Welcome, Guest. Please Login or Register
Decware Audio Forums
11/26/14 at 01:37:58


Pages: 1 2 3 4
Send Topic Print
SE84C-EX Hum (Read 12270 times)
144cubits
Ex Member



SE84C-EX Hum
01/14/05 at 16:55:38
 
My EX was finally hooked up yesterday after a series of mishaps for which Steve Deckert was most accomodating. As I excitedly popped in the rectifier tube and flipped the switch. My excitement turned to dismay as a very audible hum was heard both from the speakers ( at a distance of 7 feet) and the amp itself?!  :'(

Now I am not technical whatsoever so I do need some very rudimentary (talk to me like I'm a 10 year old) instructions to try to eliminate this very distracting buzz.

I've left a message for Steve but was hoping you guys could help a new member of the family out!

I covet your suggestions.

Fred
Back to top
 
 
  IP Logged
nodiak
Ex Member



Re: SE84C-EX Hum
Reply #1 - 01/14/05 at 17:24:06
 
oh man, say it isn't so! This problem seems to be hit and miss from those that have the ex mod. I'm expecting my C back from decware soon, after having the ex mod. A loud hum would be very disappointing. I know zip about this but there has to be a solution...right? Don
Back to top
 
 
  IP Logged
Gary_H.
Ex Member



Re: SE84C-EX Hum
Reply #2 - 01/14/05 at 18:33:48
 
Try the link below of Stev's paper on hum problems.

http://www.decware.com/newsite/mainmenu.htm

If the link dosn't work go to the Articles section of the main menu and see the Hum Problems article.

I hope you find an answer there.

Gary
Back to top
 
 
  IP Logged
selmerdave
Ex Member



Re: SE84C-EX Hum
Reply #3 - 01/14/05 at 18:34:32
 
What do you mean by mishaps?  Obviously something is wrong.

Dave
Back to top
 
 
  IP Logged
dc007
Ex Member



Re: SE84C-EX Hum
Reply #4 - 01/14/05 at 19:01:49
 
welcome Fred...
I too have noticed a more noticeable hum from my EX C, however it is not distracting and does not interfere with the music at all but still in a dead quiet room you do notice it at about 2 feet.
Are you sure your interconnects are good? Unplug all but the speaker cables and see what gives. Do not power the amp up with no speakers hooked up. Also do you have a new set of tubes....possibly a bad tube and lastly is the power source a reliable one?

Good luck
Mike
Back to top
 
 
  IP Logged
144cubits
Ex Member



Re: SE84C-EX Hum
Reply #5 - 01/14/05 at 19:16:18
 

[quote author=selmerdave  link=1105725338&amp/0#3 date=1105727672]
What do you mean by mishaps?  Obviously something is wrong.

Dave
[/quote]

Well I'm going to try to make a very long story short.

When I called Steve to determine delivery time he informed me that the unit was delayed due to a small blem on the case. He gave me 2 options I elected the second.

Upon delivery the unit wouldn't power up, after trying everything I called Steve. He thought it was a bad rectifier that had blown the fuse. He told me to remove the bad fuse and replace it. I got home promptly popped out the IEC and voila! No Fuses.  

Called Steve again explained the unit was shipped without fuses, he apologized and told me the type and amperage so  I promptly picked them up at RS and gleefully popped one in.
Voila! All tubes glowing except the rectifier. Upon closer examination I noticed bits of metal sloshing around inside.

Back to Steve, he overnighted a rectifier (UPS delivered 2 days later, but that's another story) It arrived yesterday and ...well you're up to date.

Couple of points I'd like to make:
1) I bought a SE84C with the EX mod I was not a previous owner.
2) Steve was very accomodating and I sensed he felt badly that being a new customer I had this type of experience.

From all of the posts I've read on this forum Decware seems to build a quality product. I believe my experience is unique and hope that this latest glitch is just that and that I can start experiencing some of the thrills I've read about.

All of your comments, input, feedback is appreciated.
Fred


Back to top
 
 
  IP Logged
144cubits
Ex Member



Re: SE84C-EX Hum
Reply #6 - 01/14/05 at 19:31:50
 

[quote author=dc007  link=1105725338&amp/0#4 date=1105729309]
welcome Fred...
I too have noticed a more noticeable hum from my EX C, however it is not distracting and does not interfere with the music at all but still in a dead quiet room you do notice it at about 2 feet.
Are you sure your interconnects are good? Unplug all but the speaker cables and see what gives. Do not power the amp up with no speakers hooked up. Also do you have a new set of tubes....possibly a bad tube and lastly is the power source a reliable one?

Good luck
Mike
[/quote]
Thanx Mike for your feedback. I have pretty good interconnects but will try your suggestion, As for tubes I am new to "tube rolling" I'm open to suggestions. My tastes tend more toward a smooth, holographic type of sound. Lastly I must confess I have not invested in any type of power conditioner because this is my "budget sytem" its hooked into a power strip...again I'm open to suggestions ( keep in mind I'm just a po' southern boy).

Thanx again Mike
Fred  
Back to top
 
 
  IP Logged
dc007
Ex Member



Re: SE84C-EX Hum
Reply #7 - 01/15/05 at 16:03:00
 
Fred...do not necessarily need a power conditioner...just be sure the outlet would not be 'noisy' with any equipment. In other words are you confident the outlet and/or power strip would not be contributing to the noise. Heck I use a power strip for components and just plug the amp into the wall myself. Also wasn't suggesting to start rolling tubes but it is always good to have spares just in case one of them may be not quite up to par.
take care
Back to top
 
 
  IP Logged
nodiak
Ex Member



Re: SE84C-EX Hum
Reply #8 - 01/15/05 at 17:08:25
 
   Fred, I have a weird situation in the old building i live in. If the plug (for amp, ext. cord or powerstrip) isn't setting just right in the outlet I get a loud hum. If it is just right no hum. I will eventually replace one outlet to dedicate to system. Maybe similar problem for you ? Good luck, I hope it isn't the ex mod. Don
Back to top
 
 
  IP Logged
Steve_Collins
Ex Member



Re: SE84C-EX Hum
Reply #9 - 01/15/05 at 19:44:17
 
Hi Fed
Sorry to hear of your troubles. I too had an 84C, which i upgraded to a CS and then fitted the EX transformers which revealed a hum in the system. Eddie Vaughan has kindly made some suggestions and as soon as I have the parts I'll wield the soldering iron.
It sounds like you don't do any diy, and with the noise coming from the transformer too I think you should box the amp up and send it back to Steve for a check-up. I feel sure that's what he would want you to do. You need to send it back to establish if it's a problem with the amp or your setup at home. I know you probably don't want to send it back but you'll keep the amp for many years and a few weeks more won't matter in the long run.
Best of luck.
Steve
Back to top
 
 
  IP Logged
144cubits
Ex Member



Re: SE84C-EX Hum
Reply #10 - 01/18/05 at 17:46:45
 
Thanx everyone for the suggestions. I printed out Steve's article on hum and have tried removing the interconnects...hum. Removed the input tube...hum. tried different outlets...hum. Popped out the rectifier...hum. The only thing I've not done is change the output tubes which I really need some suggestions from you guys.

I am loathe to send back the amp just yet I want to try the tubes, and go from there.

Tube rollers I need you! Sad

Fred
Back to top
 
 
  IP Logged
144cubits
Ex Member



Re: SE84C-EX Hum
Reply #11 - 02/02/05 at 19:31:02
 
I gave in and sent the unit back. Awaiting Steve's response.
Fred
Back to top
 
 
  IP Logged
dc007
Ex Member



Re: SE84C-EX Hum
Reply #12 - 02/02/05 at 20:56:42
 
Be sure an post what Steve says on this issue

Regards
Mike
Back to top
 
 
  IP Logged
StingRay
Ex Member



Re: SE84C-EX Hum
Reply #13 - 02/02/05 at 21:06:19
 
I'm also interested since my measured hum level is 2 to 3 times the level specified for this amp.
Back to top
 
 
  IP Logged
144cubits
Ex Member



Re: SE84C-EX Hum
Reply #14 - 02/07/05 at 19:33:39
 
I just got off phone with Steve. Turns out my unit had a bad bypass cap on the output stage. This was generating 4.5mv of hum! Whew! Glad it wasn't my equipment.

I should get it back in a week or so at which point I will hopefully let you guys know that all is well.

Stay tuned.... Roll Eyes
Back to top
 
 
  IP Logged
Pages: 1 2 3 4
Send Topic Print