Volume Controls

[derekwwww]

Can someone explain to me the difference between impedance matching and non impedance matching in wall volume controls? If a guy wants to have a volume between the amp and speakers which would you use?

Thanks

 

[annunaki]

Impedance matching volume controls allow the use of more than two speakers on one volume control. Once could run four 8 ohm speakers on the control in parallel, yet the receiver/amplifier would only see an 8 ohm load. They work well for multi-source multi-zone keypad systems.

Impedance matching controls are also useful when running an impedance matching system to utilize a single amplifier for the entire whole house system.One can run four speakers (or possibly more) on each volume control, have in upwards of 6 different zones or more, run them into an impedance matching unit from NXG, Russound, etc., and power it all off of one amplifier around 200 watts rms per channel or so.

One could also skip the impedance matching unit and wire all of the vc in a series parallel configuration, or some other option, for the desired impedance. The reason the impedance matching units would be important here is the configurations for wiring can be done prior to the installation for proper amplifier choice.

 

[TLS Guy]

Can someone explain to me the difference between impedance matching and non impedance matching in wall volume controls? If a guy wants to have a volume between the amp and speakers which would you use?

Thanks

A non impedance volume control is fine if you are controlling one set of speakers, one left and one right.

However if you have multiple sets of speakers to control, the the impedance would drop, and you blow up your amplifier.

An impedance matched control comes in carious forms. The simplest allow for the inclusion of series and shunt resistor taps to keep the resistance constant. You need to follow the instructions carefully.

More complex types have variable transformers to keep the impedance to the amp constant.

There are now even digital types around in some systems.

 

[derekwwww]

Ok because I know 10 or 15 years ago the volume controls they had were had on amps.... correct? I am just controlling one pair of speakers so guess I wont need impedance matching.... Thanks

 

[BMXTRIX]

That's correct. If you are matching one speaker up to one channel of an amplifer you are likely not going to have any issues at all.

Even two speakers hooked up, producing a 4 ohm load, is typically fine with most decent amplifiers.

It's when you have 3 or 4 or more speakers hooked up that things start getting ridiculous and you really want the impedence matching VCs.

I'm a big fan of one channel to one speaker (or two) in each room. Costs a bit more, but incredibly reliable.