Problem with Definitive tech Prosub100TL

hello,
i just bought a brand new definitive tech Prosub 100TL
subwoofer.
i noticed that whenever the subwoofer is turned on/off
there is a loud thump from the sub even with the LFE
cable disconnected.
why is this?is this normal? if not, how do i eliminate
it?
will i risk damaging the sub if i continue using it as
it is or do all definitive tech subs share this trait.

Sachi

Quote:

---

Originally Posted by sachi

hello,
i just bought a brand new definitive tech Prosub 100TL
subwoofer.
i noticed that whenever the subwoofer is turned on/off
there is a loud thump from the sub even with the LFE
cable disconnected.
why is this?is this normal? if not, how do i eliminate
it?
will i risk damaging the sub if i continue using it as
it is or do all definitive tech subs share this trait.

Sachi

---

I believe this is the powered amp in the sub doing a "hard" power-up. I don't believe you can eliminate it.

---Dave

Quote:

---

Originally Posted by sachi

hello,
i just bought a brand new definitive tech Prosub 100TL
subwoofer.
i noticed that whenever the subwoofer is turned on/off
there is a loud thump from the sub even with the LFE
cable disconnected.
why is this?is this normal? if not, how do i eliminate
it?
will i risk damaging the sub if i continue using it as
it is or do all definitive tech subs share this trait.

Sachi

---

All definitive subs do not share this trait. The only way I was ever able to get my prosub 100tl to make a loud thump (unintentionally) was when i had to turn off my circuit breaker (old apartments) and then turn it back on when a circuit tripped.

i got ur mail chimera. i wrote to definitive and this is what Chet said.
"
Thanks for your recent email to Definitive Technology. The "thumping"
sound
heard when a ProSub100TL first receives electricity and stops receiving
electricity (or when it is turned on and off) is normal. It's not
"dangerous" and won't cause any harm to your subwoofer (I'm sure it's
annoying though.)

I'd recommend plugging your ProSub100TL into an "unswitched" outlet
that
receives AC power all the time (and leaving it turned on). This way
you
won't hear any popping or thumping when you turn your system on or off.
(Its auto on/off circuit will quietly turn the amplifier on and off.)

(The amplifier used in the ProSub100TL has a unique power supply that
draws
its power from the AC outlet as needed. It doesn't have a traditional
transformer and it doesn't' store its power on board. A draw back of
this
unique design is that it produces a transient when it first receives
electricity and when it stops receiving electricity.)

If you need any other information, please email me at
cpelkowski@definitivetech.com.

Thanks,
Chet Pelkowski
Definitive Technology"

now this makes me think that either Chet is wrong and u are right or ur sub, pardon me for saying this, is not working right.
please clarify. any more Prosub owners who can comment on this?
thanks

My ProSub80 does the same thing, although I would not say it is loud or disconcerting. I emailed them and they told me to leave the sub on all the time. I only unplug it when I won't be using it for a while (vacations, business trips). I haven't gone away in a while so I forgot about it, but it's a good thing you brought it up again. I'd like to know more as well...

Chet is right. I just don't hear a LOUD THUMP when my subwoofers turn on. At most I hear a click out of a couple, but it's barely audible.

well mine is audible. its like hearing a kick drum although in a more uncontrolled way.
i tried connecting to other sockets and its the same thing.