Tube DIY Asylum: Re: Input/driver for 2A3 parafeed by keto Do It Yourself (DIY) paradise for tube and SET project builders.

For Sale Ads FAQ / News / Events

Posted by keto (A ) on November 19, 2003 at 15:15:33

In Reply to: Input/driver for 2A3 parafeed posted by Tubefever on November 17, 2003 at 09:05:39:

I'm listening to a 6FQ7 input driver for a 2A3 amp, it is cap coupled to a 1:1+1 autoformer that then supplies the differential signals to the 2A3 pair. Because this set up is very similar to a cap/grid choke coupled SE circuit, I figure I could recommend it for your circuit. I use a Bottlehead C4S current source, set at 10mA, and a 220R cathode resistor, which yields a plate voltage of about 155V. The gain is such that with a 100K pot before the 6FQ7 the 2A3 will clip only on the last 2 or 3 volume settings. The 6FQ7 is of the "9AJ" pinout variety, and there are a lot of other dual triodes that can be rolled right in. 6N1P, 6H30, 6BZ7, etc... Below is a link which includes the specific circuit for a 6BZ7, closer to your SRPP. If you were to set up your amp for the 6BZ7, you could try many different tube types with little or no change to the circuit. Has proven to be a valuable option in my case, since I don't know how great (6FQ7) or so-so (6BZ7) will work in my system until I give them a try.

• http://www.mif.pg.gda.pl/homepages/frank/sheets/093/6/6BZ7.pdf   (Open in New Window)

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 ]

---