Vinyl Asylum Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ.

---

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

---

[ Alert Moderator ]

---

3 phase

Posted by Mark Kelly (M) on February 8, 2017 at 19:39:15

In Reply to: RE: For Coffee Phil re Garrard motors posted by coffee-phil on February 8, 2017 at 10:32:31:

The main requirement for that motor is three decent amps that put out 20 watts or so.

I used to use the old T amps but couldn't find anything SS I liked once they were withdrawn. I went to using V/Ts, intially KT88s and then 300Bs. I designed but never got around to building a three phase supply using three sets of 6L6s. I still have all the iron and the valves lying around here somewhere.

Getting the three phases is pretty simple if you have a reliable quadrature supply, it so happens that common resistor values are often separated by ratios that are very close to square roots. Particularly 13 / 7.5 is very close to Sqrt 3, you can use this to derive three phases from two by vector summation, observing that Y + Sqrt3*X = 2*60 degrees (WRT Y) = 2*120 degrees (WRT -Y).

I haven't seen the threads Tom references below, maybe they'll have a good recommendation for an amp.


Mark Kelly

Edits: 02/08/17

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

Analog Engineering Associates

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

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

---