2. amps-preamps
  3. 1250637079

Vibrating Woofer, old tubes?

I have a dual mono tubed phono section that even has an active tube line input for a cd player. Now, I have a little problem with it, and I am not sure what the cause is.

When I open the volume wide open it causes my speakers to vibrate and gives and it hums in strange way. The weird thing: It goes away after I let the unit heat up for a couple of hours, usually. After using it for a couple of hours I can open the volume pot wide open, I mean wide open and it is as quite as a Church.

Is the thing scrap metal or is it something easy to fix?

Can it just be the tubes needing to be replaced?

I am a little freaked out about, becuase I really do love the item and have no desire to purchase another tube phono section or even tube pre at all; though I would like to be able to use it without damaging my loudspeakers. I will be getting a new pair any day now and I am a little worried. Please help me out guys, thanks a million.
dfelkai
dfelkai OP
89 posts
 
This might be a stupid question, but suppose that everything is in working order, all else constant. Does doing so change the character of the sound?

Yes this is certainly an old unit, and that could be a solution. So who manufactures an excellent filter cap? I was thinking of doing it myself. Despite being a beginner I have done a lot of soldering and work with basic electronics, like RC cars when I was a kid. I understand that I might be a little out of my league with tube equipment though. Perhaps this might be better left to an expert.

So suggest an excellent parts manufacturer, and I will check the specs on the unit and get the best part possible put in there. Thanks for the heads up. \

Does this mean you have actually heard of this unit? Very unusual. At the local shops when they ask me what I am using I ordinarily receive blank stares upon my reply.
atmasphere's avatar
atmasphere
11,784 posts
 
You have bad filter capacitors in the power supply. This condition is called 'motorboating' and can be affected by temperature and the length of time that the unit is one.

It is something that needs service! I would not operate this unit until this is fixed. If left unattended, you run a good risk of frying the power transformer! Trust me, that is a very unpleasant experience.
dfelkai OP
89 posts
 
Where can I order some good quality filter caps, please post a link.
dfelkai OP
89 posts
 
Thanks for the heads up, I really appreciate it. If you are right, and I think you are, then you have saved me a an immense amount of headache.
rodman99999
6,125 posts
 
Some nice, high quality caps can be purchased here(other manufacturers can be found, bottom of page):(http://www.partsconnexion.com/t/catalog/CapacitorsElectrolytic.html) or here: (http://www.percyaudio.com/Catalog.pdf) I've found both suppliers to be very reliable and prompt. The salesmen at your local shops probably used to sell sneakers or change oil for a living, and know little about audio(outside of what they've read on a component's blurbsheet). That's been my experience with the majority of salepersons I've encountered over the decades.
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