bridging integrated amplifier


Hi, I have a NAD 7220PE. Would it be safe to wire the the left and right channels to bridge to a single 8ohm speaker?
Thanks!
rome2000
no.
Your receiver is not designed to be bridged, and doing it the way you want is NOT the way bridged amps are wired anyway.
Connecting both channels together will almost certainly destroy your receiver.

If you want to have a single source from both channels, the only resonable way to do it is stick both speakers in the same place.
Thanks, that's good to know!
" Connecting both channels together will almost certainly destroy your receiver."

Depending on some other factors but this is how our stereo amp work in fully balanced monoblock mod and no amplifiers were destroyed yet but I would not bet against human creativity - one day I surely will be surpised!

Most probably will be either near silence or actually somewhat distorted sound: the last depends on parts tolerance in both channels which is rather expensive or very, very expensive.

The best if OP will ask manufacturer in question directly - they have great name and surely will advise professionally

All The Best.
Simon
The bridging wiring technique to take the positive from the receiver's right channel and connecting to the positive terminal on the speaker, then take the negative from the receiver left channel to the speakers negative terminal. The speaker is 8 ohm so the load should drop to 4ohms. I'll reach out to NAD also...
01-13-12: Rome2000
The bridging wiring technique to take the positive from the receiver's right channel and connecting to the positive terminal on the speaker, then take the negative from the receiver left channel to the speakers negative terminal. The speaker is 8 ohm so the load should drop to 4ohms.
That is not bridging, nor is connecting the outputs of the two channels together which is what I believe Simon was addressing.

I suspect that your NAD, like most amplifiers or receivers that do not have balanced outputs, has the negative output terminals of both channels connected together internally. Therefore the connections you are proposing would make no difference compared to connecting the speaker to the output terminals of one channel.

Bridging as properly defined (for an amplifier having unbalanced outputs) involves connecting the speaker between the two positive output terminals, with no connection to the negative terminals, and having one channel of the amplifier process a signal that is inverted with respect to the one being processed by the other channel. That will usually result in a large increase in the amount of power that can be delivered into an 8 ohm load, because as a rough approximation it would double the range of output voltages that the amplifier can provide. However, it is not usually practicable to do that unless the amplifier design specifically provides for it, and according to the manual your NAD does not.

Regards,
-- Al
Rome2000, contacting Nad sounds like a good idea as mentioned above, if you really think it can be done. But, bridging your receiver would not be a good idea in my opinion either. If it would work, it would change the impedance to 16 ohms, not 8 ohms. Definitely don't try it, without asking NAD first.

Receivers don't normally have do not have balanced outputs to my knowledge, and are not capable of bridging.

Bridging a lot of amplifiers is not an option either.

I've never seen a receiver that has outputs that can be bridged, at least that I can remember. A company that makes amplifiers commonly will tell you the option and mention its connections in the manual, but I don't see that in your manual, that's available to everyone on the net. A lot will print it on the amp (receiver in this case) by the speakers connections.

Maybe Spectron has some unique designed receivers.
If you want both channels output through a single speaker rated at 8 ohms, you could just connect it conventionally via one set of speaer terminals, then set NAD's speaker impedance selector to 8 ohms, and then press the "Mono" selector button on the front right panel of the receiver, to merge stereo signals into a single mono output.
Do you actually need to double the power output, anyway?

01-13-12: Sandstone
If you want both channels output through a single speaker rated at 8 ohms, you could just connect it conventionally via one set of speaer terminals, then set NAD's speaker impedance selector to 8 ohms, and then press the "Mono" selector button on the front right panel of the receiver, to merge stereo signals into a single mono output.
Do you actually need to double the power output, anyway?
Sandstone (Answers | This Thread

Doing this will let the receiver sort of act as a 8 ohm monoblock amp from the way I view the schematic. I don't see it as acting a bridged amp.
Thanks for all the input, I'm following Sandstone's advice. My setup is for my home office and I have limited desk space. I run 2 small speakers next to each other, but I have single large bookshelf that can take up the same space and would give me more low end. I was looking to take advantage of the power options from the stereo but rather not risk off wiring.
but I have single large bookshelf that can take up the same space and would give me more low end. I was looking to take advantage of the power options from the stereo but rather not risk off wiring.
Rome2000 (Threads | Answers | This Thread)

Make sure the speaker is rated at 8 ohms for the 8 ohm setting. If it is a 4 ohm speaker, use the 4 ohm setting. Otherwise, the one channel it's running on can overheat and get damaged. Using the mono setting will make sure you hear both left and right channels, through the single speaker.
Rome,
One additional thought - if your single speaker is able to be biwired - that is, has separate sets of connectors for low-frequency and high-frequency ranges, you should actually be able to connect both "channels" of your receiver while in mono mode. Remove the speaker's jumpers and then conventionally connect "left channel" outputs to one set of terminals and then "right channel" outputs to the other. Both channels would actually be outputting in mono mode. Not sure whether this will actually deliver more power or better dynamics but it may be worth a try.
Best,