My 12AX7 zero negative feedback preamp, with measurement

alexw88 · 22nd January 2008, 02:15 PM

All of my previous projects are Opamp based pre and power amps. Now I have tried tubes and I really love it! I am a tube newbie so I hope I can learn more.....

My 12AX7 zero negative feedback pre-amp : http://www.shine7.com/audio/12ax7_pre.htm

Here are some photos and measurements from the above page :

SY · 22nd January 2008, 02:21 PM

Very nice construction, and the distortion spectrum looks excellent. What is the output level where it was taken?

I like those prototype boards and terminals. Where did you get them?

alexw88 · 22nd January 2008, 02:24 PM

Thanks, the output is at 1V p-p.

I have got the prototype board and the terminals at a local DIY components shop in Hong Kong.

dhaen · 22nd January 2008, 02:36 PM

I agree: nice construction. Also good philosophy IMO

GlidingDutchman · 22nd January 2008, 03:32 PM

Bravo! Very nice indeed!

I envy your skill!

GD

CaliforniaBob · 22nd January 2008, 04:17 PM

love your site!

Bob

zigzagflux · 22nd January 2008, 04:18 PM

That's freaking gorgeous !

daanve · 22nd January 2008, 06:50 PM

SY,

if you ever make it to HongKong you have to visit the store where I saw those solder stands.
Bush Electronic Supply, in an alley behind a pretty big street in Hong Kong central or the Centre.
You enter the alley, then walk up some steps and you enter the shop. Amazing, the contrast.

http://hktubeaudio.homestead.com/files/Central_tube.htm

Daan

Majestic · 22nd January 2008, 07:11 PM

Very nice looking job, Alex!

(I need to get myself some of those prototype boards too!)

SY · 22nd January 2008, 07:37 PM

Daan, I still have to get back to Holland before I can start thinking about travel for pleasure!

22nd January 2008, 02:15 PM	#1
alexw88 diyAudio Member Join Date: Mar 2004 Location: HK	My 12ax7 zero negative feedback preamp, with measurement All of my previous projects are Opamp based pre and power amps. Now I have tried tubes and I really love it! I am a tube newbie so I hope I can learn more..... My 12AX7 zero negative feedback pre-amp : http://www.shine7.com/audio/12ax7_pre.htm Here are some photos and measurements from the above page : __________________ My Audio Page

22nd January 2008, 02:21 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Very nice construction, and the distortion spectrum looks excellent. What is the output level where it was taken? I like those prototype boards and terminals. Where did you get them? __________________ "...we stumble and get up, we are sad, confident, insecure, feel loneliness and joy and love. There is nothing more; but I want nothing more.” - Christopher Hitchens 1949-2011

22nd January 2008, 02:24 PM	#3
alexw88 diyAudio Member Join Date: Mar 2004 Location: HK	Thanks, the output is at 1V p-p. I have got the prototype board and the terminals at a local DIY components shop in Hong Kong. __________________ My Audio Page

22nd January 2008, 07:11 PM	#9
Majestic diyAudio Member Join Date: Mar 2004 Location: Melbourne	Very nice looking job, Alex! (I need to get myself some of those prototype boards too!) __________________ check out my avitar and go easy on me ok? :-)

22nd January 2008, 07:37 PM	#10
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Daan, I still have to get back to Holland before I can start thinking about travel for pleasure! __________________ "...we stumble and get up, we are sad, confident, insecure, feel loneliness and joy and love. There is nothing more; but I want nothing more.” - Christopher Hitchens 1949-2011

22nd January 2008, 02:36 PM	#4
dhaen diyAudio Moderator Emeritus Join Date: Jun 2002 Location: U.K.	I agree: nice construction. Also good philosophy IMO

22nd January 2008, 03:32 PM	#5
GlidingDutchman diyAudio Member Join Date: Nov 2007	Bravo! Very nice indeed! I envy your skill! GD

22nd January 2008, 04:17 PM	#6
CaliforniaBob diyAudio Member Join Date: May 2003 Location: SF	love your site! Bob

22nd January 2008, 04:18 PM	#7
zigzagflux diyAudio Member Join Date: Oct 2006	That's freaking gorgeous !

22nd January 2008, 06:50 PM	#8
daanve diyAudio Member Join Date: Feb 2004 Location: Amsterdam, NL	SY, if you ever make it to HongKong you have to visit the store where I saw those solder stands. Bush Electronic Supply, in an alley behind a pretty big street in Hong Kong central or the Centre. You enter the alley, then walk up some steps and you enter the shop. Amazing, the contrast. http://hktubeaudio.homestead.com/files/Central_tube.htm Daan

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