[DecibleDude]

 I've just set up my 120 but can't figure out which is the right and left channel on the amp since they're not labeled. So I have the top two going to the left speaker and the bottom two going to the right but don't know if they're backwards or not? The second question is about the ground switch on the back. The instructions recommend starting with the switch off and then if there is hum switching it on but I hear no hum either way it's pretty much dead silent regardless. Anyway, I don't see any third prong on either the tuner or cd player so I switched the SET120 ground to on. Is that the right setting if the two items I have connected to the set have no third prong?

[opnly bafld]

The speaker fuses indicate L & R.
Ground lift switch off if no hum, that is why it is recommended to start with it off.

[DecibleDude]

Yeah, thanks, I finally noticed that the fuses were labeled  and so figured it out. I still find the hum switch odd though because the amp is dead silent (a good thing) no matter which way the switch is. The reason I turned it on is because neither my cd player or tuner have a third prong so I assumed having the set 120 chassis grounded would be a good thing. I'll have to try calling them tomorrow about that and because I have a couple of other questions about the unit I'd like answered as well. Having said that, the amp sounds beautiful, actually shockingly so, and with the silver face plate its quite attractive.   

[AVASupport]

Hi DecibleDude,

If you do not have a ground loop hum, you do want to have the ground lift switch in the on position. Here is the explanation from the user manual:


The Vision SET 120 is equipped with a polarized IEC AC power socket designed to accept a standard three conductor AC power cord. The Vision SET 120 chassis is always “earthed” (connected to your electrical system earth ground) through the center pin of the IEC power socket. Because having multiple component audio grounds connected to earth through their IEC power jacks may cause ground loop hum or buzz to occur, the Chassis Ground switch is provided to eliminate this possibility.

When the “CHASSIS GROUND” switch on the back panel is in the ON position, the audio circuit ground is connected to the chassis—and thereby to earth. When the switch is in the OFF position, the audio circuit ground is disconnected from the chassis and so no direct connection between the audio circuit ground to earth is made.

We recommend starting with the CHASSIS GROUND switch in the ON position. If you hear a hum or buzz try turning off the switch.

[DecibleDude]

My booklet says, "We recommend starting with the chassis ground switch in the OFF position. If you hear a hum or buzz try turning on the chassis ground switch."

[TomBo]

Could someone from AVA please clarify if the ground switch should be on or off if I have no electrical buzzing? I too assumed to operate with the switch set to off...  TY !  Loving my SET 120 Controller! It's magical!  Been running it from the 1/8th inch mini plug headphone outlet from the TV with phenomenal results and can use the TV remote to control the volume....  . 

[AVASupport]

Just to clarify.....

The SET 120 Control amplifier the ground switch should be in the OFF position unless you are having a hum (ground loop) issue.

The SET 120 basic amplifier, M225 mono amplifiers, SET 500, and M750's should have the switch in the ON position.

All of the user manuals will tell you this information, specific to each product.