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 ]

---

4+4W all triode amplifier with 12AT7 and 6AS7

Posted by 6AS7_6SN7 on September 28, 2009 at 00:40:17

This is my 'summer time' amplifier (with much less waste heat than my previously published Stonehenge amplifier). It has been entirely built with surplus HW purchased at radio-ham fairs/e-bay auctions(overall expenditure for parts of about 100 Euro, tubes included).

Key Features:
- 'zero impedance' 300V HT power supply (that is, the amplifier is directly powered by rectification of 220 AC mains, with double isolation chassis and input isolation transformer)
- novel PP topology with automatic zero current imbalance (of the 70 mA bias current)
- output toroidal AC mains transformers for minimum flux leakage/stray capacitance and low cost
- output residual hum lower than 5 mV peak
- 6 dB overall NFB
- no PCB/all direct wiring

The distortion at rated power is almost entirely second harmonic (1%, see measured output spectrum).

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 © 2024, Audio Asylum, all rights reserved ]

---

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

---