[LGLA]

Hello all, if anyone can help. I am curious, I have an Onkyo two channel from '99 or
'00 (I know it is not 'high-end' please forgive) very basic. It does 50wpc into 8ohm or
105wpc into 4ohm so I picked up a pair of M&K 4ohm speakers used, very accurate,
as an upgrade but I need a subwoofer for them. They have two mids and a tweeter,
not enough bass.

Problem is, I don't know if a powered sub can take the 50 or 105 wpc into it's own
electronics as a pre-amped signal and then power the woofer? Because this receiver
does not have a pre-amp output for a sub. Is it safe to do so, or should I look for a
good passive sub?

Any help is much appreciated, and product recommendations are quite welcome.

--
Alex in SoCalifornia
cravdraa at yahoo dot com

[David Nebenzahl]

On 2/20/2009 3:20 PM LGLA spake thus:

Problem is, I don't know if a powered sub can take the 50 or 105 wpc
into it's own electronics as a pre-amped signal and then power the
woofer? Because this receiver does not have a pre-amp output for a
sub. Is it safe to do so, or should I look for a good passive sub?

But it does have a preamp output for tape out, doesn't it? Seems like
you ought to be able to use that signal.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

[Peter Irwin]

David Nebenzahl wrote:
On 2/20/2009 3:20 PM LGLA spake thus:

Problem is, I don't know if a powered sub can take the 50 or 105 wpc
into it's own electronics as a pre-amped signal and then power the
woofer? Because this receiver does not have a pre-amp output for a
sub. Is it safe to do so, or should I look for a good passive sub?

But it does have a preamp output for tape out, doesn't it? Seems like
you ought to be able to use that signal.

Tape out is normally at a fixed level instead of being controlled
by the volume control. An easy solution is to use a voltage divider in
parallel with the speakers. A 47 ohm and a 470 ohm resistor in series
with each other with the output to the sub being taken from each end
of the 47ohm resistor should give you a 20dB pad and get you about where
a preamp output would be. 2 watt resistors will be fine.

Peter.
--

[Peter Larsen[_3_]]

LGLA wrote:

Hello all, if anyone can help. I am curious, I have an Onkyo two
channel from '99 or '00 (I know it is not 'high-end' please forgive)
very basic. It does 50wpc into 8ohm or 105wpc into 4ohm so I picked
up a pair of M&K 4ohm speakers used, very accurate, as an upgrade but I
need a subwoofer for them. They have two mids
and a tweeter, not enough bass.

Problem is, I don't know if a powered sub can take the 50 or 105 wpc
into it's own electronics as a pre-amped signal and then power the
woofer? Because this receiver does not have a pre-amp output for a
sub. Is it safe to do so, or should I look for a good passive sub?

Use the headphone output.

Any help is much appreciated, and product recommendations are quite
welcome.

Kind regards

Peter Larsen

[Peter Larsen[_3_]]

David Nebenzahl wrote:

On 2/20/2009 3:20 PM LGLA spake thus:

Problem is, I don't know if a powered sub can take the 50 or 105 wpc
into it's own electronics as a pre-amped signal and then power the
woofer? Because this receiver does not have a pre-amp output for a
sub. Is it safe to do so, or should I look for a good passive sub?

But it does have a preamp output for tape out, doesn't it? Seems like
you ought to be able to use that signal.

And how do you propose to get hte sub to follow the volume control?

Kind regards

Peter Larsen

[Peter Larsen[_3_]]

Peter Irwin wrote:

David Nebenzahl wrote:
On 2/20/2009 3:20 PM LGLA spake thus:

Problem is, I don't know if a powered sub can take the 50 or 105 wpc
into it's own electronics as a pre-amped signal and then power the
woofer? Because this receiver does not have a pre-amp output for a
sub. Is it safe to do so, or should I look for a good passive sub?

But it does have a preamp output for tape out, doesn't it? Seems like
you ought to be able to use that signal.

Tape out is normally at a fixed level instead of being controlled
by the volume control. An easy solution is to use a voltage divider in
parallel with the speakers. A 47 ohm and a 470 ohm resistor in series
with each other with the output to the sub being taken from each end
of the 47ohm resistor should give you a 20dB pad and get you about
where a preamp output would be. 2 watt resistors will be fine.

A much better alternative.

Peter

Kind regards

Peter Larsen

[DC[_2_]]

Peter Larsen wrote:
LGLA wrote:

Hello all, if anyone can help. I am curious, I have an Onkyo two
channel from '99 or '00 (I know it is not 'high-end' please forgive)
very basic. It does 50wpc into 8ohm or 105wpc into 4ohm so I picked
up a pair of M&K 4ohm speakers used, very accurate, as an upgrade but I
need a subwoofer for them. They have two mids
and a tweeter, not enough bass.

Problem is, I don't know if a powered sub can take the 50 or 105 wpc
into it's own electronics as a pre-amped signal and then power the
woofer? Because this receiver does not have a pre-amp output for a
sub. Is it safe to do so, or should I look for a good passive sub?

Use the headphone output.

Any help is much appreciated, and product recommendations are quite
welcome.

Kind regards

Peter Larsen



Or, find a powered subwoofer that accepts speaker level as well as line
level input. Lots of them have this - from an Energy ESW-8 @ @ CAD$299
to Velodynes and on up. Then, run from your speaker outs on the
receiver into the subwoofer, then from the subwoofer to the M&Ks.
Depending on the subwoofer, there may also be a crossover (hopefully
adjustable) in the subwoofer that'll remove the low frequencies from the
signal sent on to the M&Ks.

DC

[David Nebenzahl]

On 2/20/2009 6:46 PM Peter Irwin spake thus:

David Nebenzahl wrote:

On 2/20/2009 3:20 PM LGLA spake thus:

Problem is, I don't know if a powered sub can take the 50 or 105 wpc
into it's own electronics as a pre-amped signal and then power the
woofer? Because this receiver does not have a pre-amp output for a
sub. Is it safe to do so, or should I look for a good passive sub?

But it does have a preamp output for tape out, doesn't it? Seems like
you ought to be able to use that signal.

Tape out is normally at a fixed level instead of being controlled
by the volume control.

Doh! Hadn't thought that through. Your "pad" idea sounds good. (Is that
an "L" pad or a "T" pad?)


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

[Dave]

"LGLA" wrote in message
...

Hello all, if anyone can help.

Most active (powered) subs have both a line-level input and a speaker-level
input. If you choose one that doesn't have the high-level input option, you
can make a very very inexpensive ($5) pair of attenuators which will drop
your speaker level outputs down to line level. It's I think two or three
resistors per lead.

Whoever suggested using the tape out, that's a great idea... if you like
adjusting the volume on the back of the subwoofer every time you adjust the
main volume. Tape monitor output is not controlled by the preamp volume.

My opinion is that you'll be better off with a powered sub, or else you'll
need a separate amp and an external crossover for a passive sub. The plate
amps which come with powered subs are generally pretty hefty, mine is 270W
RMS and I've seen them as high as 1000W.

Dave

[Richard Crowley]

"LGLA" wrote ...
Hello all, if anyone can help. I am curious, I have an Onkyo two channel
from '99 or
'00 (I know it is not 'high-end' please forgive) very basic. It does
50wpc into 8ohm or
105wpc into 4ohm so I picked up a pair of M&K 4ohm speakers used, very
accurate,
as an upgrade but I need a subwoofer for them. They have two mids and a
tweeter,
not enough bass.

Problem is, I don't know if a powered sub can take the 50 or 105 wpc into
it's own
electronics as a pre-amped signal and then power the woofer? Because this
receiver
does not have a pre-amp output for a sub. Is it safe to do so, or should
I look for a
good passive sub?

Any help is much appreciated, and product recommendations are quite
welcome.

If the powered sub doesn't have speaker-level inputs (some do), then
you can use a simple passive "pad" to knock the speaker-level signal
down to line-level to feed into the subwoofer.

For example, here is one that costs less than $ 1.. .
http://www.parts-express.com/pe/show...number=269-050
This particular one has connectors for automobile use, but those can be
cut off and used with any home system.

My preference would be to NOT use a passive subwoofer for several
reasons.

[David Nebenzahl]

On 2/23/2009 9:56 AM Dave spake thus:

Whoever suggested using the tape out, that's a great idea... if you like
adjusting the volume on the back of the subwoofer every time you adjust the
main volume. Tape monitor output is not controlled by the preamp volume.

That was me, who felt pretty stupid after realizing just what you said.

But on second thought it might not be a bad idea. Think about it: a lot
of people listen to music at pretty much the same level all the time,
and some folks rarely, if ever, even touch the volume control. So
assuming the subwoofer has a level control, it might be OK to just "set
it and forget it". All depends on how the O.P. listens to music.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair