[Mrtn77]

  I would place a solid base underneath the table for isolation if you haven't already.

 
Do you mean this as general advice or as an answer to my nerve-wracking hum problem ?
Ignorant as I am, I'd be keen to know how a solid base would help. My previous table was sat on the same surface (a Canon printer, alas) and behaved perfectly. It did, however, seem a lot more "robust" than the project does. 

 

[bbophead]

Could be a loose connection causing an intermittent situation.  Make sure both the Pro-Ject and the Rega are connected securely, maybe pop the top on the Rega (while disconnected from the mains of course), could also be loose at the Pro-Ject end.  Hope this helps.

 

[RUMAY408]

   
Do you mean this as general advice or as an answer to my nerve-wracking hum problem ?
Ignorant as I am, I'd be keen to know how a solid base would help. My previous table was sat on the same surface (a Canon printer, alas) and behaved perfectly. It did, however, seem a lot more "robust" than the project does. 

 
Sounds like a grounding issue which could be from a loose wire connection about anywhere, but I would make sure all the connections from tonearm and cartridge are right along with the ground wire to the amp/receiver.  

 

[Mrtn77]

Thank you both. I'll check things out in the morning (it's a little late for that here). In the meantime, by "popping the top on the rega", do you mean opening the thing's case ? Wouldn't that void the warranty at a time when I may well need to call upon it ?

I'm fairly sure the ground wire is well connected on the table's end (thank you screwdriver), the rega doesn't allow for such a secure fit.

I should perhaps stress that the hum is random (though maddeningly frequent), starts all of a sudden and stops randomly as well. If the table were somehow to blame, wouldn't the hum be continuous ?
As you can probably tell, I'm pretty keen on blaming the preamp !

 

[RUMAY408]

Thank you both. I'll check things out in the morning (it's a little late for that here). In the meantime, by "popping the top on the rega", do you mean opening the thing's case ? Wouldn't that void the warranty at a time when I may well need to call upon it ?

I'm fairly sure the ground wire is well connected on the table's end (thank you screwdriver), the rega doesn't allow for such a secure fit.

I should perhaps stress that the hum is random (though maddeningly frequent), starts all of a sudden and stops randomly as well. If the table were somehow to blame, wouldn't the hum be continuous ?
As you can probably tell, I'm pretty keen on blaming the preamp !

 
Sounds like a loosely connected wire any where between the phono cartridge and the amp.  Usually the hum gets louder by turning up the volume with a disconnected wire.  Intermittent hum suggests an on and off connection, possibly by the vibration while running the TT. 

 

[Destroysall]

   
Do you mean this as general advice or as an answer to my nerve-wracking hum problem ?
Ignorant as I am, I'd be keen to know how a solid base would help. My previous table was sat on the same surface (a Canon printer, alas) and behaved perfectly. It did, however, seem a lot more "robust" than the project does. 

 
Sorry about that, but the hum problem could be solved that way is what I meant. It could be worth trying. A wood base (such as a thick cutting board) could possibly work..

 

[bbophead]

 

   
Do you mean this as general advice or as an answer to my nerve-wracking hum problem ?
Ignorant as I am, I'd be keen to know how a solid base would help. My previous table was sat on the same surface (a Canon printer, alas) and behaved perfectly. It did, however, seem a lot more "robust" than the project does. 

 
Sorry about that, but the hum problem could be solved that way is what I meant. It could be worth trying. A wood base (such as a thick cutting board) could possibly work..

Sorry, man, but that sounds like voodoo.

 

[Skylab]

Actually, it's not necessarily. It is possible to get acoustic feedback from a powerful subwoofer that would cause a loud humming sound that would be intermittent. I had tho problem a long time ago and solved it with an isolation platform. It's not super common, but it would be an intermittent humming type sound.

 

[Destroysall]

That's what my local dealer recommended when I took him my Technics turntable. I am currently using the receiver I plug my turntable into as an isolation method, and while I would prefer a wooden base or something better, it isn't a terrible solution at all.

 

[Mrtn77]

Thanks for clarifying the isolation block theory. I'll give it a try, if all else fails.
 
Further troubleshooting : I tried examining the wires sticking out of the cartridge and everything seemed fine. Haven't found a way to open the table itself, beyond lifting the platter, not sure I'd feel confident enough to try.
 
But I did play around a bit and made the following obversations.
 
I get the intermittent hum with the turntable turned off (plug pulled). Could the hum be a product of faulty isolation if no sound is playing ?
 
I tried removing the ground wire from the Rega. The high-pitched hum seems, perhaps, slightly less frequent (I might be imagining things), but I get a lot of buzz that I did not have before. 
 
Is there anything else I can try ? Both the Rega and the Pro-ject table are still under warranty, if it comes to that.

 

[Skylab]

If you still get hum with the turntable's power disconnected, that would seem to eliminate a grounding issue relative to the TT itself, and also eliminate isolation as the issue. I would now suspect there is some sort of problem in your phono stage.

 

[Mrtn77]

If you still get hum with the turntable's power disconnected, that would seem to eliminate a grounding issue relative to the TT itself, and also eliminate isolation as the issue. I would now suspect there is some sort of problem in your phono stage.

 
Ah. Sorry for being so clueless, but is there anything I could attempt before sending it back to the shop ? I'm not sure I'd feel very confident opening the case if there's a chance it might void teh warranty, given I'm not very handy with machines, however simple they might be.
 
I should also add that the hum stops when I remove the turntable's RCA cables from the preamp.

 

[bbophead]

Sorry, Destroysall, I had forgotten about acoustic feedback although now that doesn't seem to be the problem.  
 
Even though my TT sits on a Target shelf bolted to the studs, I still have to be careful as powerful low bass on a very few records can make the studs vibrate(!) and cause a problem.  Thanks, Skylab, for reminding me.
 
I hope the OP bought from a local dealer.  That would eliminate some back and forth via the mails. 

 

[CH23]

Hello all!
 
after setting up a great portable rig, i'm now trying to upgrade my home setup.
 
at this moment i have a technics SL-7 turntable, and a few Grado headphones (PS-1000, RS-2, GR-10)
i need to upgrade my pre-amp, and am looking for a headphone amp.
 
i'm also looking for a new cartridge, and i think i will simply go for one of the sub $200 grado ones.
 
i think i'd prefer solid state amps, as it's easier to keep them 'neat'
 
anyone got any suggestions?
 
thank you,
CH23

 

[Destroysall]

  I should also add that the hum stops when I remove the turntable's RCA cables from the preamp.

As Skylab as said, it sounds like an issue with the phono preamp then. I would just deal with dealer if you can. Explain to them what happened and see if they will do a replacement for ya.

  Sorry, Destroysall, I had forgotten about acoustic feedback although now that doesn't seem to be the problem.  
 
Even though my TT sits on a Target shelf bolted to the studs, I still have to be careful as powerful low bass on a very few records can make the studs vibrate(!) and cause a problem.  Thanks, Skylab, for reminding me.

Nah, don't apologize. I didn't clarify myself like I should have, so I apologize on my end.

 
On that, the bolts could cause vibration. Of course, that is just my educated guess. Relocating it to a place where vibrations are minimal could possibly help. Not sure how your setup is, but some place away from your speakers would be best.
Quote:

  Hello all!
 
after setting up a great portable rig, i'm now trying to upgrade my home setup.
 
at this moment i have a technics SL-7 turntable, and a few Grado headphones (PS-1000, RS-2, GR-10)
i need to upgrade my pre-amp, and am looking for a headphone amp.
 
i'm also looking for a new cartridge, and i think i will simply go for one of the sub $200 grado ones.
 
i think i'd prefer solid state amps, as it's easier to keep them 'neat'
 
anyone got any suggestions?
 
thank you,
CH23

Hello CH23! The SL-7, based on reviews seems to be a wonderful table! I would check out the manuals via Vinyl Engine (you will need to sign up for a FREE account to view them) to help you determine which cartridge you can use (in terms of weight). I do recommending reading up which Grado cartridge suits you best on websites like Audiokarma and Vinyl Engine. My personal favorite though has always been the Grado Gold1 Prestige. I've heard it before and the music it reproduced was more than amazing.
 
In terms of equipment, what is your budget?