2. analog
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Help deciding which TT

A little background.

I currently have a Rega RP1 w/Ortofon 2M Blue. It seemed great until I added a subwoofer. The sub is exhibiting woofer pumping when attempting to play vinyl. The problem even occurs if I place the needle on a record without the motor running, and then increase the volume. As the volume increases (again, the patter is not moving), the subwoofer (Martin Logan Grotto I) will start to pump. Eventually the sound becomes audible.

That IMO eliminated any motor, or bearing issues.

I've moved my TT to a wall shelf which seemed to have greatly reduced the pumping, but it's still present. I'm at the point where I'm thinking about purchasing a higher quality table. Here are some options I'm considering.

1) Brand new Clearaudio Concept w/ Clearaudio MM $1600
2) Demo Rega RP6 w/Exact Cart (full warranty) $1500
3) Lightly Use VPI Scout JR w/Ortofon 2M Black $1300
4) Used VPI Traveler V2 w/2M Black (200 hrs) $1000

I understand that I may have still have the same issue, but I'm hoping a better table will reduce/eliminate the issue. Any thoughts on the above tables?

Thanks
mustangjeff
noromance's avatar
noromance
9,840 posts
 
It is acoustic feedback from the sub into the turntable body...bearing...platter...stylus. Put a slab of granite under the TT on the wall shelf.
zd542
5,339 posts
 
"The subwoofer is connected to my Anthem MRX HT receiver via LFE connector. No issues with digital sources of course. My phono preamp is a Rega Mini Fono A2D."

You should only use 1 LFE connection. If you connect IC's to the LFE out on your HT preamp, the other end should go to the line level input on your sub, not the LFE input. Try that first.

You may also want to try lowering the gain on your phono preamp, as well as checking the gain on the channel you are plugging it into. A lot of theatre processors have that ability. Also, I'm assuming that you are using the analog connections on your phono pre, and not the USB option.
mustangjeff OP
30 posts
 
"It is acoustic feedback from the sub into the turntable body...bearing...platter...stylus. Put a slab of granite under the TT on the wall shelf."

I have a 30lb two inch thick slab of Maple between the wall shelf and the Rega. The rega sits on top of four Herbies tenderfeet instead of it's normal three stock feet.

The Martin Logan Grotto i subwoofer is the only thing connected to the LFE output on the receiver. The phono preamp is connected to the receivers analog (AUX) input. The only time I've ever used the USB is to connect the preamp to a computer for recording.

I don't think the Rega Mini Fono has the ability to lower the gain on the analog connections. I think the gain control only works with the usb port.
zd542
5,339 posts
 
"I don't think the Rega Mini Fono has the ability to lower the gain on the analog connections. I think the gain control only works with the usb port."

You can sometimes control each input on a HT preamp individually. I keep coming back to this gain issue because 5.5 MV seems pretty high. I haven't uses a MM cart in years, so I guess that could be normal for them. The highest output cart I can remember having is a DV 10x5 at 2.5 MV, and you needed to set the phono pre on MM to use it.

Maybe try fooling with the xover on the sub. See if you can set it to have a limit on how low it will go. It may be having a difficult time with really low notes, and that distortion is somehow effecting the system. Also, it wouldn't be a bad idea to try connecting the sub normally, without using the lfe, and any other type of EQ/Room Control processing.
banerjba
82 posts
 
Any possibility to add a subsonic filter? Lots of budget phono Pre amps have them too.
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