monoblock amplifiers

why do monoblocks have two sets of terminals? are they bridged internally? and if wiring one set of wires to them do you run them in one channel or "bridge" the two channels?

They use 2 sets of terminals only for ease of installation.  Both positive terminals are electrically connected inside the amp.  Same for both negative terminals. 

so if you put say a two ohm load into each channel internally it will be bridged into a one ohm load in one channel?

There is only one channel.  But yes if you connect 2 separate 2 ohm loads to the amp, since the terminals are internally paralleled, the load on the amp will be 1 ohm.

Monoblock amps are usually 2ohm stable only, unless stated D-Class which are 1ohm stable, there is a lot of companies out there now using this heading is a selling tool, just be sure to read what the amp can do, and everything above in the posts are right as well.

-------------
Chadillac

There are many class D amplifiers that are not 1 ohm stable.

Absolutely correct, there is alot of D-Class amps that are not 1ohm stable, thats why I included the  just be sure to read what the amp can do, line in the post,thx.

-------------
Chadillac

so if an amp is one ohm stable i can put a two ohm load into each set of termials and it will be at one ohm? and also if running just one set of wire do they just go to one or the other set of terminals or do you bridge them?

THERE IS NO BRIDGING. Bridging connects two channels of a stereo amplifier to a single individual load, in a mono configuration. You have one channel. You cannot bridge one channel. Just forget that word, for now. They are parallel connections, just done for you inside the amplifier for convenience.

If you have two identical (just for example) 4 ohm woofers, you simply wire one of them to one set of +/- terminals on the amplifier, and you wire the other woofer to the OTHER set of +/- terminals on the amplifier. That is not a bridge, it is a parallel connection, and presents the amplifier a 2-ohm load.

Just parallel. The outputs of the amplifier just has two positive and two negative electrical connections for the installer to connect to.

If you have only one 4-ohm woofer, you can connect it to EITHER set of +/- connections on the amplifier, and be done. This is a 4 ohm load, no matter HOW you mix/match the positive terminals or the negative terminals.

If you have a DVC woofer, you can connect one voice coil to one set of terminals, and the other to the other set of terminals, it's the same thing as doing it on the woofer itself, it just parallels the voice coils.

ok awsome thank you! let me see if i got this right, so if i have a D2 sub and wired each coil into a set of terminals on an amp the amp would be seeing one ohm right?

Yes.

You know how they say that there is always at least one exception to every rule.  Following is some info on on a Mono amp that is actually 2 amps strapped together.  It can be run at 1 ohm per amp, or it can be run at 2 ohms strapped. 

https://www.the12volt.com/installbay/forum_posts.asp?tid=119579&KW=massive+3000#584954

thanks a lot guys! this helps immensly!