I have a problem encountered over the connection between my integrated and av amp.
I am using an integrated, Dussun V6i, which comes with a U bridge at the back for the connection of pre-out and main-in, making it either serving as an integrated amp when the U bridge is inserted in place, or a pre-amp or power amp only when the U bridge is taken off. It's a very silent integrated. I even cannot hear any buzz or hum when I get my ear closed to the HF speaker driver.
I am also having a Marantz AV Receiver, SR5400. When I connected its front pre-out to the main-in of my integrated, Dussun V6i, I heard noise from the HF speaker driver when my ear was 10"-12" away. Again, if I use the SR5400 alone, it is silent and I cannot hear any noise even my ear get closed to the HF speaker driver.
Why both amp's are silent when used alone, but noise is generated when connected together? How can I, if possible at all, get rid of such annoying noise?
Thank you in advance for all the solutions suggested from you folks all.
It's unlikely you can get rid of the noise. The two units are not all that compatable. The incompatability is most likely due to the input sensitivity of the integrated amplifier and its front circuit gain. Possibly some minimal filtering of the inputs on the integrated is also letting more nosie through. If the integrated boasts low or no negative feedback, this would be my first suspicion. You can't change the circuitry so, you'll have to decide how you want to use the two pieces. Make certain both components are plugged into an AC circuit with the same ground plane for all outlets. If you use a surge suppressor or line conditioner, this might not be the case for all outlets.
Thanks Jan once again for your comment and reply to my question. However, I connected the front pre-out of my AV amp to the main-in of integrated, did the input sensitivity of integrated matter?
It matters big-time Eddie. If your in/out sensitivities do not match, you could run into over driving the amp, or overpowering the input(most of which are limited to overinput), but inducing the worst part of the amp.
If the input sensitivity/gain are giving substantial boost to the incomming signal levels, then you could be amplifying all the residual noise from the input component. Quite honestly, it's all but impossible to do anything but guess at the problem over a forum. Is it possible the integrated is reacting to transformer noise from the receiver? Possibly moving the components away from each other would help.
You might also check for AC polarity. It's possible one of the outlets is wired backwards or one of the amplifiers is wired to invert phase. You can check for AC polarity with a cheap line checker from Home Depot or, if one unit doesn't have a polarized AC plug, just reverse the direction of the plug at the wall outlet. You can check for phase within the electronics by wiring up some cheap solderless RCA's from Radio shack and reversing the conductors from a normal connection, hot to ground and ground to hot.
Not that I wish to disagree with the likes of Jan and Nuck, but I have seen this kind of thing happen when some kind of loop is created between the two amplifiers thanks to a lack of earthing between them. Try plugging them both into a multiway block off the same socket and see if the noise goes away or diminishes. If it does then the loop is being caused by the electrical earth levels in the amps. Sometimes this is very hard to get rid of completely. It depends on the earthing arrangements in the various components and the loop can even be caused by a source component (e.g. DVD player). This is one reason I tend to advocate plugging in the whole system to one multiway block since that often gets around earthing issues like this.