Mu metal for Brio Integratdd


Hello All

Last year I bought latest version Rega Brio integrated. I paid 300$ and I’m very pleased on how it powers my Tekton speakers. One issue though. Hummmmmm. I confirmed through audio tech and searching forums the small 1/2 size chassis contributes to this issue. I tried several recommendations for confirming it’s not ground loop issue or issue with house wiring or from other components…..I was tempted to purchase some MU metal and enclose the top and sides of the toroidal transformer. Has any one attempted this on the Rega integrated or other amps? Did it address the problem? Any advice on doing this mod?

pdspecl

I would look at how your equipment is tied to the electrical grid.  Odds are it is leakage from the AC line to chassis to interconnect shields.  If you have one power cord it won't matter but if you have two it is guaranteed you have a ground loop.  Have a power cord with three prongs and you have a bigger ground loop.  UL is great for not getting shocked but they are very unkind to high end audio - their excessive leakage limits really screw things up.

Trying to fix hum leakage with shielding is expensive and marginal at best.  The reason is you are treating symptoms and not the cause.  The beat approach is to separate the transformer from the electronics physically with distance but if the transformer is internal, that isn't possible.  Distance cures the hum radiation field, but there should be very little radiation with a torridal transformer.

You might try a medical grade isolation transformer between the wall outlet and  your system, then make sure all earth grounds tie to one spot and only one spot.  If you have equipment with two prong power cords, connect a ground wire from the chassis to the common earth ground.  That will cure the leakage problem.

I tried most of what was suggested.   I also removed all components except the Brio integrated amp.    Still have the hum.    I’ve had many other combinations of components in the same room and never had a problem.  Tube amps, solid state amps…. All kinds of gear and different configurations. No issues until I got this Rega.   Also I checked and it appears other owners noted the same issue with their units.   

You bought a $1K amp for $300, so sounds like you picked up a used unit. Have you considered the possibility that it needs service? Could be a bad capacitor, a bad internal connection, or some other problem that needs professional technical service.