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
blueskiespbd's avatar
blueskiespbd
161 posts
 
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.
plosive OP
16 posts
 
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!
texlle
3 posts
 
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.
texlle
3 posts
 
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.
plosive OP
16 posts
 
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.
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