tube amps and electrostatics

12-10-13: Bombaywalla: RE: Stereophile review of Green Mountain Speakers driven by OTL:

They may have given the speakers themselves a good review, but not when it's driven by an OTL amp. And it's those impedances/phase that cause it to act like a tone control.

Stereophile: Listening review of the Green Mountain Diamantes, half way down the page.
http://www.stereophile.com/floorloudspeakers/694green/index.html

And then the measurments by JA to back up what SS heard, first paragraph:
http://www.stereophile.com/content/green-mountain-audio-diamante-loudspeaker-measurements

Cheers George

Thanks for this info Georgelofi. The Diamantes were Green Mtn Audio's 1st offering back in 1994. Not a bad start - much better than most other speakers in the market at that time. There has been considerable advance since then & I believe that Roy Johnson has gotten the phase angles down much more so that the newer model speakers are more amplifier agnostic. I think now Roy Johnson is agreeable to the Atma-sphere M60 amplifier driving his speakers.

I need to point out to you Bombaywalla that this Green Mountain speaker is far from being a hard load, if fact it's quite easy.
As it's a 6ohm average with a not so bad phase angle of -30degrees.
The worst load frequency for an amp happens where they cross at 100hz where the impedance is 6.5ohms with -25degrees phase angle.
So this speaker can be regarded as quite an easy one for amps to drive.

Cheers George

Not to worry, enjoy the speakers; there are amplifiers up to the task, and with more to spare.

^^ Yup! We shown with Roy's speakers at audio shows in the past. Never had a problem with them.