Cathode Follower Ouput

Tube DIY Asylum

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

Guys,

Thought I would share this with the group...

I've been working on an inexpensive alternative to a DHT design using tetrodes and Pentodes on the output while trying to get the most linear and musical sound.

I have read about the Cathode Follower output approach at TubeCAD and other venues which basically seemed to discourage this approach because of the high voltage swing demand on the driver.I believe Dick Olsher has marketed a Cathode Follower which is the only offering of this type that I have read about. Seems like some OTL builders have taken this approach.

Over the last couple of days, I've been reworking the driver section of my experimental SE 6L6/KT66 amp. The driver section now consists of (2) halves of a 6SN7 with the first halve loaded with a CCS and RC coupled to the second halve which is conventionally loaded. This driver section yielded way too much gain for a regular Plate loaded output section.

I then configured the output in a cathode follower and gave it a try...

I was pleasantly surprised with the results. My biggest complaint with the Terodes and Pentodes (even triode strapped) is the lack of output dampening due to higher than desired output impedance. I haven't ran any calcs to figure up the output impedance but the result was a very musical presentation with very tight but rich lower end and plenty of gain.

This amp is configured similar to the Ciuffoli SETA amp only I'm loading the first stage with a CCS while Ciuffoli loaded the second stage by IT coupling to the output section. My approach is RC coupled...(I'm trying to do this on the cheap.) He also uses a KT88/90 while I'm using it's little cousin.

For those who haven't tried this, I encourage you to give it a try.

Keep Building ;> )

Stuben

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

Atma-Sphere Music Systems, Inc.

Topic - Cathode Follower Ouput - Stuben 11:10:10 07/23/11 (4)

RE: Cathode Follower Ouput - danlaudionut 12:17:39 07/23/11 (3)

RE: Cathode Follower Ouput - Stuben 15:21:19 07/26/11 (0)

RE: Cathode Follower Ouput - Stuben 13:04:57 07/23/11 (1)

RE: Cathode Follower Ouput - danlaudionut 13:13:03 07/23/11 (0)

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