KT150s in Audio Research Ref 110.

Did ARC say why the 150's aren't recommended?

They said the plate current is to high for the power supply I believe.

You’ll burn up the power transformer in time. You will shorten its life.
ARC power transformers are very expensive.

KT 120
Plate current 135 - 165 ma
Heater current 1.7 - 1.95 amp @6.3 Fil V
https://s3.amazonaws.com/tubedepot-com-production/spree/attached_files/ts-kt120.pdf?1382029860
~

KT150
Plate current 150 - 180 ma
Heater current 1.75 - 2.00 amp @6.3 Fil V
http://www.tubeampdoctor.com/images/File/data%20sheet%20KT150%20Tung-Sol.pdf

Exactly what I needed to see. Thank you jea48.  The Ref110 sounds awesome with the KT120 but I have 4 KT150 and was thinking about buying 4 more if the amp could handle the KT150s. 

samzx12 OP
KT150s in Audio Research Ref 110.

The Ref110 was originally made by AR for 6550’s
I had an amp that I tried 6550’s, KT90’s KT120’s and KT150 in, it suited all.
But I found it sounded the very best using the Green Label plain white box mil spec GE 6550’s, this tube sounds way out in front of all the others for sound quality, btw the glass envelope was twice the thickness, you could tell when you ficked it with your finger nail, there was just a dead thud, instead of a ping!
Just like these > https://www.ebay.co.uk/itm/202717315969

Cheers George