Home Computer Audio Asylum

Music servers and other computer based digital audio technologies.

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Computer Audio Asylum ]
[ Alert Moderator ]

Why the 71A

Gang,

As many of you know I have been making tube amps and preamps since 1981. My first SET amp was the Sole 845 as I did not think anyone would pay for an 8W 300B amplifier. But then Mike Marx (SND Tube Sales) sold me a bunch of 45's tubes and I realized that I could run my ProAc Response 2's on a couple of watts pretty easily. Some of you may remember when Corey Greenburg got hasseled for using one of CCOS 45 amps in the review of the ProAc speakers when he wrote for Stereophile. The Cardinal came out in like 1988 and the design was ripped off from day one. So the version 2 and 3 quickly came out after that.

I had made many solid state amplifiers, heck even sold about 200 of them. Also sold about 400 push pull EL34 and KT88 amps before I realized how much a triode can make a difference.

So for the Crimson I looked at all the Directly Heated Triodes. The 71A is an amplifier output triode. But really who can live with sub 1W output (well other than me)?

The 71A is a perfect tube for the output. So then we created an output transformer for the job and then the circuit was built from that.

The other similar tubes the Western Electric 101L/M and the Telefunken RE134 are also very interesting tubes but of course a lot harder to find.

They are all very good candidates for any audio product. But also a lot harder to implement correctly. Because these require a lot of custom magnetics that companies don't want to spend the cash for anymore.

Thanks and have fun!
Gordon
J. Gordon Rankin

This post is made possible by the generous support of people like you and our sponsors:
  Atma-Sphere Music Systems, Inc.  

Follow Ups Full Thread
Follow Ups
FAQ

Post a Message!

 Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.

[ Top 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 ]