buzz/hum coming from headphone amp

[Utahguy85]

So when I am listening to a turntable in my office thru a Bravo Audio tube headphone amp there is a constant hum/buzz. It is barely noticeable when music is playing, but when the music is quiet or soft it is always there. I am running a Uturn Orbit turntable to a Rolls phono and then that to the headphone amp. If I use the headphone amp with an iPod there is no buzz/hum to speak of. Any ideas?

Thanks

 

[reydelaplaya]

So when I am listening to a turntable in my office thru a Bravo Audio tube headphone amp there is a constant hum/buzz. It is barely noticeable when music is playing, but when the music is quiet or soft it is always there. I am running a Uturn Orbit turntable to a Rolls phono and then that to the headphone amp. If I use the headphone amp with an iPod there is no buzz/hum to speak of. Any ideas?

Thanks

Welcome to AK.

It sounds as if you have a grounding issue. Where exactly, not sure.

I'd start by making sure the turntable's grounding wire is connected to the Rolls pre securely. If the TT doesn't have a grounding wire, you may solve the problem by adding one.

This post from another thread explains how that would be done:

info on U-Turn Orbit grounding

Below is helpful info I received from U-Turn in response to a question I asked about grounding options for the Orbit TT. I am posting here in case others are interested. FWIW, I really appreciated the manufacturer responding to my questions and providing this technical info! e_identity
--------------------------
Hello,
Thanks for getting in touch. The turntable is grounded internally through one of the audio channels, similar to some high end models like Rega's, among others. Let me know if you have any other questions or concerns.
-------- Original Message --------
[name],
Thank you very much for this prompt and informative response.
I have one additional question.
I understand that the turntable is grounded internally through one of the audio channels.
Is there any provision for connecting an external ground wire to chassis ground on the TT?
Using custom connectors, I will be going out from the RCAs to a balanced in. On the TT end of the custom connector, I would like to connect the shield of the connector to a TT chassis ground. I saw a picture of the board on which the Orbit RCA outs are mounted, and it appeared to show what might (or might not) be a ground screw that I could use for this purpose.
Thanks,
[name]
----------------------------------------
Hello [name],
There is a jumper on the tonearm PCB that allows you to disconnect the channel ground completely. You can then attach a separate ground wire directly off the pin on the PCB. Keep in mind there is no external ground screw so you'll have to remove the metal cover to install your cable.
Hope this helps and let me know if you need any other information!
[name]

After reading that post, that's exactly where I'd start. All you'd need is a length of wire to run from the turntable to the Rolls. No need for anything thick or fancy, just a single lead of 18-20ga would be more than sufficient.

Good luck! Let us know if this works.

 

[woodj]

Ditto.
If the hum gets worse, then regroup.