Jump to content

Triode vs. Ultra Linear push-pull


space_cowboy

Recommended Posts

I really have no idea what this means, thus the question. Say a manufacturer will factory strap an integrated amp for either 25W triode, or 50W UL. Is there a way to describe the differences (pro or con) between the two modes without listening. The only tubes I have ever heard are my modest ASL stuff. So from a Klipsch viewpoint it would seem 25W would be plenty as I can attest 8W pushes KLF-20's just fine, and any speaker change would be to either La Scalas or Belles.

This is just out of curiosity, no purchase is really pending. Thanks for any comments, suggestions, or informative links.

Link to comment
Share on other sites

  • Replies 41
  • Created
  • Last Reply

Top Posters In This Topic

I'll try but others are better at explaining these things than am I.

In ultralinear mode a type of feedback signal is fed to the screen grid of the power tube. since it is say fourty % of the windings lower than the plate connection there is a phase difference between the grid and the plate. This either accelerates or retards the flow of electrons to the plate resulting in an increased plate current swing. This translates into more power across the output transformer.

In strapper or quasi-triode mode the screen grid is tied to the plate through a small value resistor. Since they are resistively coupled there is no phase shift between the elements and the screen grid can be considered invisible(nonexistant). Since there is no screen grid on a triode the reaction of the electrons is similiar to the triode; faster reaction clearer sound in most instances.

What differentiates Strapped triodes from true triodes is the third grid or beam focus element. This element is tied to and has the same potential as the cathode . This focuses the electrons toward the plate and repels and electrons that bounce off the plate back to the plate. letting the tube disipate more power than a true triode.

The net result is a faster clearer sound from a pentode tube, with a cost of some power.

Rick

Link to comment
Share on other sites

Odd, I always thought Ultra-linear sounded livelier than "triode". I don't know about the "clearer" thing, as I always thought "triode" sounded a little dark and warm. I think Ultra-linear sounds more neutral to me.

Ah, but give me a dirty pentode amp with lots of feedback. Now we're talkin Rock-n-Roll.

Link to comment
Share on other sites

The switch between triode and ultralinear for a pentode tube is easy and quickly reversible. The ultralinear tap from the output transformer is removed and insulated. The output tubes' screens are then tied to their grids with 200 ohm resistors. The output power is reduced roughly by 1/2. With 6550 output tubes in the Dyna Mk III's and Citation II's I have played with the sound has been much sweeter, and more of what one thinks of as "tube" like. I don't know with lower power amps. With the efficiency of Klipsches try it and I suspect that you will like it. Either way it's easy to switch.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...