Thiel speakers--can you power them with reciever?

Or do they really need a separate amp?

I am getting the bug to make a speaker change(for my front L/R speakers), and from what I read, it seems like a used set of Thiels may be up my alley in terms of sound characteristics.

But, looking at their rated specs, they are rated at 4 ohms, with a minimum of 3 ohms, and have fairly low sensitivity at 87Db.

I'm also looking at used Vandersteen, Eggleston, Merlin. It seems like most of these have similar ratings to the Thiels.

Any thoughts? I am currently running my 5.1 system off a 130wpc receiver, but I do have a 5 channel power amp I could use. The receiver is not known for having much output into 4 ohm loads.
Whether you choose the Theils or any one of the other speakers that you mentioned, they deserve better than what the receiver can do.

So, you might want to get the multi channel amp ready....
Your receiver might overheat causing the outputs to blow/short ,possibly passing a lot of voltage to the Theil's blowing them out.Power amps that can drive 4 ohm speakers would on my priority list.
A good B&K or higher end Denon may be able to push them. Thiels will kill a cheaper yamaha or similar. Keep in mind that all Thiels are not equal. A pair of 1.5's will be easier to push than an older pair of 2 or 3's.
The Thiels will bring your receiver to its knees and make it cry for its mamma. You need a separate amplifier with sufficient testicular fortitude to drive the Thiels.
My Sony 5-channel amp rated at 140wpc sounds substantially less punchy and flat in comparison to other good 60-100W audiophile grade amps. Power ratings on AV amps and receivers are often over-rated with higher-end units an exception.
Any of the high end receivers rated as THX Ultra or Ultra 2 can handle 4 ohm speakers. I would also strongly suggest a receiver with a large toroidal power supply. At 130 watts, I am going to guess that your receiver is rated as THX Select and does not have a toroidal PS, which can technically handle nominal 4 ohm loads, but probably not with much aplomb.

Even a THX Utlra 2 rated receiver with a toroidal transformer will not drive the Thiels with the same ease as a dedicated 2 channel high current integrated or separate power amp of the same wattage rating. In order to fit all those electronics in the same chassis, corners have to be cut somewhere, not to mention noise introduced by having DACs in the box.
Here are test results on Ultra 2 receivers.Anything over two channels kills the power.7 time 4ohms will probably kill the receiver.Denon AVR4308 140 watts.Drops to 111 watts X7 at 8ohms@1khz.Not 20-20,000,might not be possible.Test link below.Yamaha RX-Z9 175 watts.test out at 138 watts X7 @1khz.Not 20-20,000 either.Typical SELECT2 acording to S&V.
I can't think of any receiver that will give a full bandwith
power with all channels driven at 4 ohms!

Denon test link>>>[]Yamaha RXZ9 test link>>>[]
I forgot to mention,A/V receivers use 8 ohms as the standard.They do not have to meet the old FTC standards that were made to regulate two channel stereo amps.
Thanks for the replies. Of the other brand speakers I mentioned, do any of them present an easier load than the Thiels for a receiver to drive?

The Receiver is a Yamaha RX-V1800. It is currently driving a set of Legacy Signature II left/right front speakers, plus a Paradigm center channel and PSB 5T surrounds. I am bi-amping the Legacys via the feature on the Yamaha that uses the surround back amps.

I set the Legacys and the PSBs to large in the receiver setup menu, and I often try the center on each of the available settings(small/large/none) to see which way I like it better.

The receiver seems to drive this setup OK in terms of not clipping at the levels I listen at, which is not super loud. But it sounds like that would not be the case with the Thiels.
What model Thiel are you thinking about?

If you are talking about anything model6 and higher you will need LOTS and LOTS of power and be able to handle 2 ohm loads and maybe lower.

A friend of mine has Thiel model 7s amd his new Moon W-7M 500 watt amps had to be modified by Simaudio to handle the load at loud volumes.

Thiels I think were not intended to be used with a receiver and I also agree with Mitch4t.
THX has nothing to do with weather you can handle Thiels, you will need real transformer power not chip power.
Most speakers built today do not have the constant loads Thiels have, we use Subs more now for that kind of bass.

Thiels are great speakers but are hard to power and give justice to with just any amp.
I was thinking of something like the 2.4 or 2.2

What about some of the other brands? Any experience?

My power amp is the Sherbourn 5/1500A, which is a 5 mono channel design. It has 5 toroidal transformers in it and is rated at 200wpc into 8 ohms, and I think 350wpc into 4 ohms. If this is not enough, I need to move on from the Thiel idea and look at other brands.
If your receiver has pre-outs you can run a two channel power amp to just the front and use the receiver power for all other channels.

When I first started about 8 years ago in college I was very tight on money and bought a pair of B&W 703s (90dB) and ran them off the receiver I already had (and Onkyo rated at 100 watts). At the time I thought it sounded good but I bought a cheap rotel amp (also rated at 100 watts) off of ebay and it made a world of difference.

The speakers had much more bass and improved in almost all areas. It was like I have bought different speakers. With that being said the Thiels impedance curve is much worse and will be a lot harder to drive the my old 703s.

If you want something small that you could tuck away out of sight you could look into class-d amps. They keep getting better... They are small, run cool and have lost of power for the money.
I've used Thiels for over 20 years now. I've tried quite a few different amps on different models. Unless your using something like the M series B&K amps, don't bother, and you can forget the rest. Sure these budget amps can hum a tune on the Thiels, but they'll never get them to sing to their capability. That's the one caveat with Thiels, they'll clearly demonstrate what proceeds them. If you can't afford to feed a Great Dane get something else. BTW, while the newer Thiels are more sensitive than the older ones, the older ones had an easier impedance load.