Monitor 5B Impedance

[monitor5b]

I have a pair of Monitor 5Bs that I purchased new in late 1989. I just noticed that the owner's manual states the nominal impedance as 4 ohms. This seems really low for a $225 speaker. The same manual shows all of the smaller Monitors as well as the 7C also at 4 ohms. The 10B and 11 have 6 ohm ratings. Is this correct? If it is, there's some pretty expensive (to me) equipment out there that can't drive these things.:confused:

[nadams]

The monitor 5's on polks website shows as 8 ohms. Actually, most of the smaller Monitor's were 8 ohm. Even the monitor 10's and 12's are 8. You'd think that the manual would be accurate, though.

[Tour2ma]

There are a number of inconsistancies between the vintage website and owner manual info... and not just in the Monitor line. Trust the manual...

My original 10's are nominal 6-ohm per the manual. 6-ohm is not that difficult of a load to drive.

A 4-ohm load is tough, but Mon 5's are not meant to be driven to concert hall levels (neither are the 7's for that matter). You must be aware of this since you aren't mentioning a problem and have owned the 5B's for 15+ years...

If drive them you must, there's a great deal of inexpensive (to me) amps out there on the used market that can handle them... Carver for one with several models under $300.

Welcome to the Club...

[waylyn5945]

Originally posted by nadams
The monitor 5's on polks website shows as 8 ohms. Actually, most of the smaller Monitor's were 8 ohm. Even the monitor 10's and 12's are 8. You'd think that the manual would be accurate, though.

My Monitor 10s actually measure 5.2 ohms with a Fluke 87 III. And I drive them with a 1976 hk-430 rated at 25 wpc with no problem.

[RuSsMaN]

Put your multimeter on the posts.

If you get around 3.2 ohm, they are 4ohm nominal. If you get around 5.8-6.3 ohm, they are 8ohm nominal.

Cheers,
Russ

[Tour2ma]

Good info Russ...

So waylyn's 5.2 reading would correspond to the 6-ohm nominal... Yes? (ah, the wonders of interpolation...)

[monitor5b]

4.2 ohms on both. How'd you know I had a multimeter?