How to bridge amp to power passive subwoofer?

[maximoiglesias]

Is it posible to bridge an int. amp to power a passive subwoofer?

I have a passive subwoofer powered by an sterero integrated amp in mono mode, can I bridge it to make it more powerful? How do I go about it??

 

[Seth=L]

I don't think your NEC amp has a "bridge" function. All you can do is hope that each channel is capable of delivering the full dynamic power the amplifier can offer. In any case, if you could bridge it your load would become more difficult for the amplifier (say an amplifier is rated 100 watts x 2 @4 ohms, it may only be safely rated for 8 ohm loads when bridged) and your overal output may not increase noticably.

 

[fmw]

Probably not. Very few home audio amplifiers are bridgeable. Most bridgeable amps are from the pro audio industry. For those you just flip a switch and connect the speaker to the correct output.

 

[maximoiglesias]

I was reading some web sites about how to bridge a normal stereo amp but wanted to check out with you guys before doing anything stupid.

Thanks.

 

[wire]

Probably not. Very few home audio amplifiers are bridgeable. Most bridgeable amps are from the pro audio industry. For those you just flip a switch and connect the speaker to the correct output.

I found alot of Home amps are bridgable , not just Pro . Its the recievers there are not very many . Many of you Mid stream Amps willbe bridgable EG . Adcom , Carver , Sunfire , Bryston , Outlaw , Audio Research , NAD to name a few .

 

[maximoiglesias]

amp bridging

I found this and other pages in internet, they are not serious audio specialists but it makes some sense.


By eHow Electronics Editor

Rate: (0 Ratings)

There are many reasons to bridge an amplifier, the main one being to get more power to your speakers and produce a better quality sound. Basically, the process lets you combine the power output of two channels into a single channel. This means that you can get more power to one speaker than you can to two that don't have the bridging in place.

InstructionsDifficulty: Moderate
Step1Read all the paperwork that came with your amp. It's important that you understand as much about your amp as possible before trying to bridge it. Often amplifiers come with a diagram for bridging, which makes your job a lot easier.
Step2Figure out how many channels you need to bridge. If you have a four-channel amplifier, then you'll be bridging it into a two-channel. A two-channel amp will be bridged into a single channel. So the bridged amp should have half the channels of the original amp.
Step3Identify the terminals. For each channel, you should see a positive and a negative terminal. So if your amp has two channels, there should be four terminals total. (A four-channel amp will have eight.) Label each with an identifier on a piece of masking tape, something like A: channel 1, positive; B: channel 1, negative; and so on.
Step4Connect the amplifier to the speaker properly. You should connect the red speaker wire to the terminal labeled A. Then connect the black speaker wire to the terminal labeled D. Then take a short wire and connect terminal B to terminal C to create a bridge between the two channels.
Step5Test your equipment to make sure it works properly.
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[wire]

Is it posible to bridge an int. amp to power a passive subwoofer?

I have a passive subwoofer powered by an sterero integrated amp in mono mode, can I bridge it to make it more powerful? How do I go about it??

You look up the manual to the intergrated amp . Most 2 channel amps have a switch in the back , that is a good indicator . I have a 4 channel amp , that can be bridged and the switch is in the front .
I also know the older , NAD intergrated Amps had the switch in the back and where bridgable ( i had 1 and bridged it ) .

 

[Seth=L]

I found this and other pages in internet, they are not serious audio specialists but it makes some sense.


By eHow Electronics Editor

Rate: (0 Ratings)

There are many reasons to bridge an amplifier, the main one being to get more power to your speakers and produce a better quality sound. Basically, the process lets you combine the power output of two channels into a single channel. This means that you can get more power to one speaker than you can to two that don't have the bridging in place.

InstructionsDifficulty: Moderate
Step1Read all the paperwork that came with your amp. It's important that you understand as much about your amp as possible before trying to bridge it. Often amplifiers come with a diagram for bridging, which makes your job a lot easier.
Step2Figure out how many channels you need to bridge. If you have a four-channel amplifier, then you'll be bridging it into a two-channel. A two-channel amp will be bridged into a single channel. So the bridged amp should have half the channels of the original amp.
Step3Identify the terminals. For each channel, you should see a positive and a negative terminal. So if your amp has two channels, there should be four terminals total. (A four-channel amp will have eight.) Label each with an identifier on a piece of masking tape, something like A: channel 1, positive; B: channel 1, negative; and so on.
Step4Connect the amplifier to the speaker properly. You should connect the red speaker wire to the terminal labeled A. Then connect the black speaker wire to the terminal labeled D. Then take a short wire and connect terminal B to terminal C to create a bridge between the two channels.
Step5Test your equipment to make sure it works properly.
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Amplifier
Trusted Amplifier Answers From Users. Its Free!

It actually doesn't make much sense at all. It's a very poor and vague guide on how to bridge an amplifier that features bridging capability. Just because someone says they can bridge an amplifier doesn't mean "your amplifier" is bridgeable.

Please take a picture of the rear of the NEC integrated amplifier and post it here. There is absolutely no information about that amplifier available online. I will be able to tell you from looking at the rear of the amplifier if it's bridgeable (I find it extremely unlikely considering it's an integrated stereo amplifier). I have yet to see a bridgeable integrated amplifier, but that doesn't mean they aren't out there.

 

[jvgillow]

I have yet to see a bridgeable integrated amplifier, but that doesn't mean they aren't out there.

The two models of Audiosource integrated amps that I have are bridgeable.

 

[fmw]

Before you start bridging amps you should undertand that when you do that the outputs see 1/2 the impedance of the load connected to them. In other words, your 8 ohm speaker system will look like 4 ohms and will draw more current meaning that it will consume a lot of the additional power you created just for that reason. Bridging can be effective but it is always less efficient.

The other thing you should understand is that power, in an of itself, has no bearing on sound quality. If an amplifer clips under the use to which it is put then it simply isn't powerful enough. If it doesn't clip then it is powerful enough. Adding more power than is necessary to prevent clipping accomplishes nothing at all. Amplifier power overhead is only meaningful when you need it and use it. The fellow you quoted above isn't stating things correctly. He says that adding power improves sound quality. It only does that if adding the power prevents an amplifier that was clipping from continuing to clip. In home audio installations clipping is a true rarity.

Bridging an amp may simply cause it to use more current without accomplishing anything either.

If the amp is not designed for bridging then bridging it by rewiring it could and likely will damage it because it will have to operate under impedance loads for which it was not designed.

I guess you can tell I'm not a big fan of bridging amplifiers. I believe that, if you don't have enough power for whatever reason, you need a more powerful amplifer. A bridged one has to deal with that impedance problem.

 

[wire]

It actually doesn't make much sense at all. It's a very poor and vague guide on how to bridge an amplifier that features bridging capability. Just because someone says they can bridge an amplifier doesn't mean "your amplifier" is bridgeable.

Please take a picture of the rear of the NEC integrated amplifier and post it here. There is absolutely no information about that amplifier available online. I will be able to tell you from looking at the rear of the amplifier if it's bridgeable (I find it extremely unlikely considering it's an integrated stereo amplifier). I have yet to see a bridgeable integrated amplifier, but that doesn't mean they aren't out there.

NAD 3100 series are bridgeable intergrated and lower 3000 series was also .
I bridged mine with a NAD amp that was matched , it was very good idea by NAD back then .
I looked also for his NEC on line also couldn't find anything .

 

[wire]

A bridged one has to deal with that impedance problem.

This is good point , but in his situation , powering a sub , he shouldbe ok .
If he was running a speaker hard to drive like electrostatic's , the Bridged amp would have problems powering under 8 ohms and most amps will fry .
Most bridged amps , do not like to run under 8 ohms .

 

[markw]

What answer do you want to hear?

After all, it's your amp to do with as you please. I'll just offer this simple advice :

a) Yes, I know most NAD's and some other amps are bridgable, but they have a switch on the back to facilitate this, as well as the needed circuitry in the front end to split the signal to send one half of the signal to each amplifier.

b) If it doesn't have a bridge switch on the back, I'd be very leery about trying anything that involves connecting two channels together.

c) If that sub is four ohms, be aware that a bridged amp will treat it like a two ohm load, and many amps don't like that.

If you do decide to try it, please let us know how it works out.

good luck.

 

[Shicks18]

+1 to what mark said, he is dead on. Most amps aren't really designed to safely drive 4 ohm speakers in bridged mode. A subwoofer will function fine with a pro amp which can output more power for a lesser cost. Save the Rotels/Nads/B&K/Parasound/Adcoms/etc. for your other speakers.

 

[maximoiglesias]

It actually doesn't make much sense at all. It's a very poor and vague guide on how to bridge an amplifier that features bridging capability. Just because someone says they can bridge an amplifier doesn't mean "your amplifier" is bridgeable.

Please take a picture of the rear of the NEC integrated amplifier and post it here. There is absolutely no information about that amplifier available online. I will be able to tell you from looking at the rear of the amplifier if it's bridgeable (I find it extremely unlikely considering it's an integrated stereo amplifier). I have yet to see a bridgeable integrated amplifier, but that doesn't mean they aren't out there.

My NEC amp is a vintage integrated amp, as far as I know it was never sold in the USA. The whole Authentic Series by NEC was a high quality audio line with excelent reviews in Japan. My amp is a 75 w/ch/rms/8ohm/o.oo1THD/20-20k. My father had it with a pair of Altec Valencias, best sound I have ever heard. (that was in the 70/80s)
There is nothing in the back that suggests it is bridgeable. Just plain inputs/outputs and speaker terminals.

 

[markw]

What does common sense tell you?

There is nothing in the back that suggests it is bridgeable. Just plain inputs/outputs and speaker terminals.

This, to me, would be a pretty good hint...

 

[Seth=L]

This, to me, would be a pretty good hint...

Agreed, if you don't see anything that would suggest it's bridgeable then it's not. When an amplifier is bridgeable it will show you a wiring scheme for your positive and negative terminals, if it doesn't have that it just doesn't do it. You will either have to spend money to get an amp that is (not advised considering you might be able to buy a better powered subwoofer for the money once it's all said and done) or just use one channel or the other. As I mentioned before each channel may be able to deliver the full power, or near too it, that the amps power supply will allow.

 

[maximoiglesias]

Check this out.............

Home Courses Conversation AC Radio AC Blog About Forum





Bridging Amplifiers - sound engineering

niedersteiner writes "
This content is brought to you by Audiocourses dot com

Knowing how bridging amplifiers affects your system can prevent costly equipment failures.

Stereo amplifiers are actually two amps in one chassis, both usually powered from a common power supply. Bridging connects these two amplifiers together to function as one amplifier into one load. (A load is one or any number of loudspeakers connected together.)


There are two ways to connect these amplifiers to each other, parallel or series. Parallel bridging doubles the current available to the load, series bridging doubles the voltage on the load. It is the series connection that is most commonly used when "mono bridging" your amp.

When voltage is doubled the power goes up four times on the same load. Let's illustrate this point by using one of my old SAE P50's as an example. This amp is conservatively rated at 50W per channel into 8 ohms, producing a total of 100W into two 8 ohm loads (50W from each channel). When this amp is bridged (it is now mono) it will produce 200W into one 8 ohm load.

Connecting the two 8 ohm loudspeakers together in parallel gives you a net load of 4 ohms. The bridged amp will now try to dump 400W into this load (200W to each loudspeaker). Each amplifier section "sees" this as a load of only 2 ohms (half of the 4 ohm net load), which is very nearly a dead short. The current flow becomes 4 times what it would normally be into a single 8 ohm loudspeaker (one per channel in stereo mode) and the amp tends to heat up trying to deliver this much current.

Also consider what your speakers must now contend with. This same amp that was once producing a comfortable 50W (with 3dB headroom) is now giving it 200W. Apply these ratios to amplifiers of more power (a 100W per channel stereo amp becomes a 400W series-bridged amp) and loudspeakers soon become overwhelmed.

Unless you are comfortable applying these numbers in your system, approach series bridging with caution.

Original Page.

Copyright © 2001 Anton Niedersteiner. All rights reserved.
"








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[markw]

So, what's your point?

I thought this was a done deal. Apparantly not.

Apparantly, you think they know more than we dummies do.

Just keep in mind these lines from the article : "Knowing how bridging amplifiers affects your system can prevent costly equipment failures."

and : "Unless you are comfortable applying these numbers in your system, approach series bridging with caution."

You may want to fully comprehend these lines.

I guess all that's left is for you to man up and go for it now, right?

Do let us know how it works out for ya.

 

[maximoiglesias]

Just to make sure I'll try with an old Goldstar integrated amp I have around.
I will let you know, but please have in mind that I would never consider you guys dummies, if not I would not be asking your advice.