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
 
how much do you think I should be paying for the labour? I talked to a local tube expert today, he will give me an estimate a couple of days after I drop off the unit. I don't want to overpay, help me not get ripped off. Thanks again.
atmasphere's avatar
atmasphere
11,784 posts
 
Dfelkai, most shops in the US will charge about $75-$80.00 per hour. That allows them to pay the technician and their overhead. Filter caps do not take a long time to change, and this is entirely off the top of my head, so unless there is something really unusual about this preamp I would guess that 2 hours is all that is needed.

Without even seeing the unit, that's the best I can come up with- diagnosing at a distance has its problems :)
swampwalker's avatar
swampwalker
5,138 posts
 
What you may find is a "bench charge" or a diagnostic charge. Maybe $30-50 to be applied against repair if you go ahead. some shops will have a 1 or 2 hr minimum. Lots of variability in terms of minimum charges, etc. If $75 or $80 seems high, my plumber has a $100 minimum! 'Course his family is the biggest real estate holder in the most exclusive suburb in my region!!!
dfelkai OP
89 posts
 
Bench tested absolutely flawless!! I am happy, it was the tubes, got a wack of news ones experimented with rolling and problem is 100% fixed. I am happy to say the least. Thanks for helping me out, guys.
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