Hum with new RSP-1068

[markmaple]

I just picked up my RSP-1068 on Monday night.
I really like the unit, but I am having a problem.
I was getting a hum in my speakers. After much
investigating, it happens when I have the
multi-channel outputs from the DVD player connected
to the Rotel AND I have a video connection from the
DVD player to the Rotel. If I disconnect all of
the multi-channel outputs or all video connections,
the hum disappears. Any thoughts.

[CWD]

You appear to have the ever popular ground-loop problem. Send me some e-mail and I'll give you some things to try. You may want to search this forum for other posts on the same topic, too.

[markmaple]

I plugged the amp (RMB-1075) and processor (RSP-1068) directly into the wall outlet. The DVD player remained unplugged. I connected the multi-channel outputs and the component video outputs from the DVD player to the processor. The processor is connected to the amp. When I turn power on, I still get the hum. Disconnecting either the multi-channel outputs or the video connections removes the hum. I try different DVD players and different cables. The behavior is consistent.

[hamiltong]

I have the same problem. Ground Loop. Caused by different ground points from my satellite coax feed and my 1068/1095 combo. Essentially the link (problem) is created through the S-Video cable of my SAT receiver to my 1068. Only solution I've found to date is 3->2 Prong cheater plug.. Basically, clipping the ground pin on the 1095 power cord. That being said - I do not recommend this as a permanent solution. -gh

[tombowlus]

Take a piece of wire (I use zip cord style speaker wire, but even very thin wire is fine) and run it from a ground on your preamp (I use one of the screws that runs through the chassis of my RSP-1066) to your amp (ground to chassis) and another wire to your DVD player (ground to chassis), with yet another to your TV (you guessed it - ground to chassis!). This is fairly easy to do, and you can "daisy chain" them. The point is to establish a common ground.

This should eliminate your problem.

Tom.

[Martinf]

I sometimes get a slight hum, but it’s from the TV which is close. When I turn off the TV, I get no hum at all. I had the same hum before I got any Rotel equipment.
So check what other electronic equipment your interconnects are passing close to.

Basically, my interconnects come quite close to the "electron-gun" back end of my TV. However, they are supposed to be electromagnetically shielded. Moreover, when I move these interconnects, the hum either gets louder, or almost disappears (but never completely).

[mule.variant]

I get a hum also, but only in my surrounds and I can't hear it from my seating position. Luckily, I don't reallly need to fix it because of this, but thought I'd chime in anyway since it is there. I may investigate the source at some later date, but it is definately 60 cycle.

[markmaple]

After trying all sorts of combinations tonight, it seems to boil down to I get the hum when I have a video cable and an audio cable connected from the same component. I was always using the multi-channel inputs on the processor. I didn't think until now to try one of the other audio connections. If I only have an audio or video from a component, no hum. I can have an audio from one component and a video from a different component, no hum. I have experience the hum with two different DVD players and my satellite receiver. I guess I need to take the processor in and see what happens at the dealer.

[hamiltong]

markmaple,

With everything plugged in and hum humming away.. Try unplugging just your coax satellite cable (coax plugged into SAT receiver going to dish) and see if that gets rid of your hum. That what I am experiencing with the 1068 - commonly refered to as a 'ground loop' problem. -gh

[markmaple]

I'm getting the hum without the satellite receiver being connected to the processor. The satellite signal was running (via DVI) to the TV and processor was connected (via component) to the TV. No audio was going from the sat receiver to processor.

[hamiltong]

I'd still be interested - did you simply remove the coax cable (SAT feed) from your satellite receiver?

Reason why I ask is that 'ground loop' problems do not only travel audio cables they traverse all electrical cables (video, audio, component video, etc).

I have my SAT receiver svideo wired to my 1068 - this give me a hum. So I moved the svideo cable off my 1068 and directly into my TV - but that also gave me hum.. why..cause I have component video cables on my TV also running to the 1068.

My ground loop chain is a ground differential between my SAT and my RMB1095.

Here's the path: SAT receiver svideo -> TV svideo -> TV component video -> 1068 component video monitor jacks -> 1068 audio outs (LRC&rears) -> RMB 1095 RCA inputs = hum

[MichiganMike]

My dealer received the following reply from Rotel when he inquired about the low level hum produced by my RSP 1068:

It looks like there was a small batch of the RSP 1068s that did exhibit the ground loop as described. The factory has supplied us with a ground modification that will resolve this.

I am hopeful that there will be a fix from Rotel soon for units with the ground loop problem.

[markmaple]

I took my RSP-1068 to the dealer yesterday. We hooked it up to his RMB-1075, a Pioneer Elite DVD player and some B&W speakers. I definitely didn't hear the hum to the extent that I do at home. I do hear the same type of hum if I stick my ear next to the speakers. I think that the speaker's sensitivities might be coming into play. I have high-sensitivity Klipsch speakers. I'm going back next week and taking my 1068, 1075 and one of my speakers with me. They were very helpful. They said that what I'm describing doesn't sound right, but they would like to witness more before sending it back to Rotel. I will mention the Rotel memo when I go back.

[markmaple]

I took my equipment to the dealer today. With my speakers the hum showed up as expected. I also showed them an email exchange that I had with Rotel based on someone else's hum problem. The dealer called Rotel. Rotel said that they had a problem with either a loose or crossed wire creating an unintended loop. They are shipping out a new unit.

[hamiltong]

markmaple,

Hopefully a new RSP1068 will resolve your problem. Keep us posted. -gh

[MichiganMike]

Replacement RSP-1068

My dealer arranged for Rotel to advance ship a replacement for my RSP-1068 due to the hum experienced when video inputs are connected. This allows me to use the current unit until the new one arrives and avoids a long delay waiting for repairs. I am pleased with the customer service.

[markmaple]

I'm getting the same great service from my dealer. They called Rotel today and based on the approval date of the replacement, it might be in tomorrow.

[markmaple]

I picked up my replacement unit tonight. I've basically only gone through the setup so far. The good news is that the hum that I was getting is GONE!

[aud19]

Glad you were able to get one of the corrected, newer units. Happy Listening :T

Jason

[MichiganMike]

Replacement RSP-1068

I also picked up a replacement RSP 1068 and was pleased to discover the hum was eliminated in the new unit.

[chanlon]

I have the exact same issue as this poster from a few years back.

I have a 1068 and 1075 combo that I purchased approx. 2 1/2 years ago that over the past few weeks, produce a humming sound on all channels.
However, once I remove the RCA connections from the 5.1 multi-input (for SACD player), the humming stops on all inputs. I've changed the RCA cables but have had no luck. However, when I connect my CD player to 2 of the multi-channel inputs, its dead quiet. It appears to be a ground loop issue between my Sony 900v DVD/SACD player's analog ouput and the Rotel's 5.1 input.

There is a satallite receiver in my system. However, when I remove the Video and Audio connections from the 1068 and satallite, the hiss remains.
The equipment is plugged into one circuit. I've tried switching outlets for the DVD player, moved around the amp and processor, etc. No luck!

The only fix is to disconnect the SACD/5.1 mult-input from the Rotel 1068. I'm curious to know why this problem has arisen over the past few weeks but was non-existant for years.

Can anybody help? Do you think it could possible be an internal 1068 issue?

Thanks!

[shadow]

Is it hiss or humm since you you use both terms? Hiss has nothing to do with ground issues. Does your DVD player have a three prong power cord? If so, you can use a cheater plug on it and that should cure your humm issue. If not, it is likely an issue with your DVD player, not the 1068 IMO since you have no hum with the analog inputs and your cd player.

[chanlon]

Hi,

Thanks for the reply. Its a hum - sorry should have been consistant.
And, its a 2 prong cord for the Sony DVD player.

Its not a consistant hum. It fades in, fades out, every 2 seconds or so.
It almost sounds like interference. However, the minute I remove the DVD player's analog connection from the Rotel, the stereo is silent again with no him.

[Bluespower]

May want to try a Calrad RF Isolation Transformer (75-504). Costs about $12.

[Alex999]

I posted this before. Good luck.

http://www.audioholics.com/techtips/setup/avhardware/groundloopcableTV.php

[chanlon]

Thanks for the responses. I've tried everything but have had no luck.
I'll bring the DVD player into the dealer tomorrow to see if there is an internal problem causing the hum.

Chris

[eelco74]

Well,

During my holiday I send my RSP-1068 in for repair, because it was humming. It got a replacement digital board, and until now it was hum free.

However in order to see if anything was wrong with my cables, I did not put in the 5.1 cables. This weekend I put them on (all shielded vdHul cables) and there it was, it was humming.

Disconnected the video between the DVD and the RSP, and the hum was gone.
put the video back, diconnected all six 5.1 cables, and the hum was gone again.

It seems exaclty like described above, I cannot have both 5.1 and component video connected.

I received one of the first 1068 models a while ago, and it seems mine is one of them. I send an Email to my dealer, and wait and see what happens. I am pretty pleased that Rotel has a 5 year warrenty.

[chanlon]

This is exactly the same problem I am encountering. I wrote an email to Rotel who suggested trying a RCA isolation transformer. However, I prefer if the unit gets serviced.

Basically, after about a week of trying to locate the problem with the help of my dealer, I isolated the source of the hum as the component and 5.1 analog connection from my DVD/SACD player and the Rotel 1068 processor.
I have attempted to remove the ground loop by trying all of the typical trouble shooting methods. Initially I though my issue was either a complex ground loop or an issue with my DVD/SACD player.
However, I firmly believe that the source of the problem is internal to the Rotel 1068 processor. Once the processor warms up (approx. 1 hour), there is a humming from all of my speakers.

I disconnected all connections from the processor except that of the DVD/SACD player and usual pre-out connections to the Rotel 1075.
When both the component and 5.1 analog connections are made to the multi-in and component video input on the processor, there is a constant hum.
Disconnect either the component OR analog connections, the hum disappears.

In a further attempt to isolate the problem, I connected the DVD player to ANOTHER Rotel processor in the same system. No hum.
I also replaced the DVD/SACD player with a similar player, using the SAME setup, and there IS a hum present. Remove the cables, and the hum disappears again.
(I have tried different cables).

I'm waiting now for a response from my dealer. He is in contact with Rotel.