Planar Speaker Asylum Welcome! Need support, you got it. Or share your ideas and experiences.

---

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Planar Speaker Asylum ]

---

[ Alert Moderator ]

---

RE: Tri-amping T IV-A's with tubes?

Posted by UncleMeat (A) on December 31, 2024 at 21:51:14

In Reply to: Tri-amping T IV-A's with tubes? posted by AkuAnkka on November 17, 2024 at 08:45:52:

Just to give some point of reference to your question regarding running T-IVA's with tube amps. I have rebuilt a set of T-IV (non-'a') about a year ago. I'm running them with the original XO boxes, and have modified the internal crossovers for a flatter response and to 'fix' the weak midrange that was the main criticism of them and why Magnepan updated them to the 'a' revision. I have not re-capped the crossovers and am running them full-range, not bi-amped or active XO.

These speakers sound fantastic without seeming to be 'power hungry'. I've run them with Class A/B (push-pull) tube amps that are only capable of about 60WPC max, and likely lower power with the lower power tubes I am running (Svetlana 6550's vs. spec'd KT-120's).

My system is not in a huge room, so I don't need a large amount of power to drive them to levels that are 'uncomfortable' in volume. I have run the various tube amps up to levels where they begin to clip, but tube amps clip 'softly' and they have not caused any problems with the ribbons. By the time the amp is running at that volume level, my neighbors would be getting upset and my ears wouldn't be able to take the in-room volume for very long either.

When I first started on the rebuild of these, I had blown out one the tweeters (which were old/loose in their frames to begin with) because of a tube pre-amp microphonic feedback loop that overpowered one of them. The tweeters were not separately fused from the mids (Magnepan's original design). If your tweeters are not separately fused, make sure you order the update kit from Magnepan for them.

I don't think you'll have trouble driving the ribbons/mids with tube amps that are 20-30W/amp section. If you can drive the entire set with amps that are 100WPC or less at comfortable listening levels, you should be fine. Keep in mind that getting rid of passive components should also increase the 'efficiency' of each driver as well.

This post is made possible by the generous support of people like you and our sponsors:

Parts Connexion

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---