2. amps-preamps
  3. 192205-171531

I hate to say it, but now I think maybe I like my amp in ultralinear mode versus triode

It's a Cary V-12; it features a dozen EL34s and each pair has a switch in between them that configures that pair to either triode or ultralinear. In full triode Cary listed in the specs that it makes 50 wpc and in full ultralinear 100 wpc.   For most of the twenty three years that I have owned this amp I have always felt that I preferred triode except for the occasions that I wanted to full out blast (it has literally been many years since I've felt the need to full out blast).

However, today I experimented with a couple of things in my system, and after listening to the same "Jazz Essentials" (compilation) red book CD a couple of times all the way through, the next thing I experimented with was switching to full ultralinear.

Maybe there was more "PRaT"?  (Which is a term I am still not sure that I completely grasp.)  Maybe . . . but what I do feel I noted for sure was that the imaging (particularly the imaging in the center) had more weight (meatier?) and was presented more forward, which I actually like.

I put a few more hours in (one more time with Jazz Essentials, Holly Cole/It Happened One Night, Dave's True Story/Sex Without Bodies, selected tracks from Rebecca Pigeon/The Raven and Once Blue/self titled and Norah Jones/Feels Like Home) after switching to ultralinear.  (No booze during this session, just coffee.) The jury is still out on this, but I do have some CDs in mind that I want to listen to over the next few days as I continue to evaluate.  

immatthewj
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atmasphere's avatar
atmasphere
11,841 posts
 

I wonder if the output transformer of amplifier with the triode/UL option is optimized equally for both modes, or if the default is to design for best operation in UL, then simply switch the screens to pair with the plates of the output tubes (usually via a resistor)?

@pickindoug To do it properly, the output transformer would have to have taps for triode operation since the optimal plate to plate load for a power pentode wired in triode is a lower impedance than that used for UL operation. That could make the transformer a lot more expensive and the switching a bit more complex.

pickindoug
59 posts
 

@atmasphere  Yes, that's the issue with engineering options like triode vs UL.  Based on all the OPT I've used, designed around, etc, a UL OPT will require a certain NFB characteristic for best performance.  Using the same level of NFB when the UL taps are lifted may not be the optimal level for the reasons NFB is used.  Marketing loves to have perceived needs to sell to.

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