Huummmm

[Chazzy]

I finally have my system hooked up for the first time and I'm getting hum through my speakers.

This is a deducted listening room with no tv or cable.

My Cary Slp98p pre amp has a ground lug and the manual simply says " for connecting to turntable "

do I need to connect a ground wire from the Pre amp to the turntable?

The hum changes in relation to volume and L and R input level.

 

[ImcLoud]

TT should be grounded to amp or receiver, and make sure your RCA cables have a good connections...

 

[Chazzy]

Ok. Thank you.

 

[Actran]

Here is a must read for you - great article with some very practical solutions. I had the same issue with my setup. Stepping through this guide helped me isolate the problem. Mine actually ended up being related to a cable I used to hook my subwoofer up with. An order from monoprice and $10 later I was all set.

Ground Loops - Eliminating System Hum and Buzz | Audioholics

 

[Chazzy]

Thanks ACTRAN....looks like a great article!

 

[buster777]

Hi All,

I'm new to the forum. I have a Proceed 5 channel amp and matching sound processor. When I purchased it over 12 years ago it was incredible....I used this system to drive the following: 2 B & W front, 2 B &W rear, 1 B & W center and a Rell sub. System was great for about 5 years. Then it developed a hum and the amp was sent back to the factory and an came back with a hum.



The home theater outfit that sold me the amp (now out of business) tested the amp and pre amp in my presence and it was clear the hum came from the amp. They sent amp back to the factory and the problem persisted.

I have tried the following sound conditioner and they didn't work. I have also spent a few bucks on high end cabled....didn't work.

End result is that I still have the pre amp and amp on a shelf and I'm driving these nice speakers with an inferior integrated amp.
So, I have the following questions:

Is there something I've overlooked or is there new technology that could properly diagnosis and correct the problem?

Is there a new modestly priced and lightweight 5 or more channel power amp that would complement my Proceed Sound processor?

Is there a home theater company in PHX or Scottsdale that could consult at a reasonable price.



Thanks!

 

[TLS Guy]

Hi All,

I'm new to the forum. I have a Proceed 5 channel amp and matching sound processor. When I purchased it over 12 years ago it was incredible....I used this system to drive the following: 2 B & W front, 2 B &W rear, 1 B & W center and a Rell sub. System was great for about 5 years. Then it developed a hum and the amp was sent back to the factory and an came back with a hum.
I have the following:

The home theater outfit that sold me the amp (now out of business) tested the amp and pre amp in my presence and it was clear the hum came from the amp. They sent amp back to the factory and the problem persisted.

I have tried the following sound conditioner and they didn't work. I have also spent a few bucks on high end cabled....didn't work.

End result is that I still have the pre amp and amp on a shelf and I'm driving these nice speakers with an inferior integrated amp.
So, I have the following questions:

Is there something I've overlooked or is there new technology that could properly diagnosis and correct the problem?

Is there a new modestly priced and lightweight 5 or more channel power amp that would complement my Proceed Sound processor?

Is there a home theater company in PHX or Scottsdale that could consult at a reasonable price.



Thanks!

Not enough information.

Does the power amp hum if only connected to the speakers and wall outlet, and not connected to the preamp. Does the hum appear when you connect the preamp, without the preamp having any inputs connected.

If so, what are the AC plugs on your preamp and amp?

These issues are generally ground loops and you likely have one.

If the power amp powered on hums just connected to the speakers, it is faulty and needs service by someone competent.

My hunch is that your equipment is fine, and your problem is a ground loop, but that is easy to determine, if you post all connections in great detail.

 

[buster777]

Tried ground loops at home and on the shop bench from the company/store that sold it to me... still the buzz...but I will try powered power amp to speakers...thanks! I'll post the results

 

[TLS Guy]

Tried ground loops at home and on the shop bench from the company/store that sold it to me... still the buzz...but I will try powered power amp to speakers...thanks! I'll post the results

You can't buy a ground loop!

Ground lops are differences in potential between multiple grounds. They are caused by inadvertent set up issues related to grounding and are common.

When we get posts like yours, which are frequent, 99% of the time the issue is a ground loop due to the owner not understanding the problems of multiple grounds and proper system layout and interconnection.

 

[slipperybidness]

You can't buy a ground loop!

Ground lops are differences in potential between multiple grounds. They are caused by inadvertent set up issues related to grounding and are common.

When we get posts like yours, which are frequent, 99% of the time the issue is a ground loop due to the owner not understanding the problems of multiple grounds and proper system layout and interconnection.

Even when you do understand ground loops, it can be a pesky little problem to find and solve. I suspect most of us have pulled our hair out on these a few times.

 

[buster777]

I meant to say ground plugs (I know...very bad and novice like on my part)! I isolated all the connections and the hum continues to come from the right rear channel...same hum with different high end connectors and speaker cables in different rooms. I did not use the cable system so I don't think it's a cable isolation issue. It's likely I still could have missed something?? If not, my difficulty is finding an av company in the PHX metro area that can correct this.


Thanks for your patience and feedback!

 

[TLS Guy]

I meant to say ground plugs and I isolated all the connections and the hum continues to come from the right rear channel...same hum with different high end connectors and cables in different rooms. It's likely I still could have missed something. My difficulty is finding an av company in the PHX metro area that can correct this. Thanks for your feedback!

If you will just cooperate a little we can help you isolate the problem and correct it.

All that is requited is for you to follow our instructions.

Please answer the first step. Just have your power amp, powered up and ONLY connected to your speakers. Nothing connected to any inputs. In that situation is there hum or not, and if there is, is it any less?

We need to know that first.

 

[Grador]

If you will just cooperate a little we can help you isolate the problem and correct it.

All that is requited is for you to follow our instructions.

Please answer the first step. Just have your power amp, powered up and ONLY connected to your speakers. Nothing connected to any inputs. In that situation is there hum or not, and if there is, is it any less?

We need to know that first.

I'm virtually positive by "isolated all the connections" he means he did exactly what you asked.

 

[buster777]

This was one of the 1st things I did and they also did this at that shop where it was purchased....and it was sent back to the factory and returned with the same problem...like I said the shop is no longer in bizz

 

[TLS Guy]

This was one of the 1st things I did and they also did this at that shop where it was purchased....and it was sent back to the factory and returned with the same problem...like I said the shop is no longer in bizz

In that case there is a problem in the rear right channel amp board.

Proceed was made by Madrigal Audio Labs, although a Harmon company they have long since closed their doors.

If you want the amp fixed, then you need to find a tech with at least a circuit and preferably a service manual.

The procedure is to disconnect the -ve feedback on that channel and the use a scope to find where in the board the hum is being generated.

It is hard to find good experienced techs these days. Practically no one is going into the field and many have left.

The pickings are slim in your area. But you do have some places to try.

Obviously the tech at Mondial was sloppy. He probably just checked a channel or two, unless you specified the exact problem with a covering letter, and found no hum on the channels he tested and assumed you had a ground loop.

If you don't want the hassle of repair, look at the Outlaw multichannel amp.

That is probably your best bet, a cursory review on the Net, indicates that Proceed amp is a problem child.

 

[Chazzy]

After connecting my ground from turntable to pre amp a lot of it went away put there is still a little but I will continue to read up and get edgumacated..

 

[TLS Guy]

After connecting my ground from turntable to pre amp a lot of it went away put there is still a little but I will continue to read up and get edgumacated..

Just use a grounded mains plug on the preamp. If the power amp has an earthing pin, then lift it with a ground break. Most preamp/amp situations do not like both units grounded. It is best practice to just ground the preamp.

 

[buster777]

Thanks for the advice and the link. I was thinking about trying out a two channel amp to drive the two rear channels and continue to use the Proceed to drive the remaining channels. If this is a viable solution could you recommend a reasonably priced two channel amp....just looking for 100 per channel. I'm really looking to salvage as much of this amp as possible since it's difficult to find a repair shop and it's heavy and I'm and old dude with a bad back.

 

[TLS Guy]

Thanks for the advice and the link. I was thinking about trying out a two channel amp to drive the two rear channels and continue to use the Proceed to drive the remaining channels. If this is a viable solution could you recommend a reasonably priced two channel amp....just looking for 100 per channel. I'm really looking to salvage as much of this amp as possible since it's difficult to find a repair shop and it's heavy and I'm and old dude with a bad back.

This is more powerful than you need, but is probably the best value for your money.