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New KT150 tubes?

Has anyone any experience with these pretty new tubes. There are already one or 2 amps I know of, that use them. The review of one of these amps in a UK magazine suggested they were a little warmer and more natural sounding than the nearly new KT120's

The article also suggested they were a straight swap for KT120 based amps, with no adjustment necessary. They are more than twice the cost of KT120's, but still not too costly compared with NOS tubes. I know changing from KT88's or 90's to 120's. did require some amp modification. I have an ARC reference 75 and might want to try the new tubes at some point, ARC don't seem to have a customer E-mail service, to ask the question
david12

Showing 2 responses by milimetr

milimetr
141 posts
 
I explored if the new KT150 tubes can be used in any of the Jadis amplifiers (besides of i50 designed for KT150).

I got reply that KT150 are not interchangable with KT120, at least in Jadis amplifiers.
milimetr
141 posts
 
Ok. I have similar concern.
Have an aplifier designed to work with 6550/KT88 family of tubes.
Now I have KT120 installed - ok by manufacturer.

I was considering using KT150 im my amplifier, but manufacturer adviced not to do so. The point is not that both KT120 and KT150 have almost the same current draw. The point is different characteristics (curves) in KT150.
When used in amplifier with plate voltage lets say - 485 V and fixed bias point using KT150 will lead to use the tube in non optimal characteristic point (not the most linear part of characteristic). This is at least explanation I got from amplifier manufacturer.

Using KT150 in their optimum requires output transformer to be specially wound for them as well as setting proper working plate voltages.
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