2. amps-preamps
  3. 142214-112817

Am I asking too much?

I've spent the last three days chasing a ground loop/hiss issue.  I have unplugged and replugged every combination possible, have tried different type of grounds to phono stage, tried different phono stages, different lines into the amp, different turntables and still when I crank the volume with nothing playing, have this hiss.  At lower volumes I don't hear it, but if I turn it up, it's there.  I probably would never listen that loud, but still worry that at base levels the sound is compromised.  I've had this system connected for a month and don't know if the hiss was always there, or if, when I had to rearrange and reconnect due to Christmas and the wife factor, something changed.

My system is a Line Magnetic LM216IA tube amp, a Heed phono stage, a Rega Planar 3 TT (which doesn't have a ground wire) which plays to Audio Physic bookshelves and a JL Audio e110 sub. One of my biggest concerns has been the lack of ground with the Planar 3.

My system is plugged into a Torus Power Conditioner, so I thing I have that base covered into a dedicated line.  With all these electrical precautions am I expecting too much asking for a black speaker background?

Will be interested to hear similar ground loop stories or thoughts on whether there are other issues that I haven't considered.

udog
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twoleftears's avatar
twoleftears
1,457 posts
 

Yes, first of all is it a hum or a hiss?  A low mmmmmm sound or a slightly higher shshshshshsh sound?

Try disconnecting (completely) first your turntable, then the phono stage. Does the amp+speakers still hum/hiss. Also disconnect the sub. One at a time. Try all the other things suggested too. It’s a slow process of elimination. Hopefully, you’ll find the problem. OR, one or more tubes may be noisy and as also suggested, it may be inherent to the system as it stands.

michaellent's avatar
michaellent
23 posts
 
https://forum.audiogon.com/discussions/rb300-tonearm-cable-upgrade?highlight=Rega%2Bplanar%2B3%2Bgro
Try this post
cakyol's avatar
cakyol
112 posts
 
Use a Jensen audio isolator transformer for HUM ONLY: http://www.jensen-transformers.com/transformers/

Hiss is the noise floor of the electronic components.  U cannot get rid of it unless u have tone controls are you are ok with turning the treble down.  And that will help only so much.


udog OP
15 posts
 
Thanks for all the comments and help.  With your assistance and more experimentation, it is pretty clear that what I have is hiss and not a hum.  I guess it is an amp related problem caused by tubes. Not sure where to go from here or whether it is something I have had and never noticed or if it can be rectified.
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