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 ]

---

My 4P1L SE build

Posted by andy evans (A) on September 24, 2015 at 08:20:33

My usual amp is a PSE 4P1L amp. 4P1L into LL1660/18mA into parallel 4P1L with LL1620/80mA OPT. All filament bias. I'm pretty happy with it and it's lasted 3 years in my system.

On a whim I threw together some parts I had left over from other projects and produced a SE 4P1L with 4P1L input, choke loaded with a teflon FT-3 coupling cap and a LL1682/50mA OPT. I didn't expect much out of this, and for a start thought it would never drive my Alpair 10s. I thought the primary impedance of the LL1682 at 5K into 5R was too high. I thought the Valab 50H plate choke was going to be pretty average. I wasn't expecting the sound that came out of the speakers.

Well, this is as good an amp as anything I've ever built - all the usual suspects like 300b and 2a3 SETs and so on. I'm just amazed. Very detailed indeed and effortlessly smooth, with very good timbre to acoustic instruments, voice and piano. This is a much cheaper version of a 45 amp, with cheap and easily sourced tubes. I would not be surprised if it sounded just as good as most 45 designs.

Here's the schematic. The parts are relatively cheap for an amp like this, though the PSU and filament supplies are quite complex.

Edits: 09/24/15

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

Sonic Craft

---

[ 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 ]

---