Bent NOH Grounding Question

Doc Jr 8156 · « **on:** 13 Oct 2004, 03:12 pm »

John,
I recently moved to a new abode and after my NOH was out of service for a week I re-insert it to my system and here is where my problem started. How come when "floating" the ground via the toggle switches on both channels, output to my left speaker greatly diminished? Using "hard ground" made the output to both speakers the same level but hum is present. Swithching the toggle on the left side to "hard ground" and the right side to "float" removed the hum but the left speaker is louder than the right.

I had my NOH for some time and I'm only experiencing this for the first time. NOH owners, any thoughts? Thanks for your inputs. Godspeed.

John Chapman · « **Reply #1 on:** 13 Oct 2004, 03:29 pm »

Hello!

Something goofy going on there! Although many systems don't like the float mode - due usually to sources with no ground connection - most always the hard ground mode will be quiet. Hard ground is basically grounded like a traditional pre-amp - with the input ground connected to the output ground. If you get a hum with hard ground mode it indicates that there is a ground loop in the system - how is the system connected to the wall power compared to how it used to be? Ground loops that would create the level of hum you have are rare - if they were not then any traditional pre-amp (which are all hard grounded) would have issues more often.

The goofy part is that the grounding should have no effect on the levels. You likely have already checked but go back and check all wiring and stuff to make sure it is o.k. ?

Thansk!

John

Doc Jr 8156 · « **Reply #2 on:** 13 Oct 2004, 04:23 pm »

Thanks John. The system was connected (power) as it was before using a Transcendent Balance Power for the sources w/c in turn connected to a Monster HTS 3500 from the wall. I will go back to the wiring again but I already desoldered and resoldered all ground connections from the tranny to all of RCA connectors and the central ground node. I am also dumbfounded by why the output level is affected by the grounding scheme. If ever there's a short somewhere, is it capable of destroying the trannies? Godspeed.

John Chapman · « **Reply #3 on:** 13 Oct 2004, 07:45 pm »

Hello!

You do not need to worry about hurting the transformers. It would take a large dc signal for a prolonged period or a high voltage signal with the secondaries shorted to do any damage. I have nerver had anyone hurt one yet!

Keep me posted and we will get to the bottom of it......

Thanks!

John

Doc Jr 8156 · « **Reply #4 on:** 13 Oct 2004, 09:02 pm »

Thanks John,
I only have RCA inputs, could you please explain Step#3 in the manual again for me? The top poles of the toggle switch wil be connected to the selector switch ground and the lower poles connected to the central ground nodes, is this correct? Can't remember the wiring anymore, it's been a while. Thanks again. Godspeed.

John Chapman · « **Reply #5 on:** 13 Oct 2004, 10:09 pm »

Hello!

No problem going through it although since it worked beforte I suspect you have it right!

Basically the top lugs connect to the input ground - with just rca connections this can be the ground side of the input selector switch. This is also the same spot the bottom of the primary (the '-' wire on the tx102) will connect.

The middle lugs of the switch connect to the output ground. This can be via the rca connector or by connecting to the central ground lug at the back panel. This lug is also connected to the rca output ground (body of the output connector).

Hope this makes sense!

Thansk!

John