Humming sound?

chgolatin2 · « **on:** 14 May 2007, 12:48 pm »

I am no expert in tubes but I do love their sound but whenever I turn on my Jolida 1000RC I hear a humming sound coming from it. Do most big powered tube amp produce a humming sound noise? Is this normal, can it be eliminated, controled etc?

1000a · « **Reply #1 on:** 14 May 2007, 03:11 pm »

I get no humming sound ever from my 1000a had it since 2002, bought used.

So something is up, what it is I am probly not the guy with the answers, my take is a ground loop in the system, check your cables make sure they are not all bundled neatly-bad idea.

if they cross each other should be at 90 degrees looking down looks like this +

could also be a tube issue not seated right, bais could be off.

wait for the experts to chime in.

arthurs · « **Reply #2 on:** 14 May 2007, 04:05 pm »

Humming from the amp itself or through the speakers?

From the amp itself, 1000a had some of the first things to check. Also, you could have some DC on your lines which can saturate your transformer and make it hum, not all that unusual...

nodiak · « **Reply #3 on:** 14 May 2007, 04:12 pm »

I've had to work on this too. What I learned is to isolate the amp from the sources by unplugging all sources from the amp and wall outlets. Eliminates sources and their cabling. Run only the amp with speakers hooked up. Also no other lights/appliances/etc. plugged into same wall outlet, or if possible same house circuit. Still hum? Then either amp or house circuitry.
Here's some info on this and chasing down possible house wiring problems.

http://www.angelfire.com/biz/bizzyb/hum.html

Anybody please correct any of this.
Don

avahifi · « **Reply #4 on:** 14 May 2007, 09:15 pm »

That was a fine and thorough article of chasing down hum, and very accurate.

However, they missed one cause.

The unit does not know the words.

Regards,

Frank Van Alstine

gooberdude · « **Reply #5 on:** 14 May 2007, 09:29 pm »

Hey Robert,

Does the hum change at all when you plug that QuietLines filter in???

Also, did you notice the hum before...i don't recall hearing a hummmm when i was at your place a few weeks ago.

If its a new hum, it can probably be corrected easily - you need to hunt down the source though.

chgolatin2 · « **Reply #6 on:** 14 May 2007, 11:25 pm »

Hey Matt, yeah I know I have to find the source and correct the issue asap. My rack come in aa going to purchase some sand from home depot to fill the legs up and set all of my audio gear on it and the tt. I cant wait to hear my sounds again, hmmm, such an addiction...

arthurs · « **Reply #7 on:** 15 May 2007, 12:02 am »

Is the hum present every single time you power up, or is it intermittent?

chgolatin2 · « **Reply #8 on:** 15 May 2007, 05:29 am »

The hum is audible when I turn on the amp, however, i cant hear it meanwhile I am playing some tunes but thats to be expected.

gooberdude · « **Reply #9 on:** 15 May 2007, 02:22 pm »

Robert,

be sure to get Kiln Dried sand...not the normal playground stuff. it has water in it & might cause the legs to rust.

I keep hearing that kitty litter might be best.

arthurs · « **Reply #10 on:** 15 May 2007, 02:25 pm »

Quote from: chgolatin2 on 15 May 2007, 05:29 am

The hum is audible when I turn on the amp, however, i cant hear it meanwhile I am playing some tunes but thats to be expected.

But is it there every single time you power up the amp? I'm asking because if it is DC on your lines, it might be there sometimes and not others, or louder sometimes and softer others...

avahifi · « **Reply #11 on:** 17 May 2007, 12:10 pm »

Is the hum there if you disconnect the input leads to the amplifier, leaving just the amp connected to the speakers?

If so it is an amplifier issue.

Frank Van Alstine

chgolatin2 · « **Reply #12 on:** 17 May 2007, 04:34 pm »

the humming sound is unique especially whenever I turn on the integrated amp. Due the music I will not hear the humming sound however I dont think that is a normal thing. I was told by Jolida that due the integrated tube amp having so much power that it may produce a slight noise (humming) and thats perfectly normal and that it shouldnt affect the music.

So thats my lil small issue...

1000a · « **Reply #13 on:** 17 May 2007, 04:50 pm »

my 1000a I bought used in 2002 has no hum, no noise what so ever.

"Is the hum there if you disconnect the input leads to the amplifier, leaving just the amp connected to the speakers? If so it is an amplifier issue.
Frank Van Alstine"

yep definitly do that! I can't imagine Jolida saying its normal, unless this hum is far lower-quieter than your post has me or others believing.

gooberdude · « **Reply #14 on:** 17 May 2007, 04:57 pm »

Robert, disconnect the interconnects from your cd player so that the ONLY cabling plugged into the amp is your power cord and the speaker cables...then turn the amp on.

If there's an audible buzz then you might have an amp issue. OR, it might just be a bad tube. anyone??

Since you've been having odd tube problems also, the tubes might be the source - not the amp.

Guys....his new bad-ass amp turns itself off after 1 hour of play....does this seem normal? i think Robert has contacted Joilda about it, and had his tubes tested by a local shop but still the problem persists. It doesn't sound like the dealer he bought it from is willing to assist either.

is this correct Robert? you have hum now & prior to the hum an issue with the amp shutting down???
please remember your Shanling Gear....ling-a-linga-linga-linga-ling-ling-ling.

1000a · « **Reply #15 on:** 17 May 2007, 05:08 pm »

robert

first do the test w nothing but the speakers and let us know.

if its still noisy.

did you replace all the tubes recently as you said?
if 1 tube went recently there may be another ready to go- acting funny.

did you bias the tubes or did someone anyone bias them?

chgolatin2 · « **Reply #16 on:** 18 May 2007, 04:54 am »

I did the auto bias option

was considering purchase a multimeter and doing it the old fashion way to see, i will keep you guys posted! It seems to me that Jolida is giving me some slack and not asking for me to return the unit to them after i called them a few times about the amp shutting down, they stated to check the tubes blah blah blah, test the tubes which i did and all the tubes tested good except a pre amp tube that was testing below the standards. They also said that i could return the unit and that is the unit did not have anything wrong that I will have to pay for the shipping and some other crap but I cant remember verbatim.

Matt, lol Shanlin

1000a · « **Reply #17 on:** 18 May 2007, 05:37 am »

matt

if you want to fix the problem, you must do exactly these things:

1-Replace that pre amp tube, NOW.

if that does not fix it.

2-do the test w nothing but the speakers?

then get back to us.

1000a · « **Reply #18 on:** 20 May 2007, 04:42 pm »

OK, I am all confused, you are Robert not Matt.

Sorry I have no right to tell you what to do

, I apologize. It was wrong.

I would like to see you get rid of the hum, I think because you have a pre tube that is off, it could easily be the problem, there is no way to adjust the pre tubes. Anytime a tube is out of spec in anyway, problems will arise in a tube amp.

"test the tubes which i did and all the tubes tested good except a pre amp tube that was testing below the standards."

In addition the auto bias on your amp is for a average family, not an audio guy, its not accurate. Biasing the tubes with a volt meter is necessary to keep it up to standards audio guys except from their gear. Tubes way off in their bias can cause problems also.

Please be aware if you bias the tubes yourself, a tube amp contains lethal Voltages and can kill. If you chose to do so do your homework first.

Hopefully this helps, biasing tubes is not hard but one must be carefull! I have done mine numerous times but you would still be wize to check with guys more experienced than I or pay someone to do it with a volt meter, forget the auto bias, it does not cut it.

Bill Baker · « **Reply #19 on:** 20 May 2007, 04:49 pm »

Hello robert,
we do not know exactly what your systems contains but I would recommend taking a look at another thread here at AC. All the information would also apply to your situation as well.
The Jolida tubes can be dead quiet and any noises are usually cause not by the amp rather by either tubes or something else in the system.

Here is the link to the other thread.

http://www.audiocircle.com/index.php?topic=41113.msg367240;topicseen#new