Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders.

---

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

---

[ Alert Moderator ]

---

RE: Transformer impedance for an 8417 tube?

Posted by drlowmu (M) on August 26, 2012 at 07:29:40

In Reply to: Transformer impedance for an 8417 tube? posted by BofService on August 26, 2012 at 06:11:51:

Yes, that sounds about right for TWO tubes, push pull. As I recall, many Bogens ( M-100s?) used four output tubes in push pull parallel, some even eight, per channel (M-200s?). The use of four tubes would mean the primary's Z is HALF of 4.2 K, or 2.1 K Ohm. As I recall, the 200 Watt eight output tubes per channel Bogens used TWO output trannies in parallel, to get it to work. It was VERY wide band in its published frequency response, so it may be a stellar 2.1 K or so trannie.

An amp I used to mod a lot, the Paoli 60M, built on a Dynaco MK 3 chassis and using their iron, used either 6550's, KT-88s, or 8417s, in push pull. Look up the Z of a MK 3 output trannie.

If you triode connect any of the output types I mentioned, matching Z to the tube is greatly relaxed, triodes are very tolerant of mis matches, not so with pentodes.

You can measure the primary's Z by applying and measuring AC voltages between the primary and the 8 Ohm Taps, and using simple computations to mathematically arrive at the "unknown" primary's Z, using square roots, after the turns-ratio is determined. Google search that, or, search this Forum, many times it has been covered.

Jeff Medwin

Edits: 08/26/12 08/26/12 08/26/12

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

Western Glow Tube Service

---

[ 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 ]

---