which tube mono blocks?

11-19-08: Detlof
Atma-Sphere Music Amplifier MA-2 Mk. III

Hasn't Ralph "Atmasphere" Karsten posted around here that all OTL amps prefer to work into higher impedance loads? The higher, the better, due to distortion issues.(did I get this right?)

I'm pretty sure he has recommended using Speltz Zero's impedance-matching external transformers to raise speakers below 4 ohms up to a more workable range.

Anyway, back to the original question. Jtwrace's Final 1000i's are actually rated in the 3 ohm range according to the website:

The simplicity of the new Inverter Technology™ design insures speaker impedance will remain well above 4 ohms across the entire frequency spectrum for the smaller speakers and above 3 Ohm for the larger models.

The 1000i are the largest panels they make and Dick Olsher's 2007 review states that they actually dip into the 2 ohm range.

Ronald Buining, one of Final's designers and engineers, explained that since the treble is emitted by a narrow strip, the speaker's capacitive loading is reduced. And it is primarily the reduced capacitance that is responsible for the impedance magnitude remaining at about 2 Ohm around 20kHz for the 1000i.

If that low of impedance and high power are a must, then think about Wolcott amplifiers. They are famous for driving the largest Soundlab A-1 panels without breaking a sweat.

Otherwise, get some Zero's and use the 3x or 4x multiplier taps, your tube amp choices will open exponentially.

11-20-08: Atmasphere
Darkmoebius, just for the record, I stated that about **all** amplifiers, tube *or* transistor!

Thanks for setting the record straight, I had a feeling I was getting something wrong.

11-23-08: Jtwrace
What do you guys think of the Van Alstine Ultra 550? Can it compete with any of the above mentioned products?

Not exactly an apples-to-apples comparison what with the VA Ultra 550's output being power MOSFETs instead of tubes.

11-25-08: Gallant_diva
Out of all the amps I have owned or listened, nothing compares to Tube Research Labs GT-400 or GT-800. These amps stand head and shoulder above anything else in terms of transparency, details, delicacy, balance, control, power, liquidity, or any other performance measure.

I wouldn't doubt that, but for $10,000 speakers, it seems a bit unrealistic to go with $140,000 amps even if it might be (remotely)possible to find them for $70k used.