New set-up

dex67 · « **on:** 16 Sep 2014, 01:45 pm »

Well, I finally found a long pair of interconnects (8m Dana Cable Diamond interconnects to match all the other Diamond series cables in my system) and I decided to change things a little. having a new Pagode rack on loan made things even easier. I unhooked everything, and I placed the new rack close to the left wall leaving only the monoblocks and a thick rug between the Nimbus. Here are some pics...

I also removed the round coffee table...this last picture was from the sitting position on the floor in front of the couch...

And what do you know? The bass got tighter!!!! Now it is almost to my liking...The problem is that I need a long pair of interconnects for this set-up. About 5m, and those cables are not cheap...I'll have to figure something out.

But here is the bummer...as soon as I turned everything back on, I had this loud hum in the speakers. I unplugged and plugged everything back on. I haven't changed power cords, or power conditioner, nothing, but the position of the equipment. See that lamp on the top shelf? I had it before and it is there just so I can see the small dust particles on the LP to clean it before playing. I unplugged that lamp and the hum dropped significantly, but it is still there...loud enough to hear from the listening position. hard to tell when the music is playing unless there is a very quiet passage. Ah, the hum increases with the volume...I can hear it from the tweeter, and I can feel a very low vibration in the woofer... I unplugged the CD player, the phono stage, no change.

Why do I have this hum? Don't tell me that the new rack is the problem...Any ideas? I tried to run a ground wire from the preamp to the power conditioner...nothing...then ground wire from the preamp to one of those big metal poles that support the ceiling...nothing...

Grrr! Now that I almost fixed the flabby bass, I've got this low level hum to deal with...

Adrian

jparkhur · « **Reply #1 on:** 16 Sep 2014, 01:57 pm »

Are you plugged in to wall at a different spot?

Try different plugs on conditioner ?

dex67 · « **Reply #2 on:** 16 Sep 2014, 02:00 pm »

same wall socket (designated 20Amp line)...tried all different plugs in the power conditioner...no change...

tvyankee · « **Reply #3 on:** 16 Sep 2014, 02:04 pm »

My guess is that you are now on different phase of power between the power outlets from before. As a test I would run a extension cord and power strip as a test and power the mono blocks from the same power source as the equipment and see what you get.

Let us know.

jparkhur · « **Reply #4 on:** 16 Sep 2014, 02:06 pm »

Cords crossing? RCA or power?
Move pre to different level, take off shelf to test

Move amps? Are amps in same socket too?

I hate ground issues.

RCA plug not fully in or untwisted at connector?

mr_bill · « **Reply #5 on:** 16 Sep 2014, 02:23 pm »

Adrian,
What mono amps are those in the pic?

jtwrace · « **Reply #6 on:** 16 Sep 2014, 03:18 pm »

...and if you take what you have now that you think sounds good and add some room treatments your jaw will be on the ground.

dex67 · « **Reply #7 on:** 16 Sep 2014, 03:45 pm »

the monoblocks are the Emerald Physics 100.2...probably the best deal in audio for the money!!! I've had plenty of amps in my system (Sanders, KR monoblocks, ML, Wells, Red Dragon monoblocks, etc) and these are by far the best sounding!

as for the other suggestions...yes, the amps are running of the same power source as the other components...one thing that I realize that is different...the interconnects are all now touching the left wall...because the rack is so close to it...should I move the rack a little bit more forward to have the cables all hang in there loose? can this be the reason of the annoying hum?

rollo · « **Reply #8 on:** 16 Sep 2014, 03:58 pm »

Double check the RCA connections to make sure they are IN all the way. There shold be no reason for the change. The new ICs may be it as well. Any special grounding scheme for the new cables ? My guess it is an IC not plugged in all the way. Good luck.

charles

JLM · « **Reply #9 on:** 16 Sep 2014, 04:11 pm »

Change only one thing at a time so you know what works/doesn't work.

Big Red Machine · « **Reply #10 on:** 16 Sep 2014, 04:15 pm »

Could the longer cables be picking up noise?

DaveC113 · « **Reply #11 on:** 16 Sep 2014, 05:53 pm »

Quote from: Big Red Machine on 16 Sep 2014, 04:15 pm

Could the longer cables be picking up noise?

I was going to say... very long ICs, if they are not balanced/shielded, could be an issue...

To offer more we need to know if everything is running on the same power conditioner/distribution box? If not, try that.

DaveC113 · « **Reply #12 on:** 16 Sep 2014, 05:56 pm »

Quote from: tvyankee on 16 Sep 2014, 02:04 pm

My guess is that you are now on different phase of power between the power outlets from before. As a test I would run a extension cord and power strip as a test and power the mono blocks from the same power source as the equipment and see what you get.

Let us know.

Beat me to it!

dex67 · « **Reply #13 on:** 16 Sep 2014, 08:14 pm »

as jparkhur suggested, i tried and i pushed all the interconnects back in and i jiggled them a little…that almost did it!!!! right now there is a little hum in the speakers, but at a lower level. it might be that i have to live with this hum since i'm using long interconnects and this is a tube preamp…

and yes, i have all the equipment plugged in one power conditioner….

adrian

jparkhur · « **Reply #14 on:** 16 Sep 2014, 08:25 pm »

Not sure if u can but if you exchange or switch ic with different comps you get a more less hum.

persisting1 · « **Reply #15 on:** 16 Sep 2014, 08:42 pm »

A slight hum can ruin a perfect day. I know your pain

tvyankee · « **Reply #16 on:** 16 Sep 2014, 09:27 pm »

You don't have to live with it and you shouldnt. If you have a digital volt meter you should buzz out your cables to make sure they are good beyond any doubt. I am sure they are good cables but I have had 100 thousand dollar machines out of the box not turn on . Bad power supply. My point is anything is possible. If you have and old extension cord make it into a speaker cables move the amp closer to the preamp and use a short Ic. Then see what you get. The last thing or first thing is disconnect Ic from amps and see if there is any hum without the Ic connected to the amps then put one back at a time. Make sure nothing is connected to pre amp . If there is no hum then start to connect one cable at a time and listen for hum. Just make sure u do one at a time.

You will find it don't quit.

paul79 · « **Reply #17 on:** 16 Sep 2014, 10:44 pm »

The long interconnects is likely causing the issue. Depending on the tube preamp, it may not have sufficient drive to run the longer cables, making them act as an antenna of sorts.

I'd try some more careful routing of the interconnects, keeping them away from power cables and maybe getting them up off the floor a tad and see what happens.

DaveC113 · « **Reply #18 on:** 16 Sep 2014, 11:01 pm »

Good point on the preamp, do you know the output impedance or what circuits it's using? For this setup it would be best to run balanced cables driven by a low output impedance preamp. I agree with tvyankee's advice for finding it, once you do that let us know what's causing it. Good luck!

tvyankee · « **Reply #19 on:** 16 Sep 2014, 11:13 pm »

Hey. Forgot about the tube pre thing. Might want to check with manufacturer. Sometimes not a lot but sometimes on the output they are out of phase. Sounds crazy but I believe that happens once in a while.

This may or may not have anything to do what we are talking about but I just popped into my head when i read tube pre.

So many things to think about.

Audio is fun isn't it?