aragorn723
New member
I just changed the cartridge on my Uturn Orbit, and now don't have any sound at all with the new cartridge. Only sound is a loud humming sound. What could be wrong?
Dave
Dave
Uturn audio-no sound
- Thread starter aragorn723
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Thermioniclife
Member
Is there a ground wire connected the phono preamp. Terrible buzz is an indication of a poor or no ground.
aragorn723
New member
There is no ground wire from the Uturn to the phono preamp , it's internally grounded. I'm wondering if maybe the cartridge wires aren't hooked up right? The London cartridge has color coding on the pins.
Red-right channel positive
Green-right channel negative
White-left channel positive
Blue-left channel negative
The wires from the Uturn had these colors, so I just matched red to red, blue to blue, etc. Maybe Uturn is using a non-standard color scheme?
Dave
Red-right channel positive
Green-right channel negative
White-left channel positive
Blue-left channel negative
The wires from the Uturn had these colors, so I just matched red to red, blue to blue, etc. Maybe Uturn is using a non-standard color scheme?
Dave
Thermioniclife
Member
I am not familiar with that cartridge but you need a good ground to the pre. does the cart mounting tabs have a conductive pad on them? If so you can try a small gauge wire connected to one of the cart mounting screws to the phono pre as a test. It's been decades since I have had a turn table and vinyl. Perhaps you could call the manufacturer for advise.
galyons
New member
Decca cartridges are more than a bit quirky. I think they are very poor choice, and/or recommendation, for vinyl newbies. They literally have almost no suspension, are not easy to align properly and are very easily fatally damaged. (Don't ask me how I know!)
The original design is ancient. It is a three wire layout. The L & R channels share a common ground. The actual cartridge is shoved into a rather rough plastic carrier mount that ties the grounds to the common 4 pin configuration. Sometimes it works. Sometimes....
I would go to the Lenco Heaven forum cartridges section and look for Decca threads. It is the best source of community knowledge on these cartridges.
Cheers,
Geary
The original design is ancient. It is a three wire layout. The L & R channels share a common ground. The actual cartridge is shoved into a rather rough plastic carrier mount that ties the grounds to the common 4 pin configuration. Sometimes it works. Sometimes....
I would go to the Lenco Heaven forum cartridges section and look for Decca threads. It is the best source of community knowledge on these cartridges.
Cheers,
Geary
aragorn723
New member
Thanks all. Gonna start with Uturn. Was hoping there was something simple I overlooked, but maybe they can help troubleshoot the issue on the turntable side. The London distributor has been very responsive too, so that might be a good option also. Hopefully it's not the cartridge.
Dave
Dave
Adrian
New member
I used to have a Rega TT and they do not have an external ground wire.
Here is what I found on their ground connection:
"Rega grounds the tone arm tube to the phono preamp using the shield of the left channel of the phono interconnect cable. It might be the connection of the outer shell contact of the IC to the RCA jack on the phono preamp maybe corroded and not making a good low resistance connection. You might try unplugging both the L and R channel ICs from the phono preamp jacks and plugging them back in repeating the process several times. That should clean the connections.
If that doesn't help you could install a small gauge stranded insulated ground wire from the TT tone arm to plinth support nut on the under side of the TT and connect the other end of the ground wire to the ground lug on the phono preamp."
Maybe this will help.
Here is what I found on their ground connection:
"Rega grounds the tone arm tube to the phono preamp using the shield of the left channel of the phono interconnect cable. It might be the connection of the outer shell contact of the IC to the RCA jack on the phono preamp maybe corroded and not making a good low resistance connection. You might try unplugging both the L and R channel ICs from the phono preamp jacks and plugging them back in repeating the process several times. That should clean the connections.
If that doesn't help you could install a small gauge stranded insulated ground wire from the TT tone arm to plinth support nut on the under side of the TT and connect the other end of the ground wire to the ground lug on the phono preamp."
Maybe this will help.
aragorn723
New member
I just realized there is something I forgot to mention. When a record is placed on the turntable and the stylus is lowered, there is some sound. If you place your ear very close to the cart some sound is audible. Maybe there is a gain issue in addition to the ground? Did some research on my phono stage too, and there is a level control (normally I don't see this as the phono stage is tucked out of sight). I'm wondering if maybe the cart is working after all?
Dave
Dave
aragorn723
New member
Gotcha. Always wondered what that sound was. Uturn emailed back and wants pictures. They are determined to figure this out. Everybody loves a good problem to solve, on wait no, that's just engineers lol.
Dave
Dave
aragorn723
New member
Just played with the volume knob, no change in music output regardless of position. Hopefully Uturn can figure it out.
Dave
Dave
aragorn723
New member
The verdict from Uturn is the turntable is fine, but something is wrong with the cartridge. Waiting to hear from the distributor in the UK to see what to do next, think I can hook up my old cartridge for some weekend listening? Thinking this will be a RMA situation.
Dave
Dave
Yes, put your old cart back on.
aragorn723
New member
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
Dave
aragorn723
New member
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
Dave
It sounds like you need to adjust VTA.
aragorn723
New member
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
Dave
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