preamp making hum through speakers! help

[scpunk81]

hi i got a preamp for my record player cause my receiver doesn't have a phono input which means no pre amplification right? So when i connect it there is a hum more noticibly through the subwoofer. I tried grounding it to just about everything. I'm stuck now and out of ideas, if anyone can help me I would greatly appriciate it.


if this helps the preamp is a mcm 40-630






thanx

[Mr Peabody]

Is the phono preamp plugged into a regular input? It should be, DO NOT PLUG IT INTO THE "PHONO" INPUT. What type of cartridge do you have, MM, MC, for God sakes I hope not ceramic? Is your ground wire from the turntable connected to the ground screw on the phono preamp? If the turntable has a ground wire it is probably MM or MC. If it doesn't it is either a Rega or a ceramic, which if ceramic, you should throw it away.

If none of the above helps, try a cheater plug on the sub or phono stage to see if it eliminates a ground loop. Other than that, I'm not sure, you might try to borrow another phono stage to see what that does. If the other phono stage is alright, then you know there is a problem with the phono stage or it's compatibility. If you have the same problem with another brand, then further tracking will be required. If you turn the sub off does the hum come through your mains? If the phono stage and sub are close, you could see if moving them apart more does anything.

Good luck, I know these problems can drive one crazy.

[Mr Peabody]

PS, I see you have a Gemini XL100. I tried to do some research but didn't find out much info. It does mention some type of pad which I'm assuming is some type of DJ switch. The table also came with the cart but it didn't say what kind. If what I suggested don't eliminate the problem see if you can borrow another turntable to see if that does away with it. If so, you may need to get another table. Don't shoot the messenger but the DJ forums did not speak favorable of this table. You can get a pretty decent rig from Music Hall or ProJect for around $299.00. If that's too much, you might look into a used TT.

That pad could be a source of allowing noise into your system. Give me some feedback on some of this.

[JohnMichael]

If your turntable is too close to the subwoofer or not isolated well you may have acoustic feedback from the low bass. The bass will feedback through the cartridge and be reamplified and create more hum. Of course this only happens when you are playing a record. If it hums all the time then it is electrical in nature and not acoustical.