Mono blocks-High current/low impedance...options?

H2O

output impedance: 0.005 ohms

input impedance: 8 Kohms

minimum load impedance: 2 ohms

current output: 45 amps.

Hi Ralph,

Actually I had success with tube and solid state preamps with the M-100's. I would avoid tube preamps with high output impedence like CJ's though (700 ohms). Tube pre's with output impedence at or below 300 ohms, like BAT worked as well or better with the M-100's than the solid state preamps from Threshold/Krell/Mark Levinson that I tried with them.

John

Hey Vince.......

You forgot to tell us what the frequency response looks like @ 2 ohms. The current output you give is the peak value, which means only for a very short transient. All it really says is that with an 80V rail, and a 2 ohm load, it should be able to operate for a short period of time without melting.

(Of course, that assumes that the supply voltage doesn't drop under such conditions.......etc.)

But if you want an amp that puts out 1 kW into only 4 ohms, then have I got a deal for you.............

I know....behave and stop making trouble. [joke]

Hey Art - send your most robust amp hither and we'll smoke it. ;)

By the way, my speakers are .8 ohm. I don't listen to music higher that 90 dB as a rule. With Henry's Fire preamp, I'm getting +20 amp transients. There is a nearby audiophile that is using the stereo version of the H2O Signature on 4 ohm speakers. The percussion was terrifying.

Watch for the next H2O reviews at Positive Feedback.

I know....you're itching to get your hands on some of our stuff. Maybe when more of our loaners come back, we'll work something out.

Irony is........you would think that an amp that can do 1 kW into 4 ohms, and can work into loads as low as 2 ohms, would be great on a really difficult, power hungry load. That is what we thought.

Problem with all ICEpower modules is the frequency response tends to peak as the load impedance goes lower. While the peak is above the audio range, it still tends to tilt the HF response.

With an 8 load, I can easily understand why you are so happy with Henry's amps. The 250 doesn't peak too much, and while the 500 does a bit more, it is manageable. At 8 ohms, that is.

You only run into severe peaking problems with loads below 4 ohms. For those loads, the peaking is shifted into the audio band. This has the additional detrimental effect of causing the very top (18-20 kHz) to drop off rather quickly. Again, not too bad in the 250, so-so in the 500, but way too much with the 1000ASP. So, you end up with a peak around 16 kHz, and a sharp drop at 20 kHz with the big module. (If you look closely at their specs, they only spec the stand-alone 1000W module for 6 kHz or so.)

OK........crux of all this:

I know that there are companies selling amps using the 1000ASP modules. Some of them may even be friends of mine.

BUT:

I do not recommend them to be used with very low impedance loads. Seems like a waste, as why would anyone with anything other than an inefficent, low impedance load need an amp that puts out 1 kW?

Pssst........if you need a kilowatt for a (sub) woofer application, call me. Prototype units available at a great price.