2. amps-preamps
  3. 1332600947

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.

So,

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,

Troy
plosive

Showing 1 response by minorl

minorl
1,014 posts
 
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.
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