Hum from both speakers...This is New Please read.

Hi All, I would like to say I am new to channel after a long recovery from mid-fi! I am building a system in my home office. It consists of; Jolida 302crc (new tubes tried ), Jolida glass FX Dac, Jolida jd9, Rotel 2500 turntable..., pioneer elite pd65. Monitor Audio Silver RX2, Epos M Sub.
AQ rocket 88 speaker cable, AQ IC's.

So, the Jolida 302 is new. Since the first setup there has been a hum from both speakers. For the last month, I have been going insane throwing time and money at the problem. I have read, I think, every post on audiogon bout hum and the related links connected to other sites.

So, this AM, I am chasing the problem again, and I noticed that when I disconnect the negative speaker connection on the right speaker it goes away. Dead silent. Plug it back in and It returns. If I do this on the left speaker, it does not go away. Thes are biwired speakers and the hum only goes away on the right speaker, negative, low Freq posts. If I switch speaker sides, hum is still there but removing the right negative does nothing.


Is it the negative speaker post on the amp?
Is it the negative speaker post on the speaker?
Is it the cable?

Could the ground in the amp or the speaker be loose on the right neg. post?

I know this subject has been beaten to death, but I think I am going to need counseling if I don't solve this.

Thanks in advance,

You don't say what type of interconnects you have. I had a problem similar with WBT's, they can be hard to get to affix correctly. That caused and when tightened ended a hum. Hope this helps
Bananas at both ends. Sub bare wire at amp to spades on sub hi pass

Is it the negative speaker post on the amp?
Is it the negative speaker post on the speaker?
Is it the cable?

This should not be too hard to figure out. You have several components that can be the problem. If you isolate each component to verify it is OK, you will narrow things down until you are left with the problem.

Start with the speakers. Switch them from right to left. If the problem doesn't move with them, the speakers are OK.

Now, do the same exact thing with the speaker cables. Again, if the problem stays the same, you have now eliminated both the speaker and speaker cables.

**I just noticed something in your post. You don't say if the problem occurs with just one or both your sources. Unless you say otherwise, I will assume both and that will rule out all source components and cables. ****

Now go to the amp. I know you have tried new tubes. Try this anyway: Turn the amp off and move the tubes from the right channel to the left and from the left to the right---do all of them, not just the power tubes. If the problem follows the tubes, you have the problem.

Unplug your subwoofer and remove the IC. If the noise is still there, I would have to say that there is some type of internal issue in your amp. But first..

Completely disconnect 1 of your sources (TT, phono pre, interconnects and powercords or Transport, Dac, interconnects and power cords). If after completely disconnecting one of your sources the noise is still there, hook it all back up and unhook the other source.

If the noise is still there after checking both sources, my best guess would be something in your amp or your AC. If you can, try the amp in a different location. If the problem follows one of your sources, you should be good enough at this by now to keep going and isolate the problem.

Also, I'm not a repair person of any kind and could have very well overlooked something. Check all the other posts as they may have thought of something I missed.
Blk25, Thanks! I have gone through the above steps and I'm leaning towards the AMP. Nothing else changes the hum. The right negative changes on the speaker are the only way I can make it stop. ( On both speakers ) and switching the speakers lends the same results. So, the question I have now before me is.. Do I open up the AMP and have a look at the wiring (Grounds to the speaker Posts ) or Pack it up and live without an AMP for ~two weeks, I would think. Really a drag. With the new tubes in, it sounds awesome, but I can not live with the hum ( Knowing it is there kills me! )

Thanks for all the help!
When you solve this one let me know. I have an identical problem with one of my amps. And it is the amp! And it has something to do with the amps grounding scheme. This came up a few years ago when I was trying to use it and I researched it. I believe there is a devise which can be inserted between the preamp and amp input/output to remove this hum. I was first alerted to this possibility by an amp designer. I did the research on Google but unfortunately did not keep the references and the specifics nor do I remember them, but it is there. I never pursued this but from what I read it sounded as if it would/could work. I just started using a different amp.

Good luck
Yeah, if you find an answer please post it. I've had the same problem with a Cary
v12r for a couple of months now. Sent it in to Cary for what wound up being a very expensive service (cap upgrade) and they could not duplicate the hum AND it was still there when I got the amp back. Switching to the 4ohm taps helped some. Curious to hear if you can fix yours.
Sometimes it's a ground loop involving the subwoofer. Have you tried unpluging the subwoofer from the wall?? Sometimes the audio isolator works at the rca inputs to the sub if you're running it passively.
Ground "floating" often fixes this sort of thing...I use my REL sub "floated" (it has a switch for this) fine and the whole system is hum free. I also use a PS Audio Humbuster to keep DC crap out of the main amp (currently a Jolida 502P).
That does sound like it could be a ground loop problem, but if so it has something to do with the subwoofer. If you unplug the subwoofer from the wall that should manage the hum.

If not, then my 2nd theory is that there is a wiring bug in the output section of the amplifier.
First off, thanks for all the responses! I tested so many different things yesterday, my head was numb by about 11pm PST. So to know avail, I could not make it go away. Even with cheater plugs on everything and nothing!!!!! Different plugs around the house.... My neighbors house!

So as I sit now, the AMP is now making it's way to the very kind and awesome tech's at Jolida. While it is there having it's hum chased down and killed, I am having the rest of the upgrades done and will be going to KT88 tubes when it gets back.

So for now, I have plugged my 1976 Pioneer SX 850 receiver again and I stand with my mouth agape at how great it really does sound!!!! Clean, smooth, rich, warm and vintage!

I may have to consider keeping it as the preamp and see how that works out.

Thanks again all and I will update when the traveling AMP returns home.

I'm not sure you have tried things in the right sequence.
1. Plug CD player into DAC into pre-amp
2. Plug pre-amp into amp
3. plug amp speaker out to speakers.

Turn everything on. Noise? no. Then plug another component in such until noise comes and you have found the problem. if yes, there is noise from 1-3, then turn everything off and then unplug the DAC from the pre-amp. Turn equipment back on. Noise? no. then it is either the DAC, the CD player or the cables between the DAC and the pre-amp or the cables from the CD to the DAC. turn components off, then unplug each cable one at a time and turn equipment on to see if noise is still there or gone.

The best and easiest way to isolate a bad piece of equipment or a ground loop is to start simple. one source to pre-amp to power amp to speakers and if noise is there, turn off, unplug cd first, then DAC then pre-amp then etc.

once you have found the component, and remember to do this is sequence so that only that component could be the problem, then isolate and repair the component or replace it. lots of times it is a ground loop. I have gotten rid of many ground loops by doing the following. 1). Plug all low level signal electronics (CD, DAC, pre-amp, tuner, TT, etc.) into a power conditioner/source and then plug that into a separate independent outlet. 2) plug the amp into their own separate independent outlets.

I have found that a minimum of three separate outlet runs to the circuit breaker panel is required. All low level electronics plugged into a power conditioner/device, amps plugged into their own separate power outlets.

Thanks for the detailed plan. I like the very structured approach and as soon as the AMP returns, I am going to try your methods.

As far as the outlets, my problem is the distance from the source. Should I purchase long PC's (~12 feet to the next outlets)? What is better, Longer power cords or IC's?

I have some freedom in the room as far as placement and I have been considering a rack on the side wall and running longer speaker cables and/or a mix of components on the front wall. This would be helpful as space is an issue up front.

The System is in my home office. If you look at my system, you can see that everything is sitting on a credenza. I am not happy with this placement.

Some components can go in the cabinet, but I would like to have the Jolida, Pioneer and the VPI Scout (Being delivered Saturday 3/30/12) visible for looks and ease of use. I also have the Jolida Phono Stage, Jolida DAC and a Pioneer Elite CD player. Behind the cabinet are all the cables and a monster HT2500 power center. Any Ideas on optimum placement would be much appreciated.

Thank you for your time already. Any help on the above from you are anyone else that would like to support a newbie, would be great!
Wire World 7M Cable works awesome!
I recently fixed a hum issue that was coming through my speakers. The source believe it or not was my cable box. The way I eliminated it was a little unexpected but was suggested by a very knowledgeable audio friend.

I went outside to the cable box on the side of the house. IT was grounded to the faucet. I removed the ground wire. I then drove a 7 ft copper coated ground stake into the ground and re clamped the cable ground to it. All the hum disappeared at once. Magic.
Ok, I received the Jolida 302CRC back today in the form of a 502CRC (I had it upgraded by Jolida) also, I had all the resistors upgraded. This is now as good as it gets from the factory. I am now using GL Kt88's, Mullard 12AT and NE 12AX input tubes. The Jolida crew was top notch on communication and the work. The sounds is 10X what it was....

No for the HUM, They could not reproduce it. I did not send them my tubes, so they used theirs. The only difference now is the new KT88's and the resistors. I would love to know what it was, but it is very quiet now!!!

Thanks for all the help!
How much did the upgrade set you back? Or are you still covered under warranty? I'm considering sending my 502b for jolida for diagnosis and repair of a transformer hum.
How much did the upgrade set you back? Or are you still covered under warranty? I'm considering sending my 502b for jolida for diagnosis and repair of a transformer hum.
The upgrades to the resistors and the settings for easy bias. Was 70.00 + Shipping. The Upgrade to all the input caps was 100.00. Mine was very new so all the Hex stuff and other upgrades came from the factory.

I will tell you this. It is a brand new AMP... The KT88's and the resistors put it in a new world.

It feels faster and has much better mid-range. The high end is more refined and bass response is tighter.
Buy a PS Audio power cord. I bought the least expensive one. Unscrew the ground pin on the male side (PS is the only cord I know of that you can do this with) I had the same problem, this took care of it. You can get a three to two adaptor from your local hardware store that will acccomplish the same thing. I already had the PS so no real expense.
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I haven't read all replies, but I have been chasing a hum issue and just resolved it this morning so this might help.

In my case I isolated the problem to the preamp and it was causing the issue (ground loop,) I put a 3 to 2 prone adapter in the power cord and it's dead quiet now.

Wire connectors are what I suspect first, ones that just aren't isolated well enough allowing them to pick up interference, or they were damaged. In one case I got some that were bad from the get go after un-packaging them. Some amplified sources are more susceptible one set of connections might work perfectly well on one source and may not on another. Also take care while removing them in confined spaces they can be easily damaged. A dap of dielectric grease can save a lot of headaches. 
I had a hum I chased for months . Finally noticed a flicker in the house lights and called DTE to come out to check my service line , the neutral leg had corroded and caused the problem . They replaced the connectors on the house and transformer and all has been good .
That's great to hear they took care of you.  While this thread is fresh I wanted to share a weird experience I had recently.  I was listening one night and every 20 seconds I heard a noise, not quite a hum and not quite a buzz.  It was strange, it lasted just a second or two and came back every 20 or 30 seconds.  I had just re-tubed my amps, Quicksilver Mid Monos so I suspected my preamp , a c-j Classic 2SE which is tough on tubes.  I replaced the 6922 with an EH and also a NOS Philips 6dj8 and the problem was still there.   I had also recently changed all the light bulbs in my house to LED so turned them all off and it was still there. .....frustrated , I began unplugging every  thing in the house one by one......It turned out to be my son's Ethernet on Ac adapter which uses the house's wiring to transmit data.  He needed it for his PS4 because Wi-Fi just wasn't fast enough.  I pulled an Ether net cable through the floor, problem solved.  Just goes to show sometimes it's the component but sometimes it's the environment it's in