Uturn audio-no sound

[aragorn723]

Interesting thing happened this morning.  Got the Grado Black back on, and set the tracking force to 1.5 per theanufacturer's recommendation (it was at 2.05 when I got the record player).  That really opened up the sound of the treble and mids!  I love this hobby, a little tinkering is always worth it IMHO.  Learned something new too.

Dave

[aragorn723]

Got the London cartridge working tonight!  The mounting bracket separates from the cartridge, and there are pins on the mounting bracket that line up with tabs on the cart.  Bent one tab back a little because it wasn't making connection for the ground.  I have both channels, but can't really listen to it yet.  Highs are a little sharp, mids are recessed, and no bass.  The distributor says it needs 50 hours burn in.  Does this sound like I just need a burn in, or is something else going on?

Dave

[Paul Birkeland]

It sounds like you need to adjust VTA.

[galyons]

The London Maroon has a spherical stylus. Not very sensitive to VTA. New cartridges need a break-in period.

Cheers,
Geary

[aragorn723]

Still working on this cartridge, and the vocals have come in.  Turns out the London Maroon has a common ground, so only 1 ground wire can be connected.  It plays music, but I'm getting a bad hum.  Did a little experiment and ran a temporary ground wire from the phono preamp and held it it place on the tonearm.  That substantially decreased the hum I've been hearing.  How can I permanently hook up this ground?  Seems like leaving a wire directly attached to the tonearm could affect the arm's tracking.  Not sure if I mentioned it, but the turntable is a Uturn orbit. 

Dave

[Paul Birkeland]

Is there no earthing screw on the TT by the RCA jacks?

[aragorn723]

Unfortunately no, Uturn grounds internally.

Dave

[Paul Birkeland]

You may be able to lift the earthing connection in the little box on the TT with the RCA jacks, then feed that out to an external earthing wire/post.

This is how turntables were for decades before manufacturers tried to simplify them.

[galyons]

Are you not using the 4 pin sled that comes with the Maroon?  That ties the ground to the 4 pin wiring schema of modern cartridges and tonearms.  That should eliminate the need for additional wires, (better known as ground loops).  with everything wired as directed, check for continuity of ground and signal at the RCA jacks.

[aragorn723]

I'm using the 4 pin bracket.  The grounds are tied together for the middle 2 pins.  It seems like I'm getting closer to getting this thing playing, but it has been a journey.  Right now the only time I get hum is when the phono preamp is switched on.  The London uses a common ground, so I'm wondering if that is the issue, maybe it's not grounding well to the phono preamp?(Uturn audio uses an internal ground from the left rca cable iirc). 

Not sure i'm understanding the continuity test, so you're saying to disconnect the rcas from the jack and check continuity from there to each of the cartridge pins?

Dave