going into an emac g4.
turntables are using rca inputs --> alt src and alt src --> in 7-8.
the turntables have one of those ground lifts that you screw the horseshoe connector into. i have this grounded to the wall and the buzz went away.
i have a pacific pro audio oxford 911 harddrive going into a firewire port on the emac.

now, when recording turntables through pro tools, there is a low rumbling noise that plops in every few moments that just happens to be at the exact moment the external harddrive lights up its little LED's signifying disk writing.
what does this mean?
i am at a loss on this one, so any ideas would be really helpful.

thanks a lot.

[Professor]

Are the turntable and hard drive on the same table? It could be as simple as a mechanical jolt when the hard drive starts spinning that is picked up by the turntable. It may be that or it may be something electrical, but I'd check the mechanical first by just moving the hard drive off your desk.
If it's electrical, or somehow related to the 002 and the drive both hanging on the firewire port, then that will be harder to find. It probably wouldn't have anything to do with the wall outlet grounding point, though for the sake of ease, you could probably move that connection up to the little silver screw next to the ALT-SRC RCA connections on the 002. Though that brings up another issue... you're not hitting a phono preamp.
Turntables need to be plugged into phono preamps which perform a couple of important tasks including loading the cartridge properly, adding some extra gain, and applying the RIAA EQ curve to correct for the amplication of that curve when the record was pressed. Unless your turntable is sending out a line-level output (meaning it has a built-in preamp) then this is kind of important.
I don't recall the exact numbers, but I'm sure someone else will fill 'em in. In order to reduce the chances of a loud, low-frequency sound from tossing the needle out of the groove, and in order to reduce the effects of the surface noise on playback, two EQ settings are placed on records, a big drop in the bass and a big bump in the highs. In a phono-preamp, those are reversed to pull the bass back up to normal and pull the highs down to normal, while also pulling the surface noise down along the way.
Of course, adding the phono preamp may increase the low frequency issue if it is mechanical (because of the boost to the bass) but it may also reduce it if it is electrical because you will be hitting the 002 with a stronger, line-level signal.

That probably just caused more confusion - but hopefully it'll get you started.

-Jeremy

[tactics]

Try running the turn table through a cassette deck first otherwise the signal might be too low.I've done this exact process on from an old stereo into Mbox line ins.Put the cassete deck in "record/pause" and take cassete deck output to 002 inputs.Adjust tape deck level input for more or less signal.

Phono->Amplifier->Cassette deck->Mbox line inputs.

[Questionable Productions]

right on guys, thanks for the suggestions.

i realize now i forgot to mention that my first attempt at correcting this problem involved buying longer cables so i could move the turntables far away from the harddrive.
but to no avail.

the phono preamp suggestion is right on.
i know i am missing this but lately i've just been throwin my own eq curve on there that i feel is close to what the built-in eq's accomplish in said devices.
but you're right, it isn't the same and i should definitely buy a phono pre.
how much would that run me?

i would go with the cassette deck fix as suggested but i honestly don't have one..
i suppose i could hit up the goodwill or somethin though..

but after all that i still have that noise, right?
so.. shit.

thanks for the help though.

[kayagum]

Rolls makes one for $50-$60 street.

http://www.zzounds.com/item--RLLVP29

If you want to get esoteric, most high-end stereo shop sell them.

Oh, some Spirit mixing boards have RIAA inputs.

[Professor]

Or for a dirt cheap alternative, you might hit up goodwill or a similar place for an old hifi receiver. $10-20 for a 1980s vintage home stereo receiver with a phono input and a tape output would do ya fine.
If the noise is related to the firewire input, then hitting the ALT SRC at phono level and then boosting the bass inside the DAW with your own EQ curve will accentuate the problem. If you're instead hitting the input with line-level, post EQ, then that little thump may be way too low to be heard. You can test it by running the whole setup with playing an actual disc - just record silence from the turntable but with everything else going. If there is any thump in there, you could use the EQ to reduce it instead of using the EQ to bump up the bass.

-Jeremy

[Questionable Productions]

ok, ok.. all good input.

i've recorded the turntable without anything playing and without any eq whatsoever and the thump is still quite noticeable. it seems to be a very broad range of frequencies, as i've tried eq'ing just the thump and found that i'm losing way too many frequencies i need..
in any case, i'm definitely going to be hittin up all the goodwill/value-type stores in the neighborhood to find a hi-fi receiver.
but i'm still worried about the thump.
i really need to lose the thump.

[Professor]

Hey a sudden thought... is the firewire drive drawing power from the firewire bus or from a wall outlet? If it's drawing power from the bus, then there would be a sudden drop in the power on the line where the 002 is concerned and I suppose that could be the reason for the thump. Maybe. If so, then plug the drive into the wall and see if that helps.

-Jeremy

[Questionable Productions]

ah yes, a valiant effort in your wise thought, but alas the peripheral is in fact powered through a wall outlet, not the firewire bus.

shucks..

this might just be one of those things..

[Professor]

Well, in that case, try the other way 'round.

Hard to say without hearing & seeing the problem and the gear.

But let us know if it ever gets fixed.

-J