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View Full Version : Marantz 2215B Phono Problem mnrider 10-30-2007, 05:31 PM I am getting a loud humming sound when i switch to the phono imput. I am using a Pro-Ject Debut III. I also have a speed box and a phono box hooked up to it. I am starting to think that this receiver needs to be restored. any suggestions? Thanks marantzfan 10-30-2007, 05:33 PM I am getting a loud humming sound when i switch to the phono imput. I am using a Pro-Ject Debut III. I also have a speed box and a phono box hooked up to it. I am starting to think that this receiver needs to be restored. any suggestions? Thanks Hmm...Is it just the phono, or does the tuner and other inputs do the the same thing? mnrider 10-30-2007, 05:36 PM just the phono marantzfan 10-30-2007, 05:38 PM Okay, very stupid question...Are you sure the ground is connected on the back of the receiver? mnrider 10-30-2007, 05:41 PM the ground is connected to the phono box. the interconnecting cables that go back to the receiver do not have a ground for the chassis on the receiver. marantzfan 10-30-2007, 06:05 PM the ground is connected to the phono box. the interconnecting cables that go back to the receiver do not have a ground for the chassis on the receiver. Hmm..Never seen that before..But I know that the one time I forgot to connect the ground to my amp..HUMMMMM Are you sure that your not supposed to connect a bare wire from the "ground" on your table to a ground on the amp/receiver? Thats my guess thus far.. mnrider 10-30-2007, 06:18 PM i used to have the turntable connected directly to the receiver, and there was no hum. But than i decided to use the phono box to try and get a better sound. that is when the hum started. mnrider 10-30-2007, 06:28 PM how can i use the phono box without getting any hum? Fred Longworth 10-31-2007, 02:27 AM Many phono preamps are improperly grounded. I will not name any names, but in one instance I actually spoke with the manufacturer and based on my advice they altered the grounding of the preamp so that it was both more durable and more electronically correct. In any case, first try hooking the ground wire to the metal chassis of the receiver instead of to the preamp chassis. This is likely to reduce the hum significantly, but not entirely. Step two is to hook the chassis of the preamp to the chassis of the receiver. Yes, you're using TWO separate ground wires. Why? Because the chassis of the preamp is floating!!! Best, Fred luvvinvinyl 10-31-2007, 07:06 AM Did I read correctly that you are using a phono box into a phono input? The phono input has a phono stage, so either use the phono input, OR use the phono box into an AUX/Tape In input. Try that, and see if the hum persists. If it does, then follow Fred's advice. |