audio research REF 150

Good evening .

I have been having a little "FuN" switching the output taps on a REF-150 driving Martin Logan CLX's and find myself concurring with a post made by another member , sfischer1, earlier in this thread ~

"11-21-11: Sfischer1
Just spent a couple full days using a demo 150 with my Martin Logan CLX full range electrostatics. Even though the MLs have a tough impedance that drops to an ohm at high frequencies, the best sounding tap by a large margin was the 16 ohm connection"

Considering the CLX's nominal 6 Ohms impedance dipping down to 0.7 Ohms @ 20K would not our subjective findings contradict the recommendation made by John Atkinson contained within the Stereophile review ~

" All taps behaved similarly when it came to the maximum output power. Into a load twice the nominal tap value, the Ref150 clipped (defined as 1% THD) at 90W (19.6dBW, fig.4). Into the nominal tap value, it clipped at the specified 150W (21.75dBW, fig.5), but with a higher level of distortion. Into half the tap value, the amplifier clipped at 80W (13dBW, fig.6), but with even higher distortion at lower powers. It is important, therefore, to use the transformer tap that best matches your preferred loudspeaker."

" with the caveat that it performs at its best with loudspeakers that have impedances equal to or higher than the nominal output-tap impedance.—John Atkinson "

Where is that 'confused' emoticon when one needs one !

has anybody tried the tung-sol kt 120 or 6550 in this power amp I have 1500 hrs may need to change soon

Ollies ... I assume by your reference to "this power amp" that are referring to the Ref 150. If so, I am puzzled by your question because KT-120s come standard with the Ref 150.

Although there may be other companies that manufacture the KT-120 ... the ARC standard issue *IS* Tung Sol, a redo by the Reflektor company in Russia. The 6550 does NOT come standard with the Ref 150.

Perhaps I do not understand your post. If not, please explain.

I bought ref150 2 weeks ago and at 38 tube hours could not be happier. And many people are saying it will get better at 600 hours ! Boy oh boy

The Ref 5 SE preamp and Ref 150 amp were bought at same time replacing McIntosh C48 and MC302. System has now much better definition across all frequencies. I think "High Definition" moniker on the faceplate was actually delivered with flying colors. Very wide soundstage, a lot of 3D, very detailed highs, enjoyable decay on guitar strings and cymbals. Can hear bass drum at the background of group of musicians. Amazing.

MCD500/Mac Mini > Meitner MA-1 > Ref 5 SE > Ref 150 > Sonus Faber Amati Futura. All cabling, power distribution uses Nordost/Valhalla version 1.

01-03-15: Adg243
I bought ref150 2 weeks ago and at 38 tube hours could not be happier. And many people are saying it will get better at 600 hours ! Boy oh boy

Congratulations! I have 330 hours on my Ref250 and it sounds excellent.

What color is the capacitors in your Ref150? In mine, 4 of the 6 small ones are gold and big ones are all white.

Does anyone have a audioresearch service manual?