Does bridging amp create higher noise floor?

[Lisa Forster]

I am currently tuning my latest iteration of a system that has consisted of
the same gear for years. In this install I have bridged the four main
channels of a Soundstream Rubicon 805 to stereo for the front stage. It has
come to my attention that the system noise floor seems incredibly high
(thermal noise). Can this be a function of bridging the amp? I will be
taking another look at the gain structure to be certain I haven't made a bad
adjustment but still wonder if noise is just the nature of the beast when
bridging. The source of the system is Sony's CDX-C910 fed optically to
their XDP-210 digital equalizer. Drivers are all Boston Acoustics Pro
series. Thanx for your attention and replies.


Roger Forster

[Mark Zarella]

> I am currently tuning my latest iteration of a system that has consisted
of
> the same gear for years. In this install I have bridged the four main
> channels of a Soundstream Rubicon 805 to stereo for the front stage. It
has
> come to my attention that the system noise floor seems incredibly high
> (thermal noise). Can this be a function of bridging the amp?

Usually not, unless it's very poor quality or not healthy. I'd begin by
triple checking all amplifier and source grounds. Yes, the grounds can
still be the culprit even if you don't hear the noise when not bridged.

[Paul Vina]

I agree with Mark. The Rubicon amps were the best SS ever made and I used
them in plenty of competition cars with zero noise. Good luck!


Paul Vina



"Mark Zarella" > wrote in message
...
> > I am currently tuning my latest iteration of a system that has consisted
> of
> > the same gear for years. In this install I have bridged the four main
> > channels of a Soundstream Rubicon 805 to stereo for the front stage. It
> has
> > come to my attention that the system noise floor seems incredibly high
> > (thermal noise). Can this be a function of bridging the amp?
>
> Usually not, unless it's very poor quality or not healthy. I'd begin by
> triple checking all amplifier and source grounds. Yes, the grounds can
> still be the culprit even if you don't hear the noise when not bridged.
>
>

[sanitarium]

when bridging many (but not all) amps into 4 ohms damping factor
decreases, stereo separation decreases, S/N ratio decreases and
sometimes THD increases. BUT it should not be noticeable, its all in
VERY small increments. Especially with that amp. Curious... do those
have an Impedence optimization switch on the bottom? I know older SS
amps did. Might want to look into that although I doubt thats the culprit.
Check all your grounds including the headunit, scrape/dremel any paint
off the sheetmetal to obtain a good metal/metal contact.

as a last resort, Might want to remove the amp cover panel and double
check its internal grounds, make sure the screws are tight and ground
straps (if any) are secure. note this will void any warranty.

Garrett

Lisa Forster wrote:
> I am currently tuning my latest iteration of a system that has consisted of
> the same gear for years. In this install I have bridged the four main
> channels of a Soundstream Rubicon 805 to stereo for the front stage. It has
> come to my attention that the system noise floor seems incredibly high
> (thermal noise). Can this be a function of bridging the amp? I will be
> taking another look at the gain structure to be certain I haven't made a bad
> adjustment but still wonder if noise is just the nature of the beast when
> bridging. The source of the system is Sony's CDX-C910 fed optically to
> their XDP-210 digital equalizer. Drivers are all Boston Acoustics Pro
> series. Thanx for your attention and replies.
>
>
> Roger Forster
>
>

[Kevin McMurtrie]

In article >,
"Lisa Forster" > wrote:

> I am currently tuning my latest iteration of a system that has consisted of
> the same gear for years. In this install I have bridged the four main
> channels of a Soundstream Rubicon 805 to stereo for the front stage. It has
> come to my attention that the system noise floor seems incredibly high
> (thermal noise). Can this be a function of bridging the amp? I will be
> taking another look at the gain structure to be certain I haven't made a bad
> adjustment but still wonder if noise is just the nature of the beast when
> bridging. The source of the system is Sony's CDX-C910 fed optically to
> their XDP-210 digital equalizer. Drivers are all Boston Acoustics Pro
> series. Thanx for your attention and replies.
>
>
> Roger Forster

You're doubling the power and that doubles the noise too. You'd have
the same problem if you used an amp with twice as much power.

Minor noise problems are the hardest kind to track down. They aren't
easily heard on a handheld amplified speaker. Make sure all of the
gains are aligned so everything clips at the same time. After that
you'll have to track down the problem by powering components on and off.

[Paul Vina]

SS stopped using the load switches AGES ago. I think the last to use them
were the old MC series. The References and the Rubis definitely didn't.


Paul Vina



"sanitarium" > wrote in message
...
> when bridging many (but not all) amps into 4 ohms damping factor
> decreases, stereo separation decreases, S/N ratio decreases and
> sometimes THD increases. BUT it should not be noticeable, its all in
> VERY small increments. Especially with that amp. Curious... do those
> have an Impedence optimization switch on the bottom? I know older SS
> amps did. Might want to look into that although I doubt thats the
culprit.
> Check all your grounds including the headunit, scrape/dremel any paint
> off the sheetmetal to obtain a good metal/metal contact.
>
> as a last resort, Might want to remove the amp cover panel and double
> check its internal grounds, make sure the screws are tight and ground
> straps (if any) are secure. note this will void any warranty.
>
> Garrett
>
> Lisa Forster wrote:
> > I am currently tuning my latest iteration of a system that has consisted
of
> > the same gear for years. In this install I have bridged the four main
> > channels of a Soundstream Rubicon 805 to stereo for the front stage. It
has
> > come to my attention that the system noise floor seems incredibly high
> > (thermal noise). Can this be a function of bridging the amp? I will
be
> > taking another look at the gain structure to be certain I haven't made a
bad
> > adjustment but still wonder if noise is just the nature of the beast
when
> > bridging. The source of the system is Sony's CDX-C910 fed optically to
> > their XDP-210 digital equalizer. Drivers are all Boston Acoustics Pro
> > series. Thanx for your attention and replies.
> >
> >
> > Roger Forster
> >
> >
>

[Mark Zarella]

> You're doubling the power and that doubles the noise too.

Nuh uh!

[Kevin McMurtrie]

In article >,
"Mark Zarella" > wrote:

> > You're doubling the power and that doubles the noise too.
>
> Nuh uh!
>
>

Oops, I meant to say quadruple. I posted too early in the morning.

Of course you can always buy higher gain equipment with a better SNR,
but you need to know exactly where the noise is coming from first.
Commonly one part of the stereo system is to blame for most of it.

[Mark Zarella]

> > You're doubling the power and that doubles the noise too.
> >
> > Nuh uh!
> >
> >
>
> Oops, I meant to say quadruple. I posted too early in the morning.

Not that either. There's a noise component that does quadruple, and there's
a noise component that remains the same. And there are noise components
that do something in-between.