Hello everyone. I have a situation which I hope that you might be able to shed some light on. I have recently purchased a NAD S250 amp and was hoping to connect it to my Denon AVR 785. When I used the pre out on the Denon to connect there is a strong hum coming from the speakers. If I disconnect the RCAs it stops. There is a signal coming through the amp but the hum is loud (worse as i turn up the gains on the amp). Can't figure out where I have gone wrong.
I read another post about grounding but I just find it hard to imagine this much noise could be be as a result of that type of situation. Usually pretty handy with electronic equipment but this has me confounded!!
I am looking forward to cranking this thing up so any tips or suggestions to point me in the right direction would be greatly appreciated!
Welcome PU. You will have to sort out the incoming power and grounds first. Are the 2 units sharing a common recepticle/circuit? Are both units equipped with grounded plugs? You can try a ground lift adapter on one or both of the units. You can temporarily ground the units to each other with a wire. Are your outlets new/grounded/tightly connected? Start with the basics.
Are the 2 units sharing a common recepticle/circuit?
Yes. Both are plugged into a monster surge protector. Is this good or bad?
Are both units equipped with grounded plugs?
The NAD amp has a ground plug the Denon receiver does not.
You can try a ground lift adapter on one or both of the units.
Is this one of the 3 to 2 prong adapters? If so, are they legal to purchase in Canada?
You can temporarily ground the units to each other with a wire.
How would i do this? What points should I make the ground?
Are your outlets new/grounded/tightly connected?
This could be the nightmare. I rent in a building that is likely 150 years old and the landlord is the Mr Roper of handymen. I have no way of knowing what is done right in this place. Can I check this with a simple electronic tool?
Thanks for the assistance. I will work on locating a ground lift adapter and try that.
Just another thought. I use a cable booster pre TV. Suppose I should knock this offline too eh?
I did what you said in regards to a ground lift adapter (actually had to make a cheater ext. cord with the ground broken off) and it worked. Crazy!
I don't really need to know how this works (I'm sure it is rather complicated) however I would like to know if this is safe to run the amp like this long term. Is it or is there a long term fix (besides redoing all the electrical in my place)?